THE 13.3503me AND YWSLOCATBON
OF RADIOSTRONTEUM BY THE
LEAVES, FRUiTS AND ROOTS OF CERTAlN
VEGETABLE PLANTS

Thai: for H10 Dam of Ph. D.
MiCHiGAN STATE COLLEGE
Dudley Cari Martin
1954

 

 

THESIS

This is to certify that the

thesis entitled

THE ABSORPTION AND TRANSLOCATIOI‘J OF RADIOSTRONTIUM
BY THE LEAVES, FRUITS AND ROOTS OF
CERTAIN VEGETABLE PLANTS

presented by

D1dley Carl Martin

has been accepted towards fulfillment
of the requirements for

Ph . D. degree in WW8

Jimé/wm

Major professor

Date $AA£7 30/. /7~5-,5(

0-169

 

 

THE ABSORPTION AND TRANSLOCATION OF RADIOSTRONTIUM
BY THE LEAVES, FRUITS AND ROOTS OF
CERTAIN VEGETABLE PLANTS

13?
Dudley Carl Martin

*

A THESIS

Submitted to the School of Graduate Studies of Michigan
State College of Agriculture and Applied Science
in partial fulfillment of the requirements
for the degree of

DOCTOR OF PHILOSOPHY

Department of Horticulture

19Sh

THES‘S

 

,l47-;u

ACKNOWLEDGEMENTS

The author is deeply indebted to Dr. S. H.'Wittwer,
Professor of_Horticulture, Michigan State College for his
sincere interest, competent guidance, and personal friend-
liness in connection with the preparation of this thesis.
Appreciation is also given to other members of the guidance
committee: Professor 0. D. Ball, Department of Chemistry;
Dr. R. L. Carolus, Department of Horticulture; Dr. G. P.
Steinbauer, Department of Botany and Plant Pathology; and

_Dr. L. M. Turk, Director of the ExPeriment Station.

All members of the Department of Horticulture are thanked
for their friendliness and encouragement, particularly Dr. H.
B. Tukey and Dr. A. L. Kenworthy.

Thanks are also given to Mr. O. N. flinsvark tor his as-
sistance in all phases of the chemical analyses and to Mr. R.
A. Bacon for performing the spectrographic analyses.

The author is indebted to the Biological.and.Medical
Division of the United States Atomic Energy Commission for
supplying the radioactive isotopes and.providing the finan-
cial support (Contract AT-(ll-ll-159) which.made this study

possible.

ii

34-04-81.

THE ABSORPTION AND TRANSLOCATION OF RADIOSTRONTIUM
BY THE LEAVES, FRUITS AND ROOTS OF
CERTAIN VEGETABLE PLANTS

By
Dudley Carl Martin

AN ABSTRACT

Submitted to the School of Graduate Studies of Michigan
State College of Agriculture and Applied Science
in partial fulfillment of the requirements
for the degree of

DOCTOR OF PHILOSOPHY

Department of Horticulture

Year 19Sh

Approved by

Dudley Carl Martin
1

The relatively large amount of strontium present in
the products of uranium fission has stimulated new interest
in the qualitative and quantitative aspects of strontium
absorption and translocation by plants. From the standpoint
of radioactive contamination of crop plants, the.absorption
by leaves and fruits becomes at least equal in importance
to root absorption. In this investigation tomato, beet and
bean plants were used in sand culture to study both root and
foliage absorption of radiostrontium, radiocalcium.and
radiobarium. Both the spectrograph and the flame spectro-
photometer were used to quantitatively analyze plant tissues
for strontium, calcium, potassium, magnesium, phosphorus,
boron, iron, manganese and copper. Autoradiography and
radioactive sample counting were the important isotope tech—
niques employed.

Strontium applied to the roots of tomato, beet and bean
plants was absorbed by the roots and translocated to all
above ground plant parts. Generally its absorption was pro-
portional to its concentration in the nutrient solution,
and also to its concentration relative to calcium, providing
the treatment period was long enough for equilibrium.tol
occur. Strontium can accumulate in tomato and best tissues
in amounts almost equivalent to the normal calcium content,

but at such high concentrations it is toxic to both plants.

Dudley Carl Martin
Z

Beets can accumulate higher strontium concentrations in

the plant tops and are less sensitive to strontium toxicity.
Strontium and calcium in the same nutrient solution mutually
favor the absorption of each other as compared to the same
amount of strontium or calcium alone. The effect of high
strontium and low calcium content of plant tissues upon

the absorption of other nutrients is discussed.

Autoradiographic studies indicated that radiocalcium,
radiostrontiwm and radiobarium are absorbed by tomato and
beet roots and translocated to all above ground plant
parts. The upward translocation of strontium is greater
than that of barium.but both elements tend to accumulate
in the vascular tissues. Tomato fruits accumulate rela-
tively little strontium, probably because of the low calcium
requirement.

Tomato plants high in calcium.alwsys absorbed more
strontium from.a root application than those low in cal-
cium when the applied strontium.was in ionic form. how-
ever when the applied strontium was chelated, absorption
was greater in tomato plants low in calcium. Plant cal-
cium content had little effect on strontium absorption by
beets. A

In contrast to the free movement upwards and high ac-
cumulation of strontium from a root application, the move-

ment of strontium from the site of a foliage or fruit

Dudley Carl Martin
3

application was very slight or completely lacking. Bean
and beet plants showed a somewhat greater downward move-
ment than tomato plants but in neither was the amount
translocated more than a trace of that applied. This was
likewise true of calcium and barium. Chelation of stron-
tium did not increase translocation away from treated
tomato leaves or fruits. By means of autoradiography it
was demonstrated that radiostrontium.can penetrate the
intact skin of a tomato fruit and accumulate in the inner

tissues.

.t.

4?. ”BE

2??
. i

!

 

l..._._

ACKIIO'.~."I
I . III:
II. 331
III. THE
IV. MATi

V. REST

HrT‘v-A

VI. DISCng
V11- 5mm

VIII. 1.121152%”

 

TABLE OF CONTENTS
Page
ACKNOWEDGMNTS O O O O 0 O O O O O O O O O O O 0 ii
I. INTRODUCTION . . . . . . . . . . . . . . . . . 1
II. REVIEW OF LITERATURE O I I O O O O O O O O O O O 2
‘III. ’THE PROBLEM FOR INVESTIGATION . . . . . . . . . . 13
IV. MATERIALS AND METHODS . . . . . . . . . . . . . IN
V. RESULTS 0 0 0 o 0 0 0 o 0 0 o 0 e o o o 0 31
A. Absorption and translocation of strontium in
tomato and beet plants as determined by
chemical analysis . . . . . . . . . . . . . 31
Experiment 1 o o o 0 o o 0 0 0 0 0 0 0 0 0 3].
Experiment 2 0 0 0 0 e 0 0 o 0 o 0 0 0 0 o 37
Experiment 3 0 o o o 0 o o o 0 0 o 0 e 0 0 71
B. Comparative absorption and translocation of
strontium, calcium and barium in tomato, beet

and bean plants as determined by auto.
radiography................ 7“.

. . . . . . . . gh

O O O O O I O O 86

Experiment h . . . . . .
Experiment 5 . . . . . .
Experiment 6 . . . . . .

C. Comparative absorption and translocation of
strontium, calcium and barium in tomato and
beet plants as indicated by radioactive
isotopes 00.00000000000000 90

Experiment 7 0 o 0 0 0 o o o 0 0 0 0 0 0 0 90

Experiment 8 . . . . O . . . . O . . . . . 91+

EJCP erment 9 0 0 0 0 0 0 0 e 0 0 0 0 o o 0 99

VI. DISCUSSION 0 . . . 0 . . 0 . o 0 . . . . . . 11h
VII 0 SW 0 O 0 o 0 O 0 o o o o o 0 o 0 0 o 125

VIII 0 LITERATURE CITED 0 O O o O o O O O 0 O o o 0 0 0 128

111

TABLE
I.

II.

III.

IV.

v.

VI.

VII.

VIII.

IX.

LIST OF TABLES

Conditions used for the flame photometric
determination of several elements present in
plant 88h 0 0 0 0 0 0 o o 0 0 o o o o 0 o 0 0

Increases in the percent transmittance of
various concentrations of strontium caused by

the flame interference by various levels of
p0t3881um.and C81C1um' 0 0 o 0,. o 0 0 0 0 e o o

The absorption and translocation of calcium.and
strontium by the roots and leaves of the tomato
and beet at high and low levels of calcium.
(Values given are in milligrams per gram‘of dry
tissue - mean of four replications) . . . . . . .

Total strontium accumulated by the roots and
leaves of the tomato and best at high and low
levels of calcium (Milligrams for total plant
organ - mean of four replications) . . . . . . .

nutrient solution formulations supplied to
tomato and beet plants grown for prolonged
pBPIOdS 0 0 o 0 0 o 0 o o o 0 0 o o 0 0 0 0

The influence of calciwm-strontium.nutrient
solutions on heights of tomato and beet plants
and diameters of beet roots grown for various
lengths of time (Mean of five plants) . . . . . .

The influence of calciumpstrontium nutrient
solutions on the dry weight of tomato plants
grown for 30 and no days (Grams per plant) . . .

The influence of calcium-strontium nutrient
solutions on the dry weight of beet plants grown
for as, 68, and 90 days. (Grams per plant) . . .

Dry weight top/root ratios of tomato and beet
plants grown for various lengths of time in
nutrient solutions containing different amounts
of calcium and strontium. (Values given are the
mean or five plants) 0 o 0 0 0 0 e 0 0 o o 0 0 0

iv

Page

20

23

35

36

38

h?

as

A9

53

LIST OF TABLES (Cont.)

Page
X. Percent dry weight of tomato and beet plants
grown in various calciumpstrontium nutrient
solutions and harvested at different time
intervals. (Values given are the mean of five
plantS.) e e e e e e e e e e e e e e e e e e 54

XI. The influence of various calcium-strontium
nutrient solutions on the mineral content of
tomato plants treated for as days. (Spectro-
graphic analysis. Concentration expressed as
percent or the dry weight.) 0 e e e e e e e e e 0 Sb

XII. The influence of various calciumpstrontium
nutrient solutions on the mineral content of
best plants treated for 90 days. (Spectro-
graphic analysis. Concentration expressed as
percent of the dry weight.) . . . . . . . . . . . 57

XIII. The influence of various calciumpstrontium
nutrient solutions on the potassium, calcium.and
strontium content of tomato plants treated for
30 and 146 days. (Flame photometric analysis.
Concentration expressed as percent of the dry
weight.) 0 O O O O O O O O O O O O O O O O O 58

XIV. The influence of various calcium-strontium
nutrient solutions on the potassium,calcimm
and strontium.content of beet plants treated
for as, 65, and 90 days.) (Flame photometric
analysis. Concentration expressed as percent of
the dry weight.) 0 e e e 0 e e e e e e e e e e e 59

XV. Calcium and strontium content of tomato plants
expressed as milliequivalents per gram of dry
tissue after 30 and us days of growth in various
calciumpstrontium.nutrient solutions. (Values
given are the average of five plants.) . . . . . 67

XVI. Calcium and strontium content of best plants
expressed as milliequivalents per gram of dry
tissue after as, 66 and 90 days of growth in
various calcium-strontium nutrient solutions.
(Values given are the average of five plants.). . 68

XVII. Calcium and strontium content of tomato, beet,

eggplant and pepper plants grown under field
conditions 0 e e e o e e e e e e e e e e e e e 73

'Y

 

 

 

—-—- — ._'v-m
. . . .. f _ ‘_. —

ll

XVIII.

XIX.

XXI.

XXII.

XXIII.

XXIV.

LIST OF TABLES (Cont.)

Page

Characteristics of radioisotope solutions
utilized for treating plants for autoradiography,
and exposure times for the autoradiograms . . . .

Absorption and redistribution of calcium,

strontium and barium by leaves and roots of

beet plants as indicated by radioactive isotopes.
(Average of four replications). . . . . . . . . . 93

The absorption and translocation of strontium by
the fggit, leaves and roots of tomato as indicated
by Sr (Average of three replications.) . . . . 9B

Micrograms of strontium absorbed by the roots and
translocated to the tops of treatment #1 tomato
plants during eight days of treatment with.
strontium.chloride. (Average of four repli-
cations.) coo-00.000.00.0000106

Micrograms of strontium absorbed by the roots and
translocated to the tops of tomato plants as
influenced by tissue calcium content and the

chemical form of applied strontium. (Treatment
period 6 days. Average of four replications.) . l0?

Summary of strontium translocation in tomato

plants from root, fruit and leaf applications

to plants high in total calcium. (Mean of four
replications.).................lll

Summary of strontium translocation in tomato

plants from root, fruit and leaf applications

to plants low in total calcium. (Mean of four
replications.) eoeeeeeeeeeeeeeeelld

vi

FIGURE

1.

2.

3.

u.

b.

6.

7.

9.

10.

LIST OF FlGURhS

Standard curves for flame photometry. The re-
lationship between flame intensity and concen-
tration of (A) potassium, (B) sOdium, (C) stron-
tium, (D) calcium . . . . . . . . . . . . . . . .

Corrections applied to the observed strontium
transmittance to account for flame interference
by (A) potassium and (B) calcium . . . . . . . .

Beet plants grown for 66 days in nutrient solu-
tions with decreasing calcium content and no
Strontium eeeeeeeoeoeeeeeeee

Beet plants grown for us days in nutrient solu-
tions with decreasing strontium content and no
031011.11“ O O O O O O O O O O O O O O O O O O

Beet plants grown for 56 days in nutrient solu-
tions containing the highest levels of calcium.
(left) and strontium (right) and with various
combinations of the two elements (center) . . . .

Beet plants grown for 00 days at the hi nest
levels of calciwm (left) and strontium center)
compared with a plant grown in nutrient solution
with no calcium or strontium added (right) . . .

Beet plants grown for dd days in the nutrient

solutions indicated. Note the greater strontium
toxicity when calcium is absent from the nutrient
BOlUtiOn eeeeeoeoeoeeeeeeee

Beet plants grown for 66 days in the indicated
nutrient solutions showing better growth by a low
level of strontium than a low level of calcium. .

The influence of calcium-strontium nutrient solu-
tions on the dry weight of tomato plants treated
for 30 and he days. (Mean of five plants.) . . .

The influence of calciumestrontium nutrient solu-

tions on the dry weight of beet plants treated
for as, 68 and 90 days. (Mean of five plants.) .

vii

19

J45

1L5

51

“5....riavh 1. R . z I. ...n.'., Skill"
cm
i

Ans...)

 

 

11.

12.

13.

15.

16.

17.

18.

19.

20.

21.

LIST OF FIGURES (Cont.)

The influence of various calcium-strontium nu-

trient solutions on the mineral content of
tomato tops treated for2i6 days . . . . . . .

The influence of various calcium-strontium
nutrient solutions on the mineral content of
tomato roots treated for h6 days . . . . . .

The influence of various calciumrstrontium
nutrient solutions on the mineral content of
best tops treated for 90 days . . . . . . . .

The influence of various calcium-strontium
nutrient solutions on the mineral content of
best roots treated for 90 days . . . . . . .

Tomato plant calcium.and strontium.content in
relation to total dry weight after h6 days of
treatment with various calciumpstrontium.nu-

trient solutions. (Mean of five plants.) . .

Beet plant calcium.and strontium.content in
relation to total dry weight after 90 days of
treatment with various calciumpstrontium.nu-
trient solutions. (Mean of five plants.) . .

Autoradiograms of radiocalcium.(Cau5) in bean
plants eeeeoeeeeeeeeeee

Autoradiograms of radiostrontium (Sr89) in bean

plants eeeeeeeeoeeeeeee

Autoradiograms of tomato and beet plants har-
vested 96 hours Egbsequent to treatment with
radiocQICiM(ca')eeeeeeeeeeeee
Autoradiograms of tomato and beet plants har-
vested 96 hours suggequent to treatment with
radIOStrontium (8r ) e e e e e e e e 'e e e
Autoradiograms of temato and beet plants har-
vested 96 hourslfigbsequent to treatment with
radiobarium.(Ba )

viii

Page

60

61

62

63

69

7O

77

78

80

81

82

22.

23.

2h.

25.

27.

28.

LIST OF FIGURES (Cont.)
Page

Autoradiograms of transverse and longitudinal
sections of beet roots showing the distribution
of radiostrontium (above) and radiocalcium.(below)
following isotone additions to the root medium .

Distribution of radidstrontium.(Sr90) in tomato
fruit 36 hours after painting radiostrontium on
thasurface 000.000.000.000... 88

Distribution of radiostrontium (Srgo) in tomato
fruits 80 hours after radiostrontium.application
tOtheplantrOOtBeeeeeeeeeeeeeee 89

Tomato plants typical of those used in Experi-
ment 9 O O O O O O O O O O O O O O O O O O 103

Strontium accumulation by the aerial parts of

tomato plants grown at two calcium levels eight

days after the addition of strontium chloride

the root medium (Mean of four plants.) . . . . . 108

Strontium.accumulation by the aerial parts of

tomato plants grown at two calcium levels eight

days after the addition of chelated strontium.to

the root medium. (Mean of four plants.) . . . . 108

Rates of strontium accumu1a56on in tomato fruits

following application of Sr to the root growing
media of plants high and low in calcium . . . . . 110

ix

I. INTRODUCTION

In plant nutrition most studies with strontium have
been conducted from the standpoint of its chemical relation-
ship to calcium. It was thought, and in some cases demon-
strated, that strontium could partially of almost completely
replace calcium.in plant metabolism. Strontium is not con-
sidered an essential plant nutrient but is an element which
plants will absorb and accumulate in rather large amounts if
it is present.

92'

l
59, Srgo, Sr9 and Sr , is a preduct

Radiostrontium, as Sr
of atomic nuclear fission, constituting about 15 percent of
the fission products (Sl). (Furthermore, radiostrontium is
the one fission product that is easily absorbed, translocated
and accumulated by plants. These facts coupled with the
long half-life of Sr90 (25 years) make radiostrontium possibly
the most serious radioactive contaminant of crop plants.
This study was undertaken to determine by additional quali-
tative and quantitative evidence the magnitude of uptake of
radiostrontium and factors influencing its absorption and
distribution in certain selected horticultural plants. Because
of the chemical similarities of calcium, strontium.and barium,
there is considerably emphasis on the comparative absorption,

distribution and accumulation of the three elements including
their radioactive forms in the pages which follow.

 

.. 31.... fitter: ». £1.54

fr“ “9;

a. a; ...Ial

 

II. REVIEW OF LITERATURE

General

Strontium is an alkali earth metal located in Group
IIA of Period 5 of the periodic table of the elements. Its
nearness to calcium in the periodic table makes its chemical
behavior similar to calcium. While not as common.as some
elements, strontium is world wide in distribution. The hand-
book of Chemistry and Physics (26) lists it as eighteenth
most common element comprising 0.018 percent of the earth's
crust. Odum.(hl) found the average strontium.content of
sea water to be 8.10 milligrams per liter. He also worked
out the world strontium cycle (hZ) and found it to be a
fairly stable one. That is, the amount of strontium.antering
the ocean from the land is balanced by the amount being taken
out of solution by ocean-organisms, and the quantity incor-
porated into ocean sediments is balanced by sedimentary rocks
raised above sea level. This strontium cycle is qualita-
tively similar to the calcium cycle but quantitatively the
8r:Ca ratio is about 1:500.

The metabolism of strontium in the animal organism is
similar to calcium.(52). It rapidly accumulates in.the skele-
ton when taken into the body. It is one of the few products

of nuclear fission that is absorbed by the animal body from
the digestive tract. The essentiality of strontium as a
trace element in animal nutrition has not been established
but its nearly universal presence in the skeletal tissues

of higher animals has been demonstrated by a number of
workers (52, 56, 62). Rygh (h8) concluded that small amounts
of strontium appear necessary in. the nutrition of the rat

and guinea pig. He found that strontium stimulates deposi-
tion of calcium in bones and teeth. Some lower forms of
marine animals and plants contain large amounts of strontium

in certain body or plant parts (hl. 5h).

Historical Review of Strontium Nutrition of Plants .

Early workers claimed that strontium was not absorbed
or translocated. According to Daubeny in 1835 (11;) and again
in 1861 (15) Plants did Int absorb strontium. He attributed
this phenomena to the "vital” activity of the roots whereby
needed nutrients were absorbed and unnecessary elements were
excluded. Colin and Lavison (11) reported that only minute
amounts of strontium could be detected in plants and that
barium was excluded entirely . Later Brenchley (7) suggested
that the chemical methods of Daubeny and Colin and Lavison
may hafe been inadequate.

Nearly all other workers have agreed that strontium can

be absorbed by plants to a greater or lesser degree but opinions

 

h , .
.o.’ .5 ..
.q I. . ' Hl‘ ..r.- J_ _

 

as to its value to the plant, and its relation to calcium
nutrition vary considerably. Some investigators reported
beneficial effects of strontium. Haselhoff in 1893 (22)
concluded with barley, beans and corn that strontium was
not toxic and that it will replace calcium when calcium

is limited. According to Russell (’47) Azotobacter, the
non-symbiotic nitrogen fixing bacterium, requires either
calcium or strontium. Osterhout ((43) noted that either
strontium or barium could perform the same function as
calcium in the soil solution; that of counteracting the
toxic effects of high concentrations of magnesium, sodium
or potassium. He called this a balancing rather than a
nutrient effect. P100001 (31;) also noted this. effect while
studying the antitoxic action of certain nutrient and non-
nutrient elements. Barium and strontium alone were very
toxic to peas and wheat, but in mixtures with other elements
barium inhibited the toxicity of high concentrations of mag-
nesium or potassium, and strontium reduced the toxicity of
potassium, sodium or magnesium.

In the Hawaiian Islands Hence (20) found that sugar
cane filter-press cake contained strontium along with several
other non-essential elements. Poor sugar cane soils contained
less strontium, chromium and zinc than soils which would
support good crops. An excellent cane producing soil was
characterized by the presence of strontium, barium, and

lithium. Vlamis and Jenny (60) investigating a calcium

 

11"; ,Jblfl .I 1.1,IHIIIL'LQIII.
fie. v A
,

 

 

deficiency disease of romaine lettuce, reported that strontium
alleviated the symptoms of the "disease", and suggested stron-
tium could partially substitute for calcium in this crep. A
peculiar chlorosis of Red Elberta peach trees in New Jersey
studied by Wolf and Cesare (66) failed to respond to any of
the normal plant nutrients applied eitheriso soil or foliage.
when they applied strontium chloride sprays to the leaves

they obtained complete correction of the chlorosis within.two
weeks.

Additional cases where strontium has produced favorable
growth responses have been reported by Menargue (36), Scharrer
and Schropp (R9) and Walsh (63) using small grains and legumes
as test plants. In all of these reports the increased yields
were produced only”when adequate calcium.was also present in
the culture medium. They all found a definite toxicity and
yield depression at strontium.concentrations above those
causing favorable responses.

0n the other hand, other early investigators obtained
no favorable plant responses to strontium at any concentra-
tion. Loew in 1898 (32) and 1903 (33) stressed the importance
of calcium in the "calciumpprotein compounds in the organized
particles from.which the nucleus and the chlorophyll bodies
are built up", and concluded from his experimental data that
no other element could replace calcium in this function. He
stated that the abnormal symptoms developed by his plants were

inot just the effects of insufficient calcium.but an actual

toxicity of strontium. Suzuki in 1900 (58) came to this
same conclusion. Voelcker (61) added strontium in several
forms to a "light unproductive soil". Additions of up to
one-tenth percent strontium sulfate, hydroxide or carbon-
ate had no effect upon germination or yield of wheat but
the chloride at one-tenth percent was distinctly toxic.
Strontium nitrate produced an increase in yield but this
was not attributed to strontium.

McCool (3h, 35) and Stiles (55) as well as Loew and
Suzuki mentioned above discussed the effect of calcium
on strontium toxicity in solution culture. They noted that
strontium in the absence of other nutrient elements is toxic
to many plants at very low concentrations. Much higher con-
centrations of strontium must be used to produce toxicity
symptoms when the substrate is a complete nutrient solution
or a soil. They attributed this primarily to the presence
of calcium. Their work indicates that plants have consider-
able tolerance to strontium providing there is adequate
calcium present. McCool (314) found that potassium, sodium
and magnesium are also able to decrease strontium toxicity
symptoms to a certain extent. Hurd-Karrer (27), working
with pairs of chemically related elements, one essential the
other toxic, discussed the calcium-strontium relationship to
some length. Following is her discussion (in part):

"The basic concept of what may be'termed imass

antagonism' is simply that of a mass effect of an
essential element on the proportionate intake, and

"-4“.
[I‘- ' '

aw. it"s...ii £33.. . sari: .1.W.! . flu. I mm

W.

utilization in organic synthesis, of a toxic element

sufficiently similar chemically as to preclude any

considerable selectivity. The total intake of the two

related elements, the one essential, the other toxic,

is presumably determined by the gradient established

by the plants metabolism of the essential one; and the

intake of the toxic element decreases, in consequence,

with increasing availability of the non—toxic one."
Ion differences or root membrane selectivity were not refuted
but it was suggested that control was not good enough to dis-
tinguish between members of close pairs such as calcium.
strontium, potassiumprubidium, phosphorus-arsenic and sulfur-
selenium. Thus it would appear that the damage produced by
a toxic element is in proportion to itslconeentration relative
to the chemically sbmilar nutrient rather than to its absolute
concentration. The report by Collander (12) tends to support
this contention. He experimented with twenty species of
higher plants that had a wide range of calcium.requirements.
His results showed that plants with high calcium requirements
were able to absorb and accumulate more strontium. A char-
acteristic common to all plants was that the strontiumecalcium
ratio in the plant tissue'was of the same magnitude as the
strontiumccalcium.ratio in the nutrient solution. His explana-

tion was that plants are unable to distinguish between the

two and that absorption is proportional to quantities present.

Strontium Nutrition Studies Using Radioactive Isotopes

Jacobson and Overstreet (29) noted that the principal
long-lived products of fission (Sr, Y, Zr, Cb, Ru, Te, Cs,
Ba, La and Ge) were not essential to plant life and there-
fore have been studied very little. In their investigation
they found plant roots could successfully compete with soil
colloids for many fission products. However, most of the
elements apparently remain adsorbed on the roots, or, if
absorbed into the roots, are only sparingly translocated
to the aboveoground plant parts. The single exception is
strontium.which is easily absorbed and translocated to the
stems and leaves in relatively large quantities. lfith the
dwarf pea they found that strontium content in the root was
ten times greater than the surrounding soil. The leaves
and stem were slightly less radioactive than the roots while
seeds showed very little strontium accumulation. Autoradio-
grams of pea leaves showed the highest concentration of stron-
tium in the veins.

Jacobson and Overstreet studied the effect of radiation
injury on plants and found that activity levels of one tenth
microcurie per gram of soil were sufficient to cause pronounced
radiation injury over a three-month period. Spinks, Cumming,
Irwin and Arnason (53) also studied radiation injury. They
reported the lethal dose of either Sr9o or P32 for wheat,

barley and sunflower seeds was approximately l.h microcuries

 

 

l 9!
4 a-
-,-- (2:.
I I .‘V‘. .

(\"3‘0‘rn 1";

,‘eMle‘l D“.
(spam-‘1 r.
L...» C .‘.

“I

.,.. . t .

.Is‘u on y e

sane-nous. ~-‘
.

Hes celc‘;

«a

rue-22min:

\

0"“. Ir...

.'.‘ ." ‘s.‘
V

:1 f'ce‘ H

Oi...

N

‘a

"'M'. H
' V or?”

5. a.

tie said":

5““ SENT:

per seed. Blume (6) was unable to demonstrate distinct
radiation injury from P32 at levels as high as three-tenths
microcurie per gram of soil. Of interest along this line,
Biddulph and Cory (h) suggest fission product radioactivity
causes calcium deficiency. Purslane, Portulaca glpracgg, in
revegetating the denuded areas of Eniwetok Atoll, showed a
striking inverse relationship between total calcium content
and fission product radioactivity. These authors believed
fission product radiation injury results in a disruption of
the calcium absorption.mechanism.

Neel, Gillooly, Olafson, Nishita, Steen and Larson (38)
grew several crop plants in soils artificially contaminated
with various fission products. The found, as did Jacobson
and Overstreet, that strontium is absorbed and translocated
in much larger anounts than cesium, ruthenium, cerium and
yttrium. The observed differences in absorption from.the
various soils was somewhat correlated with the clay type
present. The authors suggest strontium.is more easily absorbed
because it is less strongly adsorbed on the soil colloids. 0f
the crop plants studied, bean and radish accumulated the most
strontium, barley the least, and lettuce and carrotivere in-
termediate. The highest Specific activities were found in
leaves. The corresponding roots were somewhat lower in

activity and the seeds very much lower.

jag: steer. 3.14:.5.“ ‘.1li.?. L4

Elk.

 

lO

Rediske and Selders (#5) added radiostrontium (Sr90)to
the soil solution of young Red Kidney bean plants and grew
the plants for extended periods of time. They found there
was no significant redistribution of strontium once it was
mobilized in a leaf, and the total amount accumulated by a
leaf was proportional to its age. Each plant tissue had a
maximum total amount that would accumulate for a given nu-
trient condition. The adsorption of strontium.during a four-
day treatment period.was proportional to its concentration
in.the nutrient solution up to 100 parts per million when the
calcium concentration was constant at 1&0 parts per million.
The strontium content of roots was higher than the tops be-
cause of a high proportion of adsorbed strontium. This ac-
cumulation of strontium on the roots decreased as the acidity

of the nutrient solution increased from.pH 7 to pH h.

Studies Concerned with Foliar Absorption of Nutrients

The literature on foliar absorption and subsequent distribu-
tion and utilization of nutrients by plants has been summarized by
wittwer and Tukey (6S), Ticknor (S9), and Norton (hO). In
general it has been found that rout:- applications of phos-
phorus, nitrogen and potassium.as well as severalmicro-
nutrients can be beneficial to the plant. All of these ele-
ments are apparently easily translocated throughout the
Plant following absorption by leaves.

t.
knit ”V

warn-r

7‘

'1 .

 

 

 

Calcium does not appear to be as easily translocated
from the site of foliar application as other nutrients.
Downes (16) found slight downward (basipetal) translocation
from the leaves to the roots of the onion but Norton (hO) working
with the strawberry found little or no movement of CauE
from treated leaves. Haynes and Robbins (23) and Ririe and
Toth (A6) demonstrate another pecularity of calcium trans-
location using the split-root technique with tomato plants.
When the root system of a tomato plant was separated into
two separate culture media, calcium did not move from one
_half of the roots into the other half. One part of the root
system.may die from.lack of calcium even when the other side
is adequately supplied.

The peanut plant has provided another example of limited
calcium movement. Harris (21) and Bledsoe, Comar and Harris
(5) demonstrated a calcium.aupply in the pegging zone is
necessary for fruit development and normal yields. IsotOpe
studies with Cali5 showed the calcium absorbed by the plant
roots is not translocated to the developing fruits once they
are established in the ground. The fruits must absorb their
own supply of calcium.

The report of Wolf and Cesare (66) mentioned earlier, is
the only study located concerning the foliar application of
strontium. They reported the correction of a peach.1eaf

chlorosis by strontium sprays. The correction was obtained

jg. rate... a. .fl.4.l..i|un1llu.J
.. . "I
a. I... (g .
r

12

only on the branches sprayed indicating there was little or
no strontium translocation to branches not sprayed.

The meager evidence available indicates the downward
movement of calcium, and possibly strontium, from foliar

application is either very limited or does not occur at all.

13

III. THE PROBLEM FOR INVESTIGATION

It has been demonstrated that plants will absorb stron-
tium.from.a soil or nutrient solution. In small amounts it
does the plant no harm.and may even promote growth. In large
amounts strontium produces a toxicity which varies in magni-
tude depending en the plant species and the relative abundance
of other available nutrients. Part of this investigation is
concerned with the maximum.strontium.absorption by tomato
and beet plants, the effect of plant calcium.eontent upon
strontium uptake, and the effect of high plant strontium on
the absorption of other plant nutrients.

Trace amounts of radioactive strontium in crop plant
tissues represent a health hazard from radiation rather than
from the chemical element itself. Therefore the absorption,
translocation, and subsequent accumulation of small amounts
of radiostrontium in plant tissues will be studied. Equally
as important as root absorption is the study of absorption
by the above ground plant parts. Recent studies have shown
that many micro-nutrient elements and some macro-nutrients
can be supplied to plants, including the roots, by applying
them.to the foliage. This investigation centers on,a study
of the absorption and translocation of radiostrontium.by above

ground portions of plants.

IV. MATERIALS AND METHODS

General

All experimental work was carried out in the greenhouse

during the years 1951, 1952 and 1953. The plants used were

tomato, Lycopersicon esculentum, variety Michigan State Forcing;

beeh,Beta vulgaris, variety Detroit Dark Red; and bean,

Phaseolus vul aris, variety Michelite. Plants were grown in

sand or gravel culture using the nutrient solution recommended

by Hoagland and Arnon (25) the composition of which is given

below. All nutrient carriers used were reagent grade or C?

salt! 0

Nutrient

Nitrogen
Phosphorus
Potassium
Calcium
Magnesium.
Sulfur
Iron
Boron
Manganese
Zinc
Copper
Molybdenum

Hoagland Solution #2

Concentration (ppm)

210
31
23h
160
he
6h
0.8
0.5
0.5
0.05
0.02
0.01

Nutrient Carrier
NHuHZPOh, KNOB, Ca(N03)2
NHhHZPOh
KNOB
Ca(N03)2
M380“

"880,4

Ferric ammonium.citrate
H330

MnCl2 ° uHZO

ZnSOh ° 7H20

CuSOu 0 5320

HéMeoh - 320

15

This nutrient solution as prepared in 18 liter lots in
the greenhouse had a specific conductance of 165 mhos x 10-5
and a pH of 7.h. The pH of distilled water provided varied
from 6.5 to 7.5. A specific conductance of 165 mhos x 10”5
is equivalent to an osmotic pressure of 0.59 atmospheres
which is well within the limits recommended by Stout and
Overstreet (S7) for nutrient solution culture.

Ca1cium.nitrate was withheld from.the nutrient solution
when a low calcium level was desired. The nitrogen level
was maintained by adding an amount of ammonium.nitrate equiva-
lent in nitrogen to the nitrogen in calcium nitrate omitted.
The plants for whole-plant autoradiograma were grown in regular
greenhouse sand. All other plants were grown in either Flint-
Shot sand1 or Vausau Quartz #82. Beth.were high grade quartz
and very low in plant nutrients. Wausau Quartz was used when
roots were to be chemically analyzed because the coarse particles
could be easily separated from.the roots without excessive
leaching. Plants were grown in either six-inch clay pots or
two gallon glazed crocks, depending on the size desired. The
clay pots or glazed crocks were placed in a pan filled with
one to two inches of nutrient solution. The solutions were
changed regularly and the sand-occasionally leached with dis-
tilled water to prevent salt accumulation. More specific

descriptions of the culture conditions of various experiments

 

l. Obtained from.0ttawa Silica Sand Co., Ottawa, Illinois.

2. Obtained from.American Graded Sand 06., 29h0-50
Ashland Ave., Chicago, 13, Illinois.

16

will be given in the discussion of each. In the one case where
field grown plants were used, samples were harvested from sev-
eral locations at the end of the 1953 growing season and analyzed

for strontium and calcium.

2. Chemical Analysis

A Beckman Quartz Spectrophotometer with hydrogen flame
attachment was used to determing the strontium, calcium, po-
tassium.and sodium content of the plant samples collected.

The technique used was based on the method of Hinsvark, Witt-
wer and Sell (2h) but considerable modification was made since
a hydrogen instead of acetylene burner was used and the sub-
strate was changed from.ten percent to one percent perchloric
acid. Their determinations were made on pure salts of calcium,
strontium and barium using concentrations much higher than
those found in plant tissue unless separation and concentration
techniques are used. The high concentrations in their solu-
tions permitted the use of very narrow slit widths and conse-
quently minimized flame background and interference by other
ions. The great number of samples and the lunited amount of
tissue available made separation and concentration techniques
impractical in this study. Consequently a method was devised
whereby calcium.and strontium could be determined in fairly
dilute solutions in the presence of the other plant ash consti-

tuents, principally potassium, magnesium.and sodium.

17

The plant tissue samples were prepared for analysis
using a modification of the A.U.A.C. Methods of Analysis
(1) for plant ash constituents. The following procedure
was employed:

Plant tissue samples dried at 70° C were ground in

a Wiley mill using a no mesh screen. One gram.or two

gram.samples in duplicate were weighed into Lo cc por-

celain crucibles and ashed at 550° C for 10-12 hours.

When cool the ash was wet with distilled water and then

dissolved by adding about two mdlliliters of (1+3)

perchloric acid (Baker's analyzed reagent grade, 70

percent). The ash solution.was heated on the steam

bath for 30.minutes and filtered while warm through

Watman No. no filter paper into a 100 ml. volumetric

flask. The filter paper was washed several times‘with

warm one percent (by volume) HClO . When cool the solu-
tion was made up to volume with o e percent HCth and
transferred to a four ounce screw cap bottle for storage
and subsequent analysis.

The substrate for all samples was one percent (by volume)
perchloric acid. The usual dilution factor was onelgram.of
dry plant tissue made up to one hundred milliliters but with
tissues low in ash, such as tomato fruits and beet roots,
as much as four grams of dry tissue was used. higher con-
centrations tended to plug the capillary tube of the hydrogen
burner. All plant samples were run in duplicate, the values
reported being the average of the'two determinations.

Two thousand parts per million stock solutions of the
individual.metals were obtained by neutralizing reagent grade
carbonates with concentrated perchloric acid and making to
volume with one percent perchloric acid. Stock solutions

were diluted to various concentrations to obtain standard

 

q,iblott4§'. HIE. }
.._

..
...

 

 

18

curves on the flame photometer (Figure 1). Percent trans-
mittance values for the various elements in plant samples as
well as in standard solutions were obtained using the condi-
tions shown in Table I. All determinations were made with
the spectrophotometer selector switch set at 0.1 and a 10,000
megohn phototube resistor in the circuit. The operating oxygen
pressure was held constant at ten pounds per square inch.
Standard curves were initially made using a fuel (hydrogen)
pressure of 6.5 pounds per square inch but in order to repro-
duce the standard curve from day to day the fuel pressure had
to be varied within the lhmits shown in Table I. Under these
operating conditions there was no flame background in the deter-
minations of strontium, calcium, potassium, and sodium,

The elements causing interference with the flame intensity
are also listed in Table I. Brown, Lilleland and Jackson (8, 9)
corrected for flame interferences by adding an average amount
of the interfering elements to the standard solutions used for
making reference curves. This method is apparently satis-
factory for field grown plants where the‘variation in composi-
tion is not too great and the interfering elements are always
present in the plant tissue. In the present study, strontium,
the main element under consideration, varied from 350 to 0.0
parts per million in the solutions analyzed. The mean of two
such.widely different values, used as the average strontiwm

interference for all samples, would cause considerable error

 

 

 

 

 

v. 1 .r....|,‘ for, ,. n

f 3f
3;

 

 

 

 

 

 

 

 

 

‘E

19

.Esaoawo may .ESapflonpm on .ESaUOm Amv .Efiammepom «my
Mo coauwnpqeocoo one hpfimsepcfi eEmHm awesome mfinmcofip
uwaen ens .hnpeeouoma madam now mo>nSe mpmoawpm .H .mwm

 

 

 

 

 

 

 

 

 

 

 

8354(0 .Iam 83:.zoth .Itm
omw amt 0mm cont OWN
H J a 0 % q a 0 an
i i
a 8
V V
N N
S S
m m
I. W00 l.
i i
m w
..... a
:3.
Sax—Om in... 8:.mm4hom its
00m 0 N 000. 000. 000
"w MW e n u u n .c x
u h
V V
w. m.
m m
I.
I00 m '0“ u
u w
m a

 

 

OO.

 

<t

 

 

 

 

 

 

#1.: iiimeli I 34%an
4 . .. . . lit-K

a...

{cal-.1...

 

 

 

 

 

 

countess is:
902 8” 8m «6&6 cog—co? 3:. 5.2.0 $8 538
Sunfish .
23:38 8H 08 3.70.0 p333... e2 0E6 .20 533
A55 ow
obopev gwpom
550 To
23:38 03 8* ages sameness eon 08.0 .me 53:88
3oz on com onus.» venom:- eos ”No.0 0.5. 5:32.—

 

ooguouuopcu unevnuom mom. A8323 205 ewe—5e

093E LCM MGHPBUD cum“ mgflv BO“ chav Ahogn—Hnflg Angogflfifld—flv
mawesao oofivvgawa 0.8095 0.5395 wauuvem

385a please m2. Because aufinaaafim 3338: has; £3 59.3 or; nausea

l

 

max 52.5 E Hem—axon wags—m Angm ho zohh¢gfimn Ohmamfiosgm mafia mm." 5: amp WSHHHQZQ

H “ma—EH

 

 

.
l I
'w‘ln

. .
nu... .

l I
“1" ,
.... ~

"Iv-a
vul.‘

‘I-Iu

CI
‘n.. “

.... d

 

5‘.

‘ u
a... ‘

u.“‘

.
)

_..._.—_

{\J
t"

in the calcium determinations. The interference problem was
solved by applying individual corrections for the various
interfering ions. The corrected percent transmittance could
then be converted to parts per million by using the standard
curve.

Because of the high flame intensity of potassium as
well as its high concentration in the solutions, the slit
width.was very narrow. Strontium, calcium, magnesium.or
sodium did not interfere with the observed transmittance of
potassium, hence its concentration in an unknown solution
could be read directly from.the standard curve (Figure la)
without correction. Potassium.however, interfered with both
strontium and calcium. Strontium.interfered with the flame
intensity of calcium, and calcium.interfered with strontium.
Magnesium.at any concentration and sodium below fifty parts
per million did not cause any appreciable interference. Above
fifty parts per million sodium.interfered slightly with stron-
tium.flame intensities. All samples from.greenhouse grown
plants contained less than thirty parts per million of sodium,
Only samples from.field grown plants required a sodium.cor-
rection for strontium transmittance. All interferences caused
an increase in flame intensity of the element being determined.
Thus the correctione'were subtracted from the observed percent
transmittance to find the transmittance of the element being

determined. Where two elements such as calcium.and potassiwm

22

interfered in the determination of strontium, standard solu-
tions were made up containing both interfering elements and
the resulting interference was found to be nearly equal to
the sum of their individual interferences. That is, the two
interferences were essentially additive (Table II).

To correct for interference, several concentrations of
the interfering element were added to each of several concen-
trations of the element being determined. The deviations of
these percent transmittance values from.the transmittance of
the element alone are shown in Table II, using strontium as
an example. Table II shows that calcium.interference is es-
sentially independent of strontium.concentration but that in-
terference by potassium depends not only upon the concentration
of potassium.but also on the concentration of strontium, Thus
two types of correction curves are necessary as shown in
Figure 2. The potassium content of each solution must be de-
termined before a potassium correction can be applied. The
potassium.correction for calcium transmittance was like Figure
2-1 except the corrections were approximately one-third as
large. Strontium.interference corrections for calcium were

similar to but slightly greater than those shown ionigure 2-8.
The concentration of the element in parts per million

was obtained from.the standard curve (Figure 1) after the
corrected percent transmittance was determined. Parts per
nullion in solution was then converted to an expression of

plant composition, either percent dry weight or milligrams

TABLE II

INCREASES IN THE PERCENT TRANSMITTANCE OF VARIOUS

CONCENTRATIONS OF STRONTIUM CAUSED B! THE FLAME
INTERFERENCE BX VARIOUS LEVELS OF POTASSIUM AND CALCIUM

 

Interferin Element Strontium concentration (ppm)
(ppm. 0 50 100 200 300
(% Transmittance increases)

0 K 0.0 0.0 0.0 0.0 0.0

50 K 0.2 0.9 1.2 107 202

100 K O.h 1.1 1.8 2.2 3.6

250 K 0.5 1.5 2.h 3.0 h.0

500 K 0.8 1.9 3.0 3.5 5.0

750 K 1.1 2.2 3.h h.5 5.2

1000 K 1.3 205 307 500 509

1500 K 1.6 --- h.0 5.6 6.9

0 Ca 0.0 0.0 0.0 0.0 0.0

50 Ca 002 000 -001 -002 0.0

100 C‘ 001‘. 0.3 0.3 -002 0.0

250 Ca 1.0 1.0 1.0 1.0 O.h

500 CE 1.8 1.9 203 108 201

700 Ca 2.6 C‘- 3.1 205 2.8
100 K 4' 100 Ca 203
250 K + 100 Ca 2.?
100 K + 250 Ca 2.9
500 K + 250 Ca 3.9
1000 K + 500 Ca 5.7

21)-

 

 

TRANSNITTANCE

CORRECTION (96)

STRONTIUM

TRANSMIT TANCE

STRONTIUIA

CORRECTION (%I

 

 

A POTASSIUM
COMO. (PPM)
'3 1 I500
I000
-6 .1
500
'4 d 200
loo
-2‘
r I 1
0 50 l00

OBSERVED

TRANSHITTANCE OF STRONTIUN (90

 

 

-2 ‘
-' q
I j
0 50 I00
CORRECTED TRANSMITTANCE OF CALCIUM (V-I

 

Fig. 2. Corrections applied to the observed
strontium transmittance to account for flame
interference by (A) potassium and (B) calcium.

 

 

 

_.—_ _ a-‘

_ —.—~———~“-—-‘-‘_ _.

 

 

 

.11 a ’1 a!

f!

I “f f." D

I... m I.)

of element per gram of dry tissue. All the determinations
of strontium, calcium, potassium and sodium for Experiments
1, 2 and 3, as well as the control plants of Experiments 7,
8 and 9, were made by this method.

Spectrographic analyses of Experiment 2 samples for
magnesium, phosphorus, iron, manganese, copper and boron were
made by the Department of Agricultural Chemistry. The method
was an adaptation of the techniques described by Churchill
(10), Cuettel (l9), and Mitchell (37), and is briefly as

follows:

Two grams of oven dried plant tissue were ashed
in the muffle overnight at 600° C. The ash was wet
with 2 ml. of 5 percent LiCl, which provided the
lithium internal standard, and then dissolved by
adding Baml. of H01 (1 + 1). 0.025 ml. aliquots of
the dissolved ash were micrOpipetted to the polished
ends of six carbon electrodes which were then dried
rapidly under infra red heat lamps. At the same
time electrodes of the referee samples were prepared.
Pairs of electrodes were placed in water cooled ig-
nition chamber of a Hilger Large Quartz Spectrograph
and subjected to a controlled A. C. spark for sixty
seconds. Nine unknown.samp1es (in triplicate) and
the four referee samples were run on each spectro-
graph plate (Kodak spectrum analysis #1) which cov-
ered the spectrum range 2h5.0 to 350.0 millimicrons.
After photographic development in D-l9 developer,
the density of the various lines were read using a
Jarrell-Ash Recording Microphotometer. The wave
lengths of the spectrum.1ines used were: boron, 2h9.7;
-phosphorus, 253.5; magnesium, 277.8; manganese, 29h.9;
calcium, 300.6; lithium, 323.2; and copper, 32h.7
millimicrons. The intensities observed.were then con-
verted to the logarithms of the relative intensity
(Log R. I.) based upon the intensity of the internal
lithium standard. Standard curves, straight lines on
logarithmic paper, were made by plotting the log R. I.
for the referee samples against the known concen-
tration of each element in the referee samples.

 

 

 

 

 

 

.u

I" ‘
I“..t’ an.
n
. q
. »v-
a... PI' -
..- u. .n
P; ‘

stmr:

'5'.“ Es

"‘1:”r~r

nor-u..V ..

e‘. «‘I

vzq‘-

Test

‘Vwe:

:i-.'
e.“

a,“

R‘r.

“A,
..

‘w

26

The referee standards were leaf samples of tree fruits
(apple, cherry, peach and citrus) in which the six elements
had been previously determined with considerable accuracy.
The Log R. I. of the unknown sample was referred to the
standard curve to find the percent composition of each ele-
ment. Each value represents the mean of triplicate deter-

minations on one plant ash solution.

3. Autoradiographic Methods

Autoradiograms of whole plants were used to evaluate the
gross intake and distribution of foliar and root applied
radioisotopes at various time intervals following treatment.
Plants used were tomato, beet and bean, and the radioisotopes
studied were CahS, Sr89, Sr90, and Balho. Sections of beet
roots and tomato fruits one and one-half to two millimeters
thick were also used. These were prepared for exposure to
the film either by quick freezing or by drying under heat and
pressure. The X-Ray film used was 8 x 10 incthodak Blue-Brand,
or Kodak No-Screen, which was exposed for various time inter-
vals depending upon the radiation intensity. Evans (17)
points out that X-rhy emulsions are the most sensitive of all
emulsions to beta and gamma radiations but the grain is
large and irregular. however, for gross studies such as
these, their resolving power was adequate. Plants were treated

when they were of such a size that the entire plant including

roots could be pressed on an area 8 x 10 inches.

 

 

.
l'!
i

 

 

 

Mane,

......._...¢— -

‘0
ii'QV“

l"“-l.!~’
' u.

“ I. an

n... ..

:u...,..

~..~.¥
e“: :9

27

Twenty-four autoradiograms could be prepared simul-
taneously using the method of Wittwer and Lundahl (6h).
Exposure times varied from a few days to several weeks de-
pending on the level of radioactivity. The exposure for
each group of plants was kept constant so that the impres-
sion on the film would semi-quantitatively represent the
amount of radiation present in the respective tissues from
the different treatments. After exposure the films were

processed in X-ray developer and fixative.

h. Studies Using Radioactive Isotopes

All radioactive isotopes used in these experiments
were obtained from the Atomic Energy Commission at Oak
Ridge, Tennessee. Early shipments of radiostrontium.were
Sr89 containing 5 - 10 percent of Sr90 and 190, subsequently
referred to as Sr89. Later shipments were received as Sr90
with a radiochemical purity of 99 percent. Both isotopes
were received as the chlorides in weak H01. Radiocalcium
(Cans) was received as CahSClz in weak H01, and radiobarium.
3’2 in weak HNOB. These

isotopes were used to study the absorption and subsequent

(Baluo) was obtained as Ba1h0(N0

translocation of these elements following direct leaf or
fruit application or addition to the root media. Treating
solutions were prepared by adding tracer amounts of the

radioactive isotope to solutions of the stable isotope.

21‘“ ~ w—«Mlfilfl;'¢fi;fi_&*“‘d

 

 

ant—s _ ..,c——— .

A... . .—_

. h
.29 (Is-EA

v

'I . ,-
"9|. '- S
CI‘U‘I II”

n.

were

E. " RHAAH‘

“V...

A.

m) “I ‘ ‘

neat“ ..

‘t": "r .
““‘U I»...

nv
u‘._

u ._
I L.
"h 4..

"Hp-r...

I‘m-u ..

‘\

':~‘- "in

skv u.‘
I

":a

I .5 av

‘.

‘. .-

le.

e
C‘-

n.
-‘<
‘s

.a

'A

\-I\
u

‘a

28

The usual concentration of radioactive isotope in foliage
treating solutions was one microcurie per milliliter but
there were some exceptions. Specific activities, expressed
as microcuries of radioisotope per milligram of stable ele-
ment, will be given with each experiment. For root treat-
ments the foliage treating solution was diluted several-fold
with water to assure complete distribution in the sand.

Plants were grown in sand or crushed quartz in the
greenhouse as described earlier. When of sufficient size
they were randomly selected for treatment. Root treatments
were applied by pouring the isotope solution on the sand
around the stem. The enamel pans in which the pots or
crocks were placed were not emptied between treatment and
harvest time. Leaf applications were made by dipping the
leaves in a beaker or pan containing the isotope solution.
Tomato fruits were treated by painting the isotope solution
on the surface or, in one case by injecting it into the
fruit with a hypodermic needle. A suitable wetting agent
was added to the dipping solutions. The specific conditions
of plant growth, nutrient solutions and treatment application
will be given with each experiment.

Plant parts were harvested after the specified treatment
period, fresh weights determined, dried at 70° c, and then
weighed again. Except for Balho samples, the dry tissue was
ground through a h0-mesh screen in a Wiley mill and then

29

thoroughly mixed. Radiobarium samples were broken up by
hand, ashed, and the ash was taken up in dilute HCl. Barium
was precipitated as the carbonate, filtered,and the precipi-
tate transferred to round, flat bottom tin boxes.1 Radio-
calcium samples were prepared by weighing 0.2268 gram of
tissue, equivalent to twenty milligrams per square centimeter,
into a tin box. The tissue was spread uniformly over the
bottom of the box and then ashed in the muffle furnace.
Radiostrontium samples were prepared for counting merely by
uniformly spreading a weighed amount of ground tissue over
the bottom of a tin box or Coors capsule.2 The dry plant
tissue was counted without further treatment.

Regardless of the method used to prepare samples for
counting, self-absorption curves were made for each isotope
in each different geometry using the method of Schweitzer and
Stein (50). Sample sizes for counting were chosen so that
self-absorption would be negligible. Thus self-absorption
was avoided rather than corrected for by calculation. Where
corrections for half-life were necessary, the formulas given
by Kamen (30) were used. This was ordinarily avoided by count-
ing the treating solution reference samples at the same time

as the plant samples and making all counts of comparable

— A

——

1. Labelstik tin boxes, gold lacquered, oneghalf ounce
Size. Obtained from.George D. Ellis and Sons., Inc., Myers
Manufacturing Division, Camden, N. J.

2. Coors glazed porcelain ashing capsules, four centi-
meters in diameter, one centimeter high, with flat bottom.and
Straight sides. Obtained from.Central Scientific Company,
1700 Irving Park Road,Chicago, 13, Illinois.

I 2‘
.m :g 'I '
.

use».
.

:I'II‘ IV!

an... A“

O
't““'£"c
'uqu ~o-.-.....

. . ‘
.I’v I‘.“

r
'x
z.“
l;
uni

'-‘x" “I

 

B
9
L4
g"

F

I

I

(WI

”I“ Aug _ .

to.

I."

*V- e
..:i ‘:"

's‘n" .“

""In...

‘ I
‘-‘r~"I

I
I
'“'~.a'.‘

 

'Ia

30

I

samples within a short time interval. Samples were counted
either in a Tracerlab Model SC-lB Autoscaler or a Nuclear
Instruments and Chemical Corporation, Model 172 Ultrascaler.
Both instruments were equipped.with shielded counting chambers.
The final data are expressed in terms of micrograms of
the element, per‘gram.of dry tissue, derived from the isotope
treatment. Values were calculated as follows. The treating
solution was originally prepared to contain a certain molar
concentration of the element under study. From this the hump
ber of micrograms of the stable element per milliliter of
treating solution could be calculated. The weight of the radio-
isotope was neglected because even Sr90 with its long half-life
weighs only 6.31 x 10'3 micrograms per microcurie. The counts
per minute per milliliter of treating solution were obtained
by counting the reference samples. Dividing the counts per
minute per milliliter by the micrograms per milliliter gave
the number of counts per minute representing one microgram of
the element. All plant tissue counts were converted to counts
‘per minute per gram.of dry tissue. These values divided by
the counts per minute per microgram of the element equal the
value for micrograms of the element, derived from the isotope

treatment, per gram.of dry tissue.

|"‘=‘V L ‘|
I.I-a¢a - . \-
ASL-I -'."

:33

if N“!- g

l’a‘iO‘aa d

I
in

 

 

I
, “Ca.
5 al.-
1
Lfl
Ts?
I .‘h
I " ME
I
1:
I
I
I
I N, .
1 3‘3“
.‘g‘
i u
| :“:\
J a
.. ‘

vV1

pl)
I.

31

V. RESULTS

The experiments may be separated as follows. Those
concerned with the absorption and translocation of strontium,
calcium and barium as indicated by, (1) chemical analysis,

(2) autoradiography and (3) radiation counting.

A. Absorption and Translecation of Strontium.in Tomato and

Boot Plants as Determined by Chemical Analysis

Objective
To determine the quantity of strontium, calcium and
barium absorbed by tomato and boot plants grown at two levels

of calcium when the treatment period is short (h days).

Materials and Methods

Seeds of the two vegetables were planted in Wausau
quartz #8 on March 20, 1952. Seedlings were transplanted into
six inch clay pots on April tenth. A two-inch square of brass
window screen prevented loss of quartz through.the drainage
hole. Each pot was placed in a two quart enamel pan filled
with.nutrient solution. All plants were grown in full hoag-

land's solution until May 20, a period of forty days. At

 

-..- _.'

I.-

d a
(I‘,

32

this time the 56 most uniform plants of each crop were se-
lected for treatment and divided into two groups. One half of
the plants were continued on regular Hoagland's solution; the
other half were given a minus calcium nutrient solution.
hereafter the two groups of plants will be referred to as
"high Ca" and "low Ca" plants.

These nutrient conditions were continued until appli-
cation of treatments on May 31 and June 1. At the time of
treatment tomato plants were three to four feet tall and
had a few small fruits on the second cluster. The first
cluster of flowers did not set fruits. Beet plants were
12-lh inches high and had a root diameter of one and one-
half to two inches. All plants were normal in appearance.
Pots containing plants to be foliage treated were completely
filled with sand and then covered with corrugated cardboard,
held in place with Scotch tape, so that plant and pot could
be inverted without disturbing the roots.

The foliage treating solutions consisted of 0.h percent
calcium chloride (0.0272 M) or chemically equivalent amounts
of strontium or barium chlorides. Actual amounts ofthe three
elements in dipping solutions were 1.09 grams Ca per liter,

2.39 grams Sr per liter, and 3. 75 grams Ba per liter. Triton
8-19561 was added as a wetting agent. Tomato plants were
‘marked above the sixth leaf with a ring of absorbent cotton;

_‘

1. Obtained from.Rohm.and haas Company, Philadelphia,
Pennsylvania.

33

the stem, leaves and shoots below the mark being designated
as "lower foliage", and everything above the mark "upper
foliage". The upper foliage of tomato plants and the entire
foliage of beet plants were dipped in and thoroughly wet by
these solutions. Tomato plants were laid on their side and
boot plants were inverted until the dipped portions were
thoroughly dry. Each treatment was replicated four times.
Treatments to the root media consisted of adding 160
ppm of calcium or chemically equivalent amounts of strontium
(350 ppm) or barium.(5h9 ppm) as the chlorides to the regu-
lar "high calcium” and "no calcium” nutrient solutions. The
only change made in the basic nutrient solutions was to sub-
stitute M'gCl2 for the ugsoh with barium treatments to prevent
the precipitation of BaSOu. The six groups of plants and
their respective root treating solutions were placed in six
large pans 50 by 27 inches and h inches deep, each pan holding
36 liters of nutrient solution. No water or additional nu-
trient solutionwwas added during the four day treating period.
All plants were harvested after 96 hours of treatment.
Samples were dried initially at 50-60°C in a large fOrced
air dehydrator and finally in a constant temperature oven at
70°C. Dried samples were weighed and then ground in a Wiley
mill using a hO-mesh screen. Two gram.samples in duplicate
were ashed, taken up in one percent perchloric acid, and anal-
YZed for calcium, strontium.and barium.on the flame spectro-

phO tome ter a

f.‘ h.

m. i" a

V" '5 a

n.

 

 

- 'v
0.1 r ‘
9“ 6.... n‘

,' I
s s ‘u
“'5

I»... . g.

.h
' s.
D
I;

no.‘.

1‘ ‘A
H. “V 1

e.‘ ..
Ifi. I“

b-‘

'
5“ y“

|
A...
p
I. 5‘

."s
‘»8-

 

3h

Results

Results of the strontium treatments are shown in Tables
III and IV. These data show that there was considerable dif-
ference in calcium content of the "high Ca" and "low Ca" plants,
with the most marked differences being in beet roots and the
6 upper foliage and roots of tomato. Tomato plants accumulate
a higher concentration of strontium.in leaves and roots during

a four-day period than do boots. The high calcium tomato

gnu-awn I.I.—’.i- . ins... _ ——."'
r

plants took up more strontium than.the low calcium plants
while the reverse was indicated for beets. There was little
or no downward movement from.foliage applications to either

tomato or boot.

Calcium analysis of the calcium treated plants showed so
much variability than only trends could be noted. High cal-
cium.plants appeared to take up as much calcium from root
treatments as low calcium plants. There was no evidence of

downward movement from foliage applications.

.. 5!

Very high calcium and potassium interference combined
with a high flame background prevented a valid determination
of barium.by the flame photometer method used. There was one
interesting observation on the soil treatment of tomato with
barium. High calcium.plants showed no vixible effect from
5&9 ppm barium in the nutrient solution but low calcium.plants
were severely affected. Wilting of foliage began on the third

day of treatment and by harvest time all four plants were comp
Pletely wilted and their roots were dead or dying. Low cal-

¢1um.beet plants were not affected.

 

35

bl.
e

‘ birth 4.:

 

 

 

00.0 3.0 3.0 013 8 :3
3.0 H0; 00.0 00.3 8 mean ”23.0
owcnnou
«0.0 3.0 as: $.33 8 :3 033:8
8.0 2.8 S.” 00.: 8 sea 3 03a? ham
2.” 08.0 330 «0.0a 8 :3 308 a»
8.0 80.0 8.0 0...: 8 sea 83.34
am .Emfi do .Ewfi um .58 so is
poem amazon cabana
00.0 2.; 8.0 2:. .0 03. 8 :3
00.0 2.2 8.0 00.: 8.0 3.2 8 some Housed
00.0 2.» 00.0 00.0 on.“ 3.0 8 :3 09.28 been
00.0 00.2 00.0 8.3 N0.” 80.2 8 non. 0» 033% 0.3.8
«08 03. SJ s10 8.0 008 8 :3 .88 3.
e0.» 03: as.” «0.3 8.” 3.2 8 :85 8:92
um .59: do 59: am .3? 8 .3»... am .8».— so .awfl magnum 08532059
poem owoamom noted owning some: escapes: 538.3% no.6

 

 

3 one gram 00:75

183339: .Bou no 808 I 2.6:» 5.3 no anew non 25.53:!

.3563 no 955..— 33 024 mag 84. En 92¢ 032 may.

no Ea..— sz @908 mun. Mm gnazaam n5 EH03 mo Snag—man and gammOma Nun.

HMH mafia

 

 

jui‘wna r 1‘s... .4

It'd—13'“

I i
4“."‘5‘.

EV. Pu...

TABLE IV

TOTAL STRONTIUM ACCUMULATED BY THE ROOTS AND LEAVES OF THE

TOMATO AND BEET AT HIGH AND LOW LEVELS OF CALCIUM

(Milligrams for total plant organ - mean of four replications)

 

L
:.

Strontiwm

 

 

Nutrient

Upper

Lower

 

 

0
rep Treatment Status Foliage Foliage Root
mam 81‘ mam Sr mam Sr
Applied High Ca 65.10 37.88 2h.53
to roots Low Ca 33.79 33.99 18.68
TOMATO Applied to High Co 63.52 0.18 0.00
upper Low Ca h7.38 1.98 0.03
foliage '
contrOl High Cu 0.00 0000 0000
MW Ca 1031'. 1071 003‘].
Complete Foliage Root
mam Sr mam Sr
Applied High 0a 3.66 7.58
to roots Low Ga 5.08 10.85
BEET Applied to High Ga 8.15 0.11
complete Low Ca 10.72 0.36
foliage
Control High Ga 0.61 0.38
Low Ga 0.76 0.00

 

 

 

 

"Eft'p
". e s

..
II! A .
tht .

.

'A‘u“ n.

~-o--A...

E

' - .
"- ...,..
.

"‘5 V...~‘

ENE
..,_

61..

I.“’
iv

a.“

o
.352

(I‘

37

Experiment 2

Object1ve

To study the growth and mineral composition of tomato
and beet plants when grown for prolonged periods in nutrient
solutions containing various amounts of calcium, strontium

and combinations of calcium.and strontium.

Materials and methods

Plants were grown in twelve different nutrient solutions
(Table V). Full Hoagland's solution was used for all treat-
ments except that calcium was reduced, combined with stron-
tium, or substituted by strontium in the various treatments.
When the sum.of calcium nitrate and strontium.nitrate was
less than eight milliequivalents per liter, ammonium nitrate
was added to make up the lost nitrogen. The treatment desig-
nations shown in Table V refer to the equivalent percentage
of the element in relation to full Hoagland's solution cal-
ciwm (160 ppm). These designations will be used in the
tables, figures, and discussion which follow.

Tomato seeds were planted in vermiculite on September 23,
1952. Seedlings were transplanted to Wausau Quartz #8 in
nix-inch clay pots on October 29. Treatments were started two
days later. harvests of five plants each.were made after 30
and hbvdays of growth in the various nutrient solutions. Beets

"BTW! seeded in vermiculite on November 23, 1952, and transplanted

.- A . ~ A ‘ .4 . A . u. I IV e u \R...‘ pfi FL hlu< BLIH.<2;U.— Cc. .UI- - In.
. . . N w EHY ~I1~ 2< N.~ .u.
- .I -A\~.h|. I. 0- '.EV ~AV-.~ 1". .. \

wry” l n 2.
a“ H. ah. RBI-I1 .. l... P. . . . .
. _
H... ,
.

a ... a £4.

38

. .eBsopfinHoE one nommoo .oswu .omeaewsua
.soaop 50.3 33.33 .gwmocmse .mseonmmofi .gawmapom mo mvgoau Hoswo nebdoooa evanescence» HQ e

 

 

08 3A 2. o o o o .5 o + 8 o «a
S“ 83 8 u o 8 o .6 on G
o8 8” «e e o e: o .8 8, on
08 N2 8 e o «8 o .8 E. a
3m 83 3 o o S» o .8 o3 a
3». e3 3 e N «3 ca .8 2. + 8 an a.
3» e3 3 e e e: on em 3 + 8 on o
as 82 3 a. o 8 02 em on + 8 2. 8
SN «3 8 o a o 3 8 3 e
03 8a «a. o e o 8 8 8 n
as «2 on o m 0 on." 8 2. a
as 2: 3 o o o 03 8 8n n
58888 538
duos 33»: 52°32 .8»: a...“ 53:83 6538 83:3.3 . has:
25.: 8mg»: unflipsufifii 833a eon 3.3m . 885.89

 

I..-’

ewnogm 302% mg 593 my; gun 95 2.4.39 On. Enema—Hm mange 35ng 955.82

b man.

' '""QIi
T '."‘,'t 'k' 3....“ ‘2. \.

 

 

 

 

‘ . '

... “F

t J

..».a...
.

.3, 0,.

...¢ ...
t“. 5‘
h.“ ..'

v
‘A TV
‘” he

"F .0
A: V;

1IOL
\" 'k

5a.,

(1‘

39

to new wausau Quartz #8 on January 8, 1953, at which time
treatments were initiated. Five plants were harvested at
each of the harvest period, u6, 68, and 90 days after the
beginning of treatment. Twelve large pans 50 by 27 inches
and four inches deep were used so that the plants for each
treatment were continually subjected to the same solution.
The nutrient solutions were changed weekly to prevent build-
up of salt concentration and algae population.

Yield data collected included height measurements of
both tomato and beet, root diameters of beets, fresh weight,
and dry weight. The plant tissues were analyzed for potas-
sium, strontium.and calcium.using the flame spectrophotometer
and for the elements magnesiwm, phosphorus, iron, manganese,
copper, and boron.using the spectrograph.

The statistical treatment consisted of calculating the
standard deviation from.the mean of the five values for any
particular measurement. In the following discussion any
treatment mean which fell outside two standard deviations
from.the mean of the 100 Ca treatment was considered signifi-
cantly different from.the 100 Ca treatment. Numerical values
of the 100 Ca mean plus and minus two standard deviations (s)
are given in all tables._ In all cases the 100 Ca treatment
was used as the basis for comparison. There were some dif-
ferences between means however, which appear real even though
the difference is not as large as two standard deviations.

This resulted from.high variability in the measurements of

no

the five 100 Ca samples. The differences among plants
treated alike is an indication of natural plant variability
and genetic heterogeneity. The analysis of variance was
not used because the method of growing plants did not meet

the random distribution requirement.

Results

A. Observations. Tomato plants showed no visible
effect of the treatments for the first fifteen days. By
the twentieth day plants receiving the 100 Sr treatment were
showing a lag in growth. At 22 days strontium toxicity
symptoms began to appear on the leaves, and by 28 days these
symptoms were well developed and began to appear in the 75
Sr and 25 Ca + 75 Sr treatments. However the latter had
much less injury than either 75 Sr or 100 Sr. The pattern
of leaf necrosis was interesting. The newly formed leaves
appeared normal until they became two to three inches long.
Of the four or five fully expanded leaves the younger ones
showed a marked necrosis of the tips of the leaflets while
on older leaves the necrosis appeared at the base of the
leaflets with the tip remaining green. At the 30 day harvest,
the roots of all plants appeared.normal except that roots
of plants receiving the 100 Sr treatment were somewhat
smaller.

Strontium toxicity continued to increase until the

final harvest at u6 days. By this time most leaves of plants

81

receiving the 100 Sr treatment were completely dead but
new leaves continued to form at the apex. A few leaves
were also dead on plants grown at 75 Sr. Strontium
toxicity was evident on plants in the 50 Sr and 25 Sr
treatments but it decreased sharply with the amount of
strontium in the nutrient solution. Injury was present
on plants in the 25 Ca + 75 Sr treatment but was less se-
vere than with those grown at 75 Sr without calcium. There
was no evidence of calcium deficiency or strontium.toxicity
in other treatments. The plants in the 0 Ca + 0 Sr treat-
ments were as vigorous and healthy as those in treatments
receiving calcium. These plants were apparently obtaining
sufficient calcium to support growth.from impurities in the
distilled water or nutrient salts. Tomato roots did not
show any of the usual symptoms of calcium.deficiency in any
treatment. Only the roots of plants in the 100 Sr and 75
Sr treatments were appreciably smaller than those in the
100 Ca treatment. Two of the treatments, 25 Ca and 0 Ca +
0 Sr, appeared to have larger root systems than the 100 Ca
treatment. There was one marked difference between high
calcium and low or no calcium roots. The fresh tomato roots
in the 25 Ca, 50 Ca + 50 Sr, 25 Ca + 75 Sr, 100 Sr, 75 Sr,
50 Sr, 25 Sr, and 0 Ca + 0 Sr treatments were much more
brittle than the roots of the other four treatments.
Initial growth of beet plants was very slow through

the month of January because of short days and low light

MI TIL-slit... $58.15.. .
t . . 1 .

._
l
..

mx

  

intensity. After thirty days of treatment the plants in
the 100 Sr treatment were noticeably smaller than those

in all other treatments, and dark red patches began to
develop on the leaf blades. This redness of the leaves

was also present to a lesser extent on plants in the 75 Sr
and 25 Ca + 75 Sr treatments at the time of the first har-
vest. By the second harvest at 68 days the reddening of
younger leaves had become more general on plants in the 100
Sr, 75 Sr and 25 Ca + 75 Sr treatments and was also evident
on plants receiving the 50 Sr and 25 Sr treatments. This
symptom.was much less pronounced on plants in.the 25 Ca +
75 Sr treatment than on those in the 75 Sr treatment (see
Figure 7). Plants in 100 Sr and 75 Sr treatments were con-
siderably smaller than those in all other treatments. These
conditions persisted until the final harvest at 90 days.
Shortly after the second harvest the 25 Ga plants nearly
stopped growing so at the third harvest these plants were
considerably smaller than the 100 Ca plants.

The pictures shown in Figures 3 to 8 were taken two
days before the third and final beet harvest. They show
the differences between treatments and particularly the
poor growth of plants in the 25 Ca, 100 Sr and 75 Sr nu-
trient solutions. The dark red color produced by leaves of
plants in strontium treatments is probably a symptom of

strontium toxicity rather than calcium deficiency because

Fig. 3. Beat plants grown for 88 days in
nutrient solutions with decreasing
calcium content and no strontium.

 

Fig. a. Boat plants grown for 88 days in
nutrient solutions with decreasing
strontium.content and.no calcium.

 

 

.4 i
F

. . . ~ '. 1', ' 7 .
‘ '1. 6‘ A}! 5584...? Jim-1‘34

Fig. 5,

Fig. 6.

Beet plants grown for 88 days in nutrient
solutions containing the highest levels
of ca1cium.(1eft) and strontium (right)
andrwith various combinations of the two
elements (center).

Beet plants grown for 88 days at the
highest levels of calcium (left) and
strontium (center) compared with a
plant grown in nutrient solution with

- no calcium or strontium.added (right).

Figure 6

 

 

Fig. 7.

Fig. 8.

Beet plants grown for 88 days in the
nutrient solutions indicated. note
the greater strontium toxicity when
calcium is absent from the nutrient
solution.

Beet plants grown for 88 days in the
indicated nutrient solutions showing
better growth by a low level of
strontium.than a low level of calcrmm.

1+5

 

Figure 7

 

Figure 8

us

both apical and root growing points were not affected and
the 0 Ca + 0 Sr treatment did not have the symptom. Figures
5 and 7 show that the addition of calcium to the nutrient
solution suppressed the leaf color change. Many of the red
leaves did not develop full size and were more rigid and
erect that normal leaves. ‘The beet roots showed no toxicity
or deficiency symptoms. The fleshy roots all appeared nor-
mal even though there was considerable difference in size.
Fibrous roots in the various treatments were all about the
same except in the 25 Ca treatment where they were much

darker in color.

B, Growth measurements. Several plant measurements
were taken at the various harvest times. These are shown
in Table VI. Tomato plants were significantly shorter in
the high strontium treatments at both.harvests. Beet plant
heights and root diameters were also less at the high stron-
tium.levels but the differences were not as pronounced as
with the tomato. ' The. small size offbeat plants in the 25
Ca treatment at 90 days is also evident in Table VI. Beets
‘were apparently more tolerant of strontium than tomato
plants because there was no necrosis of beet leaves.

The dry weights are shown in Table VII for tomato plants
andvTable VIII for beet plants. These values are presented
graphically in Figures 9 and 10. Total plant dry weights

at the final harvests are also shown in Figures 15 and 16.

#7

.m o.:~ o.~m p.8o m.:m n m- use: co co“
m o.om m.:n o.ooa ~.os a m. use: no ooa

 

 

m.m .om 0.0m :.mm ~.~m so 0 + so 0
H.m .em ~.om :.oe :.mm so mm

m.s o.am o.mm :.:e m.sm so om

m.: m.:m o.am :.H o.om so mu

m.: o.om ~.om 0.5 o.o~ so ooa

o.e o.om o.am «.05 o.am so me + no mm
o.m o.~m o.mm m.oo «.mm on om + «o om
o.m :.mm o.em .sm o.:m no mm + no me
0.: 4mm mom is mean 8 mm
o.: m.om :.am o.oo m.am so om
~.m m.mm .om o.oo o.H: no me
:.m N.mm .om o.oo. o.os so ooa

when 00 when om when we when 0: when on
A.sov soooseao onmwmm.ca meoomeaocoo onmaom mwnmmwooesocoo
poem 098509 codpdaom

 

Anpcsam w no neexm
mzHa mo mmawzmq mDOHm<> mom 230mm maoom ammm mo mmmemz<HQ Q24
mazmqm ammm Dam cadzoa mo mamuHmm zo mZOHaqum szmHmBDz ZDHBzomemIZDHuamo mo muzmbumzH mma

H> mumda

 

 

mm.o om.o mm.m mm.H mH.o oe.H u m- cams «o ooH

Ho.mH mm.H .sH so. : ms.o os.m a m+ zoos so ooH

os.o :H.H om.o om.m Hm.o eo.H an o + so 0

on.» oe.o mo.» Ho.~ m~.o Ne.H no mm

ea.o No.0 co.» e~.~ om.o o.H an om

:e.o 00.0 mo.o ~3.H o~.o e~.H so me

ms.w em.o Hm.~ ms.H eH.o o~.H so ooH

ee.o so.o oo.s oe.H mm. o mo. H no me + no mm

No.0H No.0 om.o -.m om. o 38. H so on + so on

ma.0H mo.H no.8 HH.~ em. 0 mo.H mm mm + no me

oo.o um.H o». e o~.~ os.o mo. H no mm

mm.HH oH.H on.oH mH.~ :w. c He. H so om

ee.o oo. an. o oo.~ mm. o oe.~ do me

NH.HH eo.o o~.oH o». o~.o os.~ no ooH

sssHm a onaHm 8

Hence soon on Hence ooom as so no
mummlmm mummnmn » use he

 

 

38s.; .Hea madam;
exam o: one on.aea arose nausea ceases so

.525”? Nmm "BE. 20 mZOHBDAom 82$ng ZDHBZDMHWIZDHS<O ho monDJMZH Ema

HH> 392..

1+ .

 

 

me; was as 0H.H 00.0 0N.H 3.0 8.0 8.0 m m- 5% 8 00H
3.0» 3.3 8.2 No.3 No.0 3:. «To 8.0 88 a N. 5% 8 00H
8.2 2.: 85. no.» .8.» 3.0 H«.H 3.0 «1H .5. 0 + 8 0
5.: »o.o 3:. 0H.» «0.» 0»... H».H 3.0 $4 a» 3
8.3 005 3.6 00.0 8.“ 3.» ~».H 8.0 8A a» a»
00.2 «as. 3.» as.» H...» »H.» 3; 2.0. aH.H so 2.
3.3 mm.» 3.0 2..» 8H 00.» «0H 8.0 3.0 s» 00H
8.3 »».m a»; 8.2. H0.» H»... o»; 5.0 HTH a» 2. + 8 3
8.3 00.2 8.2 3.0 88 3.0 »m.H »».0 0m; a» 0» + 8 0»
8.0” H».»H 8.2 8.2. 00." 8.0 SH 36 «NH .5 on + 8 2.
2.2 03? »».» 3.0 2.8 00:. $.H H».0 »H.H 8 on
5.2 3.2 3.4. 2..» on.“ 3;. »H.H 3.0 «0.0 8 0»
84... 8.2 5.0 3.2. 8.» 03. »».H 3.0 8H 8 2.
2.8. 2.2 8.» 3:. 8.» 8.. EH 3.0 0».H 8 00H
v85 988 efiHm
H32. seem so.» H38. 08m son. :52. 08m 00». £6388

use 00 93. o» are 00

 

 

Apnea.— aen aging

.wba 00 GE .8 00¢ me E80 my: “Mum

HHHD

mama;

ho gnaw: Mun mm: .mc ugh—56m gasp: thgggg ho Bahama mm."

50

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Ffi
----Wor
F T ouAT o umnuuu “001’
4°.O — TmrAANT DAYS
I'- Z0.0
I
(D
‘ Io.oJ __ 43
I.“ j if I N “V” ““ d ~~ I"‘6
3 1‘ ’I W
F \
8. ‘
).
m
D
(D I.
2 "PM ’ . V
< . a. a
c .. at
(9 i , 0 ‘ ‘s 5‘-
§M"'z. 5,: J... .30
‘* “ * ' .0»... ~ ~.. .0“
_ W fi- MK. 3°“, n...
, _.. 7- 4 , ,4 3". ‘
0.: , ,

 

 

 

 

1m COCA COCA OOA
IOOOA 7.“ IO“ I.“ '... IOOR TOUR IOOOR TIOR ”OR 888R OCR

EQUIVALENT PROPORTION OF CALCIUM (CAI AND

STRONTIUN ("I IN THE NUTRIENT SOLUTIONS

F15. 9. The influence of calcium-strontium
nutrient solutions on the dry weight of
tomato plants treated for 30 and h6 days.
(Mean of five plants.)

 

 

51

 

 

D R Y’ \N EII G H T

G R A ll S

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

B E E T Illlllllllll ROOT ' " "'
Iv
2 o c ‘\‘ / \-\ so
"In § ’0
lo n "mun”. 5:] ‘x ""9 _ “m 90
0V — - ~ 09% ill I '9 - ' ”II,“
‘~ ’0 e ‘0 7 ‘
fi# *1? ‘5 . ‘ -r O
‘\ I "a “,9“ I
\ i ,
5 G v 74",.‘A \ 1
. -0. A '\ , ’p’ 83
‘
‘ ‘ up" , \ , , , , .. fi”
\ ,d . “ SS
"nun". , I . ,3 ——4P’ , , 3 i a“:
nun", "n" “mine-III. w . .......
..... ... ‘ . ‘ .n I ““‘|I , '
‘0, “up
“a ““8, .. ,0 0 ,
’_ — ~ ‘ 4 k A A
~‘ \/ v" \ /~ A.
| A ‘ A," a 1’ ‘~ "
.v ‘K V I
‘ V \‘ I , 7 A n A.
0.5
‘0: "I In..." _.n‘|""o ‘ i
"'00,. .. ‘01P"“I l '5'", ¢ ”h". .‘I‘fl‘u Jfiunu 48
' "I, 9““ "‘0 “O.
A fi’e
0.I

 

 

 

 

 

 

 

 

 

TSCA SOOA IICA OOA
IOOCA TSOA SOOA COCA 35.. '0'. 7”. IOOSR TOUR SOUR IIIR OSR

EQUIVALENT PROPORTION OF CALCIUM (CAI AND
STRONTIUN (Ill) IN THE NUTRIENT SOLUTIONS

 

Fig. 10. The influence of calcium—strontium

nutrient solutions on the dry weight of beet

plants treated for us, 68 and 90 days. (Mean
of five plants.)

 

‘ n

Figures 9 and 10 show that top growth and root growth are
about equally affected by treatments depressing total
growth. Plant growth was least in the 100 Sr treatment
by both crops at all harvests. Smaller amounts of strontium
in the nutrient solution had much less effect on growth.
Where calcium.and strontium were present together, growth
was better than with the same amount of strontium alone,
and for beet plants, it was also better than the same amount
of calcium.alone. Figure 10 shows that the poor growth of
25 Ca plants did not appear until the 90 day harvest. The
normal growth of plants in the 0 Ca + 0 Sr treatment was
unexpected but nevertheless apparent at all harvests.
Average Top/Root ratios on a dry weight basis are shown
in Table IX. The 25 Ga and 0 Ca + 0 Sr treatments caused
a significantly lower tomato plant T/R ratio than any others,
due primarily to greater root production. The treatments
had no significant effect on the T/R ratio of beets.
Treatments also had little or no effect on the percent dry

weight of tomato or best tissues as shown in Table X. The
high.percent dry weight of twmato tops grown in 25 Ca + 75 Sr,
100 Sr, and 75 Sr treatments was caused by some leaf tissue
being dead and dry at the time fresh.weights were taken.

c. Chemical Analysis. Spectrographic analysis of

the samples harvested from.tomato plants grown for M6 days

TABLE IX

53

DRY WEIGHI' TOP/ROOT RATIOS OF TOMATO AND BEEI‘ MTS GWEN FOR

vmous LHGTHS OF TIME IN NUTRIbN‘l‘ SOLUTIONS (UNTAINING
mums” ADMITS OF CALCIUM AND STROHTIUII.

(Values given are the mean of five plants)

 

 

 

 

Treatment Tomato Beet

30 days 46 dqa 46 days 68 days 90 days
100 Ga 8.71 10.49 3.27 1.43 .686
75 Ga 8.73 9.85 3.37 1.45 .804
50 Ca 8.11 9.10 8.90 1.58 .721
25 C. 4.73 6.35 3064 1049 .733
75 c. + 25 Sr 7.11 9.25 3.54 1.72 .970
so c. +50 Sr 6.83 10.56 3.72 1.97 .720
25 C. +75 81' 6065 9047 304° 1064 .808
100 Sr 7059 10071 3073 1065 e745
75 Sr 6057 906° 3.80 1036 0813
60 81' 6.71 9010 304‘ 1040 0804
25 Sr 70% 9.49 3048 1.54 0780
0 Ca + 0 Sr 6043 7.43 5.91 1043 0743
100 Ca New +2 8 9.83 11071 4053 1e99 0880
100 Ca mew -2 3 7059 9027 2001 0087 04:92

Sb.

 

 

02HM2 00mm 00H02 00.0 00.0 00.0 00.0 00.0 0 0._0000200 002
00 -2 20 c2 00 22 00.22 00.02 00.02 00.0 00.0 0 0+ 0000 00 002
00.22 00.02 02.22 00.0 00.02 00.0 20.0 00.0 00 0 .+ 00 0
20.22 00.02 02002. 00.0 00.0 00.0 00.0 00.0 00 00
00.02 00.02 00.22 20.02 00.0 00.0 00.0 00.0 00 00
00.02 00.02 00.02 20.0 20.0 20.0 00.0 02.0 00 00
20.02 00.02 00.22 00.0 20.02 00.0 00.02 02.0 00 002
20.02 02.02 00.02 00.0 00.02 00.0 00.» 00.0 00 00_+ .0 00
00.02 00.02 00.22 00.0 00.0 00.0 00.0 00.0 00 00 +_00 00
20.02 00.02 00.02 00.0 00.0 00.0 00.0 00.0 00 00 +..0 00
00.02 00.22 00.02 00.02 00.0 00.0 00.0 00.0 00 00
00.22 00.02 02.02 00.02 00.0 00.0 02.0 02.0 00 0»
00.02 00.02 00.22 00.02 00.22 00.02. 02.0 00.0 .0 00
00.02 00.22 00.02 00.0 00.22 00.0 00.0 02.0 .0 002
poom no.2. room men. room nos no.2. 22.0.2.
0000 00 00.0 00 .000 00 0000 00 0000 0»
poem ovsaoa , #28222th

 

 

7322:.» aka «o ales on» 93 Gram 00222.35
42425.03 ml: .250“:th 2 Egg 2:24 muons—Sam. Humbug:
33.2.2351:ng 9552402 an 0295 2.24.202 Sum 52 23292. no “HEB: En sumo“:

K may

SS

in the various culture solutions are shown in Table XI.
Table XII contains the same data for the 90 day beet
plant samples. Tops and roots were analyzed for the ele-
ments magnesium, boron, phosphorus, iron, manganese and
copper. Tables XIII and XIV show the top and root content
of potassiwm, calcium and strontimm in tomatoes and beets
at all harvests. These values were determined by use of
the flame spectrophotometer. The plant composition of
all nine elements at the time of final harvest are shown
in Figures ll, 12, 13, and In for tomato tops, tomato
roots, beet tops and beet roots respectively.

These tables and figures show that the nutrient solu-
tion variables, calcium and strontium, vary in the plant
tissue in proportion to the amount in the nutrient solu-
tion. The only exception was the strontium content of
beet roots where both 50 Sr and 75 Sr treated roots con-
tained more strontium than those in the 100 Sr treatment.
All plants contained some calcium.even where none was
added to the nutrient solution. The different nutrient
treatments had little effect on the content of potassium
and copper in any of the four plant tissues.

The effect of treatment on plant tissue content of
the other five elements can be summarized as follows. The
mineral concentration in tissues from plants grown in the

100 Ca nutrient solution was used as the standard for

comparison.

.50

 

 

I. .0200. I. 00.00. I. 0000. E. 000. I 20000. I mmm. 0 m: 20002.2 so 00."
I 0000. I 00000. I memo. I 000.. I. once. 1.. ems. 0 0+ 2200.22 so 82
0.000. 00000. 022.0. 2.300. 02.8. 3.8. 032.2 000.2 0000. 300. 0.8. “«2.. .5 o + do 0
0000. 0000. 002.0. 2220. 0000. 0000. 000. 000.2 0000. 008. 000. 020. .20 00
0000. 0000. 2.3. .35. 3:. 003. «No.2 on». 9.60. 850. one. 203.. am On
I 0000. I 00.8. I was. 1.. $0. I 030. I no». .20 m0.
I 0000. I n80. I 2.68. I cum. II 28. I «so. .20 00."
2.00. 0000. 800. 5.00. 002.6. coco. and.“ can. Soc. 300. Ono. 0.8. no 9. + Co on
0.000. 0000. 33. $00. 3.00. @000. wood“ «3.. once. «woo. woo. pom. am on .2. eo on
0900. $00. owno. Coo. «Ono. 58. new. 031 hvuoc. 3.00. n9. mom. no on .2. so 2.
00.2.6. 0000. name. 300. 300. 33. ”no. nae. «moo. 3.8. 30. «.3. so no
$00. 0000. :3. «000. 003. $8. $12 Gm. 008. 20.30. «on. on... 20o 00
000.9. 0.000. 0000. $00. .300. 85. 03.." wow. «moo. ”#00. «me. one. so or
0000. 208. 0.00.0. 300. 030. .820. moo. So. 800. 0250. who. 000. ‘0 8a
poem no.2. poom no.2. poem men voom non. aoom no.2. poem no.2.
.0258 0020qu: 220.; 022.202.2202..“ 25.209 252.0253. visa-e29

 

72230.0 PG 023 no 9289222 ed 200.200.2228 flour-29280228

mud: we mom agar map—«Hm 050.2. ho H5928 g;
mmh. 20 mange BEES: Eazaaménog

HK H.349

magi; to No BREE amp

.0 «a»? 2! o usaeumoueoemmv

57

 

 

2200. 0200. 0000. 0000. 0000. 0000. 000. 000. 0000. 2.000. 020. 200. 0 0... 28002 00 002
0000. 2000. 0000. 0.020. 0.000. 0020. 2.2.22. 0.20. 02.00. 0020. 30. 220. 0 0+ 2802 0o 002
2000. 0000. 0000. 0020. 20.00. 2.20. 000. 002.2 0000. 0020. 200. 000. .20 0 + 0o 0
2000. 2000. 0000. 2200. 0020. 0020. 00¢. 000. 2000. 0000. 220. 000. .20 00
0000. 0000. 0000. 0000. 2020. «020. 20¢. 000. 0000. 0000. 000. 000. .20 00
0000. 0000. 2020. 0020. 0000. 0000. 200. 000. 0000. 2000. 00¢. 000. .20 00.
0000. 0000. 0000. “520. 0020. 0.000. 020. 00.0. 2000. «000. 000. 000. .20 002
2000. 0000. 0000. 0020. 0000. 00.00. 000. 000. 0000. #000. 00¢. 000. .20 00. + no 00
0000. 0000. 0000. 0220. 0000. 820. 020. 000. 2000. 02.00. 000. 000. .20 00 + do 00
0000. 0000. 0000. 2020. .0000. 0220. 000. 000. 0200. 0000. 000. 200. .20 00 +8 00
0000. 0000. 2000. 0220. 0000. 820. 200. 000. 0000. 0000. 000. 200. do 00
2000. 0000. 22.00. 0020. 0000. 0000. 200. 200. 0200. 00.00. 000. 000.. do 00
0000. 0000. 0000. 0020. 0200. 0000. 03. 000. 0200. 0v00. 000. 020.. do 00.
:00. 0000. 02.00. 0220. 0020. 2000. 000. 000. 2000. 0000. 200. 000. do 002
9000 00.0 9000 220.2. 0.000 no.2. 0000 no.2 0000 no“. 9032 00.2.
.6008 000220028: 28.22 022002200082 220.200 5.202290: 983900.20.

 

 

2.20203 0.22. on» .20 089022 0. 0030.298 22029000302200

.020 022022- 02300000030000

0:9 00 ~29— aama 0.2.592 Hum .00 95.2.38 2552—:
may 8 0222.25.28 Sm EEK 33929290422220.2020 0502224; 020 NOEQEZH Mm“.

HHN “2.54.2.

58

TABLE XIII

THE INFLUBICE OF VARIOUS CALCIUM-S‘I‘HONTIUM NUTRII'NT SOLUI'IONS ON THE POTASSIUM,
CALCIUM 1ND STRWTIUM (INTENT OF TOMATO PLANTS TREATED FDR 30 AND 46 DAYS

(Home photometric analysis. Gonomtretion expressed
as percent of the dry weight.)

 

 

 

Treatnmt Growth Pot as 61 um Cal 01 an Stronti an
Period Top Root Top Root Top Root
100 0. 50 days 6.48 7.07 1.34 0.37 0.02 0.01
46 a“. 7019 6016 1043 0049 0001 0002
46 days 7.50 6.51 1.01 0.16 0.02 0.01
50 CC 30 0”. 8.65 6091 0071 0014 0002 0001
46 days 7.66 6.26 0.65 0.15 0.01 0.02
46 dqfl 6093 5.66 0051 00m 0002 0002
75 Cu + 25 Sr 30 d”! 6.09 6.69 1.27 0.43 0.56 0.24
46 days 7.14 5.65 1.26 0.40 0.63 0.42
50 Us + 50 Sr 30 days 7.69 6.56 1.07 0.33 1.00 0.56
46 days 7.38 5087 0094 0029 1014 0072
25 C. + 75 s:- 50 days 6.01 6.30 0.79 0.22 1.46 0.76
46 days 6.76 5.50 0.66 0.16 1.65 0.78
100 Sr 30 dws 7.16 6.63 0.61 0.15 2.36 1.07
46 days 7001 6036 0041 0010 2034 1002
75 Sr 30 days 7078 6056 0044 0007 1032 0094
46 dvl 7021 5023 0027 0004 1051 0.70
50 61‘ 30 days 6.02 6.32 0.34 0.05 0.66 0.46
46 0W6 7065 5045 0024 000‘ 0.91 0064
25 s:- 50 day. 7.79 6.15 0.24 0.05 0.46 0.25
46 dWB 7034 507‘ 0018 0004 0047 0046
0
c. + 0 SI. 30 d”! 7084 601‘ 0.14 0004 0001 0002
1 46 dw. 7005 6014 0.11 0.03 0.00 0001
1W3 43 days 8W -- 11.49 -- A 0.02 --
earl -2 s 46 days 6.61 -- 1.37 -- 0.00 --

‘l

59

TABLE XIV

THE INFLUI'N CE OF VARIOUS CALCIUM-STRONTIUM NUTRIBWT SOLUTIONS OF! THE POTAbSIUM
CALCIUM AND STRWTIUM (INT MIT 01" BEEP PLANTS TREATED FOR 46, 68 AND 90 DAYS

(Flame Photometric analysis. Concentration expressed as percent of the dry weight)

—_

‘—

 

 

Treetment Growth Pot as aium 01 01 um Strontium
Period Top Root Top Root Top Root
100 0. 46 days 6.59 4.90 1.51 0.25 0.06 0.02
66 days 6.26 3.94 1.96 0.20 0.06 0.01
90 day. 9.07 5.99 1.65 0.19 0.02 0.02
68 d”. 7071 3092 1052 0014 0007 0001
90 days 8035 3094 1064 0014 0.02 0001
50 c. 46 dq. 7.60 5.12 1.06 0.20 0.16 0.06
66 days 7.39 5.90 1.14 0.10 0.10 0.02
90 a”. 8002 4003 1022 0009 0003 0001
25 46 days 7034 4052 0080 0.06 00% 0002
68 day. 6.92 4.02 0.76 0.04 0.07 0.01
90 d“. 6093 5037 0080 0005 0007 0002
75 CG + 25 Sr 46 daye 6.16 5.09 1.40 0.23 0.60 0.13
66 days 7.69 4.04 1.70 0.16 0.76 0.14
90 CW. 8010 3058 1070 0013 0075 00 23
50 C. ‘l’ 50 Sr 46 days 6.47 3.42 1.10 0.21 1.24 0.41
68 deyo 7.74 3.71 1.18 0.14 1.52 0.30
90 a”. 8048 3087 1000 0007 1068 0040
66 days 7.76 4.16 0.96 0.10 2.59 0.49
90 days 8078 3087 0091 0007 2037 00“
100 Sr 46 dva 7099 6001 0049 0.06 2014 0069
68 day! 8042 3088 0048 0005 2094 0059
90 days 9.15 4.05 0.46 0.04 2.99 0.36
75 Sr 46 day. 7.62 4.66 0.56 0.09 1.69 0.66
68 d”! 8001 3054 0048 0006 1083 0053
90 dIyl 8078 3074 0039 0004 200‘ 0058
60 Sr 46 dws 7.38 4.62 0.50 0.m 0.92 0.68
66 days 7.76 5.72 0.52 0.04 1.16 0.63
90 d”. 8014 8065 0044 0004 1018 0076
25 SP 46 a”. 7000 0050 004‘ 0007 0051 0032
68 dWB 8026 0022 00$ 000‘ 0008 0038
0 90 days 6.34 4.05 0.36 0.02 0.53 0.33
0., 0 Sr 46 0”! 8011 4085 0025 0004 0.06 0004
66 «y. 8.11 5.66 0.26 0.02 0.01 0.01
90 city: 7090 3037 00 27 0002 0003 0.00
\
c. Mean + 7
Me 2 s 90 days 10.61 5.99 2.29 0.26 0.05 0.03
‘2 s 90 days 7.33 1.99 1.37 0.10 0.00 0.00

60

  

uncut)

   

........

DRY

   

........

   

I PERCENT OF THE

COMPOSITION

  
       

MINERAL

........

 
  

   

OOA

IOOIR 736R 606R IGOR OOR

 

160A
IOOOA 730A 600A COCA IOIR '0'. 7”“

     

EQUIVALENT PROPORTION OF CALOIUN (CAI AND
STRONTIUN (0:) IN THE NUTRIENT SOLUTIONS

        
 

 

Fig. 11. The influence of various calcium-
strontium nutrient solutions on the mineral
content of tomato tops treated for I16 days.

61

      
         
    
   
        

THE DRY. WEIGHT)

OF

(PERCENT

........

CONPOSITION

MINERAL

      

   

”c“ :50. noon 760a 500a use °°‘

”c‘ "c“ an sou run on

   
  

IOOCA TOCA

  

           
     

EQUIVALENT PROPORTION OF CALCIUM (CAI AND
STRONTIUM (an) IN THE NUTRIENT SOLUTIONS

 

Fig. 12. The influence of various calcium-
strontium nutrient solutions on the mineral
content of tomato roots treated for I16 days.

62

......

  

....................

 
 
 

DRY

THE

   

(PERCENT OF

   

MINERAL COMFOQITION

   

 
 

I

       

OCA
IOOCA TOCA COCA COCA IIIR '0‘. 1.” IOOSR 766R 906R EIOR OCR

           
 

EQUIVALENT PROPORTION OF CALCIUM (CAI AND
STRONTIUM (OR) IN THE NUTRIENT SOLUTIONS

        

Fig. 13. The influence of various calcium-
strontium nutrient solutions on the mineral
content of beet tops treated for 90 days.

63

’1! ‘1‘:

 
     

WEIGHT)

DRY

 
   
  

OF

(PERCENT

   

   

COMPOSITION

MINERAL

    

..,.

  

OCA
IOOOR TOSR 306R 838R OCR

 
   
 

IOOCA TOCA COCA COCA

  

use son "on
PROPORTION OF CALCIUM (CAI AND
(SI) IN THE NUTRIENT SOLUTIONS

      

                 

EQUIVALENT
STRONTIUM

 

   

 

       

Fig. 1h. The influence of various calcium-
strontium nutrient solutions on the mineral
content of beet roots treated for 90 days.

61+

Thxmito tops: The iron concentration varied somewhat but

variation was not correlated with treatment. Boron
was significantly higher in the 25 Sr and 0 Ca + 0 Sr
treatments but was otherwise relatively constant. All
the 0 Ca treatments except 100 Sr and 75 Sr showed a
significant increase in phosphorus, magnesium and

manganese concentration.

Tomato roots: Variation in nutrient solutions had little

Beet

Beet

effect on magnesium.and boron concentration. Phosphorus
and manganese were also fairly constant except that

0 Ca + 0 Sr showed a considerably higher phosphorus
concentration and 25 Ca roots had low manganese. Iron
was much higher when calcium.was absent from the nutrient
solution.

tops: A lack of calcium in the nutrient solution.
caused some increase in boron, and a significant in-
crease in phosphorus and manganese. Iron was appreciably
higher in the 50 Sr, 25 Sr, and 0 Ca + 0 Sr treatments.
The addition of strontimm to the nutrient solution,
regardless of caloium.content, caused a significant
increase in.magnesium.content.

roots: The treatments had no significant effect on
boron and iron content. Lack of calcium.in the nutrient

solution caused an increase in manganese content; high

65

strontium caused an increase in magnesium; while either

a lack of calcium or high strontium caused an increase

in phosphorus content.

These results show that in many cases strontium can be
added or substituted for the nutrient solution calcium and
not cause any pronounced effect upon the absorption and ac-
cumulation of other plant nutrients. 0n the other hand the
tissue accumulation of some elements is considerably affected
by the addition of strontium or the withholding of calcium.

The plants in this experiment were found to contain gen-
erally higher concentrations of several elements than those
given by Beeson (2) and Goodall and Gregory (16) for tomatoes
and beets. however, the analyses for calcium, potassium,
maSinesium and phosphorus agree well with those of Newton (39)
who grew plants in nutrient solutions very similar to the 100
Ca treatment here. He noted that plants grown in sand or
solution culture are often higher in mineral constituents,
PPObably because nutrient solutions are more concentrated
tShari normal soil solutions.

It is interesting to compare the mineral content'of
Plant tops with that of the roots. Tomato tops contain more
Potassium, calcium, magnesium and boron, while the roots are
higher in phosphorus, iron, manganese and copper. Beet tops
°°ntain more potassium, calcium, magnesium, boron and mangan-

°3°. while the roots are higher in iron and copper. It should

66

be recognized that some and perhaps much of the mineral con-

centration r0corded for roots represents adsorbed rather than

absorbed nutrients. Phosphorus is about the same in beet

tops and roots. Both tomato and beet plants accumulate a

higher concentration of strontium in the tops than in the

roots when grown for prolonged periods in strontium solu-

tions. Where analyses were made at all times of harvest

(Tables XIII and XIV) it was found that the potassium content
of beet tops tends to increase with age while in beet roots,
tomato tops and tomato roots the tendency is for a decrease.

A comparison of calcium and strontium absorption on a

Percent dry weight basis is not strictly valid because of

the higher atomic weight of strontium. Therefore the plant

content of these two elements was converted to milliequiva-

lents per gram of dry tissue. These values are shown in

Table XV for tomato and Table XVI for best. They are also
Shown in Figures 15 and 16 where a comparison is made with

the total plant dry weight at the last harvest. On a milli-

equivalents basis tomato tops and best tops can accumulate

nearly as much strontium as calcium. Tomato and beat roots

8oppear to take up as much or more strontium than calcium but
Part of the strontium determined in root samples may be ad-

sorbed on the roots rather than absorbed into them. It should
also be noted that the addition of strontium to the 75, 50
and 25 calcium levels generally caused an increased accumu-

lation of calcium in all four tissues, although the increase

TABL E XV

6?

CALCIUM AND STmNTIUM (DNTE‘IT OF TOMATO PLANTS EXPRESSED A5
MILLIEQUIVALEITS PER GRAN 0F DRY TISSUE AFTER 30 AND 46

(Values given are

DAYS OF GmWTH IN VARIOUS CALCIUM - STmNTIUM
NUTRI HUT SOIUTIONS.
the average of five plats.)

 

30 days 46 days
1' :- estnent 0.1 cium Strontium 001 ci 1111 St rontiun
__ Top Root Top Root Top Root 'l'op Root
10° 00 .695 .165 .004 .002 .715 .245 .002 .004
75 Cu .556 .150 .002 .002 .505 .060 .004 .002
50 c. .555 .070 .004 .002 .525 .065 .002 .004
25 0- .570 .060 .004 .004 .255 .040 .004 .004
75 00. + 25 Sr .655 .215 .152 .054 .640 .200 .145 .095
5° 0. + 50 Sr .555 .165 .227 .154 .470 .145 .259 .165
25 G. + 75 s. .595 .110 .556 .172 .550 .080 .574 .177
1 00 Sr 0 305 0 075 0 556 0 243 0 205 0 050 0 531 0 232
75 SP 0220 0035 0300 .213 0135 0020 0343 0159
50 Sr 0170 0025 0200 0104 0120 0020 0206 0145
26 ST 0120 0025 0109 0057 0090 0020 0107 0104
0 Co. + 08:- .070 .020 .002 .004 .055 .015 .000 .004

bd

 

 

08. So. So. 9:. N8. «8. So. on”. 80. So. .80. 92. .6 o + .6 o
80. 0mg. 03. 03. 000. 001 Ono. 03. 2.0. 0:. 03. 0mm. .5 mu
«5. wow. omo. 0mm. nvu. 00w. Ono. 00m. $3. 00m. 03. 03. km on
mma. 00¢. 0N0. can. cud. as. Ono. 3m. 03... «0». ave. 00m. .5 ms.
000. 2.0. 0m0. mg. 31 >00. 000. 00a. SH. 000. 03. 000. um 00...
00.... mum. 03. $0. #3. mam. 000. 000. 0:... 0.9. 000. 00a. hm ms +. 00 mm
So. 8». 3.0. 00». 000. mg. 050.. 000. 30. Sm. 00a. 0mm. pm on + 00 00
~00. 0:". $0. 000. «no. EA. 000. 000. .30. 0.54. 0:. 00». .8 mm + .00 E.
30. 30. 30. 00¢. «00. mac. Ono. 00». 30. 30. Ono. 00». .00 on
N00. 500. $0. 03. 000. ”No. 000. 050. 0.8. 000. 00H. 0.3. 00 on
N00. «00. 2.0. One. N00. 03. 050. 00». >00. 30. Oma. 03.. do or
000. 000. 000. mum. ~00. 0H0. 00H. 000. 000. 500. can. amp. 00 00a
900m 00m. poem no“. 900m 009 000m non. voom non. poem non.

53:0; pm a: «0 H00 Sapflnhvm .5 an H00 an .3893 a: «03 pafifioua

.53 8 SE. 8 :5 3

 

 

HPN H.349

1'!
HIV

“avian 0>C 00 000.3»0. .05 0...- .Ubau 00:75

magnum 95352 gnazaumgio
mbogb HM “3380 he man 00 GE we .00 5:4. whammy Ea no :58 E

waiébggaag m< ammmmmxm $924.5 an ac 95928 33928.5 924 38.7.0

Fig. 15.

Tomato piant celcium end strontium
content in relation to totai dry
weight after 55 days of treatment
witn verioue calcium-strontium
nutrient seiutione. (Mean of five
plants.)

 

69

 

 

CONTENT

STRONTIUM

AND

CALCIUM

RELATION

PLANT

TOMATO

WEIGHT

DRY

TO

IN

 

 

 

 

 

 

 

g 0 *0
mo... up 0111019

tops

Calcium In

 

.80 ’

 

 

 

 

 

 

a 5
O s
3 2 2 0 a)
g ..
.5 .
E E 25:3:3:3:i:3: (O
E 3 3 ///////.
h 0- ‘-
3 .- I)
:3 g 3 mm» N
- h b
a 0- 0—
0 «n m ................... .
aaaaaa “
m
‘- 2% la uwmn n
............... h
A%%%%%d¢hd¢ ”
'-I I)
mmmn s
............... 5
/////////////////////,;});};;;;2};;;;);;
n 55 o
llllllllllllllll. 9
l ........................ . .
A%%%%%%hdhfid"m
I
~-:‘:-:-:«:-:-:- 9
mmmmmwmmmmuflp.
l ;.;.;.;.;.;.;.;.;.;.;. ° 5
5%%azahnfl’m
uwmmmmwmmmmmmmmfizg
Ifijjfifi: o b
//////////. 0 m
'-:-:-:-.-:-:-:-:-:-:-:-:-:-:-:-:-:-:-:- n I)
IMWWWMWWWMWMWMMWMWMMn~N
O
O
nmmmmmmfl 8
O
0
mwmmmmmwfifi 8
O
O
".;:;:;.'f{:.' I)
ummwmwmwmmmmmmmm N
O
0
.‘:ij::;3:::::.:}:;:;Iflfifzfifigiffifij3:2 O
mmwmwmmmwmwmwmmmwmmmmm 9
o 0 o o
9 t N 9
111046 100 swungnbemm

O N 53

S () L U 1'

I E I! T

N l] T' R

 

 

Figure 15

Fig. 16.

Beat plant calcium.and strontium
content in relation to totai dry
weight after 90 days of treatment
with various calcium-strontiumm
nutrient solutions. (Mean of five
plants.) v

7O

 

 

I F
.. :3 3 '5 o
g g 3. 9. 0(7)
. b .E .5 llllllloo
- - U)
E E E .5 .5 ,2: «5
5 3 C c
l— ’_:'_. ‘5; 3 g mmmu. '3 z
E I a w o
| /// :;:;:;:;:;:;:;:; (7)
_ ill/II/l/I
llllllllllllll.. o
2 2:9 WWW” ‘0 3
D — 2 I)
..: LIJ llllllllllll. h _.H
O /////////////////////////////,;;;2 O
n _ o
m nmmmnm. 9
m a: - ° ~
o ////////////////////J22222, 0 a)
llIllIIlllllllllIlllllllllllll... '3 2
Q - '
.. O b
E O //////////////// 0 m
o
I'— -- IIIHHHIHHHII“H”HI”"l”"lllllllml' .3 g n
.... o
2 mum
2 C2) llllIllIlllllllllIllllllllllllllllllllllllllllllllllllllll..... 2 8
0 —
< < .
0 _J Illlllllllllllllllllllllll. "N’ z
LIJ
o: o
0
Z IIllllllllllllllllllllllllllllllllllllllll., 8 —
<
_l E 8 a:
.- lllllIIIIIIIIIIIIIIIIIIIIIIIIIIllllllllllllllllllllllll. '2 t-
l— 3 3'
t3 llllllllIllllllllllllllllllllllllllllIllllllIlllllllllllllll...... 9 2
m g 2 o 3
-' o’ o o o o
wagon hp smug mom 10d swegounbegmw

 

  

 
 
 

 

 
 
  

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Figure 16

71

was less pronounced in beet roots than the other tissues.
Conversely, the addition of calcium.to the 75, SO, and 25
strontium levels resulted in increased strontium accumula-
tion in tomato tops and beet tops, had little effect on the
strontium content of tomato roots, and depressed the stron-
tium.content of beet roots. Thus it would appear that cal-
cium.and strontium, when present together in a nutrient
solution, generally aid the accumulation of each other in

beet tops and tomato tops.

Egperimentgj

Objective

To analyze field grown plants for strontium.and calcium.
The determination of strontium should show whether the soils
in the vicinity of East Lansing, Michigan, contain any appre-
ciable available strontium. Calcium.analysis will allow
comparison between field grown plants and those grown in sand

culture greenhouse experiments.

Materials and Methods

Tomato, beet, pepper and eggplant samples were collected
from three locations on September 23, 1953. Samples one
through six came from.aeveral locations at the Horticulture
Farm, Samples seven through ten were taken from the author's

home garden, and samples eleven and twelve came from.a garden

72

north of East Lansing. Duplicate four gram samples of oven
dried tissue were ashed in the muffle at 600° C for twenty
hours and taken up in one percent perchloric acid in the

usual manner. Potassium, sodium, calciwm and strontium in
these solutions were determined on the flame spectrophotometer
by the method described earlier. The potassium and sodium
determinations were used only to correct for flame inter-

ference with calcium.and strontium.

Results

The plant tissue concentration of calcium.and strontium
expressed as percent of the oven dry weight are shown in
Table XVII. A few samples contained trace amounts of stron-
tium.but in most samples none could be detected by the flame
spectrophotometer method. These data indicate there is very
little available strontium.in the soils of this area. The
analyses show that the test plant leaves contain considerable
calcium while tomato fruits, pepper fruits, and best roots
are normally low in this element. Samples two and four,
where best leaf blades and petioles were analyzedseparately,
show that most of the beet leaf calcium is contained in the
blade.

 

7.5

TABLE XVII

CALCIUM AND STRONTIUI GNTENT 0F TOMATO, BEE, EBGPLANT AND
PEPPER PLANTS GROWN UNDER FIELD (DNDITIONS

 

 

Snple Flat Tissue Percent of the Dry Weight

Calcium Strontim
1a Beet roots 0.06 .004
b Beet tops 1.54 .000
2a Beet leaf blades 1.67 .000
b Beet leaf petioles 0.28 .002
3a Beet roots 0.06 .002
b Beet tops 1.41 .000
4a Beet leaf blades 1.42 .000
b Beet leaf petioles 0.24 .000
5a Pepper fruits 0.02 .005
1: Pepper leaves 2.35 .004
6a Tomato fruits 0.02 .004
1) Tomato leaves 4.06 .000
7a Beet tops 2.3 .000
b Beet roster 0.18 .000
8a Tomato fruits 0.03 .000
1) Tomato leaves 4.78 .000
9a Pepper fruits 0.04 .000
b Pepper leaves 4.67 .000
10a kgplmt leaves 3.88 .000
III BO“ tops 109‘ .m0
b Beet roots 0.09 .000
12a Tomato leaves 4.42 .(DO
15 Tomato fruits 0.03 .002

 

7h

B. Comparative Absorption and Translocation of Radio-
strontium, Radiocalcium and Radiobarium in Tomato, Beet

and Bean Plants as Determined by Autoradiography

Experiment_g

Objective

The semi-quantitative determination of calcium, strontium
and barium absorbed and translocated by bean, tomato and best

plants following application to the roots or leaves.

Materials and Methods
Plants were grown in the greenhouse during the fall and

winter of 1951-1952, and treated when of sufficient size to
bepressed flat on an eight by ten inch area. Bean, tomato
and beet plants were treated with cans and Sr89 while only
tomato and.beet received Balho. The plants were harvested,
dried and prepared for exposure to X-ray film.as described
earlier. Details of the treating solutions and times of ex-
posure to X-ray film are given in Table XVIII. A low calcium.
nutrient solution.was used for'growing all bean plants while
tomatoes and beets were grown at two levels of calcium. Bean
plants were treated in three ways by (a) dipping the first
trifoliate leaf in the isotope solution, (b) dipping the first
pair of leaves, or (c) adding the isotope to the root medium.
Tomatoes and beets were treated by either dipping the entire
foliage or adding the isotope to the root medium. Bean

7b

 

 

m H Ono. $8.0 no .0 o¢Hsm voom
m one. 8.0 m .o mwum use

v one. smofi o. H menu wanna ..N cannon.
s and. 3.6 o.H . mmam

b 30 . mm .o o . H menu Hm no Hlo H nee m

A933 THE new 3.530?
05:. mfiBHdeaonHHHa—v 0.3%....» no .3 7d: hem
0.3.393 #830 Hm 0 H963 pom no Hana one is no «.3098 H5 amoeba H 98.5.09;
EHHeH heaux mo pageant-yoga nogeuvnoocoo oaovon HOHvem IOHuem no oven #9 HA

r

guangabd may mom away mmbngm GE .Ecmoggofl: mam

fiance magma ma ENHAMB wonEHOw mmanmHOHQm ho 82.35583

nan mafia

76

plants were harvested at 8, 2h, 60 and 120 hours after
treatment while beet and tomato plants were harvested at

8, 21+, and 96 hours. Root applications consisted of five
milliliters of the treating solutions for beans andisen
milliliters of each treating solution for tomatoes and beets.
All X-ray films were develOped for six minutes in Kodak
X-ray DevelOper following exposure to the radioactive

plants.

Results

Autoradiograms of radiocalcium and radiostrontium

applied to bean plants are shown in Figures 17 and 18.

These show the distribution of the two elements is very

:much alike, and neither one exhibits much translocation

frmm the site of_a leaf application. The X-ray negatives

of some foliar treated plants showed slight traces of radio-
activity in the stem and other plant parts but the impression
on the film was usually too faint to be reproduced photo-
graphically. _This movement of trace amounts was independent
of time, often being higher at 8 and 2h hours after treatment
than at 120 hours.

Root applications, on the other hand, showed absorption
and translocation of the radioisotope to be directly propor-
tional to treatment period. The distribution of radiocalcium
following root absorption was very uniform throughout the

bean plant; old leaves accumulating as much as young leaves.

Fig. 17. Autoradiograms of radiocalcium.(0ah5)
in bean plants.

Top:
Center:
Bottom:

Left:
Right:

First trifoliate leaf dipped in
isotope solution.

First pair of leaves dipped in
isotope solution.

Isotope added to root medium.

2h hours after treatment
60 hours after treatment

 

77

 

Figure 17

 

Fig. 18. Autoradiograms of radiostrontium (Sr

89,

in bean plants.

Top: ,
Center:
Bottom:

Left:
Right:

First trifoliate leaf dipped in
isotope solution

First pair of leaves dipped in
isotope solution

Isotope added to root medium

an hours after treatment
60 hours after treatment

 

78

 

Figure 18

79

Radiostrontium showed a slight tendency to accumulate in

the vascular tissue but was otherwise uniformly distributed
throughout the plant. Both calcium and strontium accumulated
in the nodules on the bean roots.

Tomato plants harvested 96 hours after treatment with
radiocalcium (Cal‘s), radiostrontium (Sr89) and radiobarium
(Balho) are shown in Figures 19. 20 and 21 respectively.
There was no detectable downward movement of these elements
from a leaf application to tomato plants. The initial cal-
cium content of the plants had considerable effect on the
uptake of the radioisotopes from the root medium. Plants
low in calcium took up more Cal‘s, the same amount of $1.89,
and less Baum than plants higher in calcium. Radiocalcium
and radiostrontium in the plants increased with the treatment
period. Radiobarium content, on the other hand, was the same
at 8, 2h, and 96 hours. Similar to beans, translocation
from the roots to all tomato plant parts was general for all
three isotopes, but distribution within plant parts varied.
Calcium was distributed uniformly throughout the plant while
strontium and barium accumulated in the vascular tissue.

Beet plants treated with the three radioisotopes and
harvested 96 hours later are also shown in Figures 19, 20
and 21. Downward novement from treated leaves into the small

fleshy root occurred with all three isotopes although the
darkening of the X-ray emulsion by Cal"5 was so slight that it

Fig. 19. Autoradiograms of tomato and best plants
harvested 96 hours suBgequent to treatment
with radiocalcium (Ca J.

heft: Root application
Right: Foliage application

 

80

 

Figure 19

Fig. 20.

Autoradiograms of tomato and beet plants
harvested 96 hours subsgguent to treatment
with radiostrontium (Sr ).

heft: Root application
Right: Foliage application

 

Fig. 21. Autoradiograms of tomato and best plants
harvested 96 hours su sequent to treatment
with radiobarium (Ba .

Left: Root application
Right: Foliage application

 

82

 

Figure 21

5)

could not be reproduced (Figure 19). The amount of downward
movement by all three isotopes was apparently the same at

8, 2’4, and 96 hours. The quantity of radiostrontium and radio-
barium taken up by beets from a root application appeared also
to be the same at all three harvest periods while radiocalcium
progressively accumulated at each succeeding harvest. Only
radiocalcium absorption was affected by the initial calcium
content of the best plants. At eight hours the low calcium
plants had accumulated considerably more Cal45 than high cal-
cium plants but by 214 hours this difference had disappeared.
When absorbed by beet roots, calcium and barium spread uni-
formly throughout the leaves while strontiun accumulated in
the leaf veins and appeared to be more concentrated in the
younger leaves. Barium is accumulated in large amounts in the
stem and transition zone between the root and the stem of

the beet plant.

Eeriment 5

Objective
Determine the distribution of radiostrontium and radio-
calcium in best roots after addition of radioisotopes to the

nutrient solutions in which the roots were growing.

Materials and Methods
Beets were grown in the greenhouse in six inch pots

filled with sand. Each clay pot was set in a two quart enamel

pan partly filled wflmlfioagland's nutrient solution. Ten
microcuries of radiostrontium.(Sr90) were added to each of
the nutrient solutions August 2, 1952, when the beet roots
reached a diameter of five to six centimeters. Beet roots
were harvested 36 hours later. Another set of plants were
grown the following year and these were each treated with
50 mdcrocuries of Gel"5 on August A, 1953. and harvested
after 80 hours. Transverse and longitudinal sections
approximately 1 1/2 millimeters thick were cut with a home-
made vegetable slicer. Radiostrontium treated sections
were dried under pressure with.heat lamps while the radio-
calcium sections were dried under pressure in a circulating
70°C oven. The latter method was found the more satisfactory.
Shrinkage amounted to about ten percent of the diameter.
Radiostrontium.treated sections were exposed to X—ray film

for 19 days and radiocalcium sections for 33 days.

Results

Distribution of radiostrontium and radiocalcium.in the
fleshy roots of beets is shown in Figure 22. A quantitative
estimation of the radiostrontium or calcium in these sections
is not possible because of differences in beta particle energy
and conditions of treatment and exposure. The pattern of
distribution, however, is very similar for the two elements.
The greatest accumulation is in the basal parts of the root

and in the stem.portions with.most of the upward movement

F180 22.

Autoradiograms of transverse and longi-
tudinal sections of beet roots showing

the distribution of radiostrontium

(above) and radiocalcium (below) following
isotope additions to the root medium.
(Actual diameter of roots 5-6 centimeters).

._.— -...

 

Figure 22

86

taking place in the central zone of primary and secondary

vascular tissues or in the tertiary tissues at the periphery

of the root.

Experiment 6

Objective

Determine the pattern.of strontium absorption by tomato
fruits following root application and direct treatment of

the intact skin.

Materials and Methods

Two tomato plants from.the high calcium series of sub-
sequently described Experiment 9 (Page 99) were used. The
plants were grown in Hoagland's nutrient solution until
the first cluster fruits were six to seven centimeters in
diameter. Fruits were set with a 30 parts per million solu-
tion of p-chlorophenoxyacetic acid and consequently were
mostly seedless. However, one fruit of the soil treated
plant contained seeds. (See bottom.two sections, Figure 2h)
The fruits of one plant were painted twice on August h, 1953,
with the radioactive strontium.ahloride dipping solution used
in Experiment 9 (see page 100). According to the counting data
the application.was approximately 0.25 microcuries of Srgo
per fruit. Treatment of the other plant consisted of adding
30 microcuries of Srgo to the nutrient solution. Painted

57

fruits were harvested at 36 hours and fruits from the root
treated plant were collected after 80 hours. Approximately
1 l/2 millimeter median transverse sections were cut from
the fruits and dried in a 70°C forced air oven. The Sr90
painted fruits were exposed to X-ray film for seven days
while fruit sections from the root treated plant required

an eighteen day exposure.

Results

The absorption of radiostrontium.through the skin of
tomato fruits is demonstrated by Figure 23. A considerable
amount of‘Sr90 moved into the interior of the fruit without
accumulation in any particular tissue. Figure 2h shows the
distribution of radiostrontium in tomato fruits following
absorption by the roots. The greatest concentration was in
or near the vascular strands. There was no movement into

the seeds.

 

F189 23 0

Distribution of radiostrontium.(3r9°) in
tomato fruit 36 hours after painting radio-
strontium cn the surface. (Actual diameter
of fruit 6 centimeters.)

Top : Autoradiograms
Bottom: Photographs of the fruit sections

 

 

 

Fig. 2a.

Distribution of radiostrontium (Sr9o) in
tomato fruits 60 hours after radiostrontium
application to the plant roots. (Actual
diameter of fruits 6-7 centimeters).

Left: Autoradiograms
flight: Photographs of the fruit sections

 

89

90

C. Comparative Absorption and Translocation of

Strontium, Calcium and Barium in Tomato and Beet

Plants as Indicated by Radioactive Isotopes

Experimenth

Objective
Determine the relative uptake of radiocalcium, radio-
strontium and radiobariunxby the leaves and roots of beet

plants during a four day treatment period.

Materials and Methods

Beets were seeded in a flat of sand on June 19, 1952,
and pricked off on July 1h, into six inch clay pots filled
with.Wausau Quartz #8. The pots were placed in large painted
metal pans containing one to two inches of Hoagland's nutrient
solution. On August third, one-half of the plants were
changed to a nutrient solution without calcium. These two
groups of plants will be referred to hereafter as "high cal-
cium? and~"lcw calcium” plants. All plants were treated on
August 16, 1952, and harvested four days later.,

Treating solutions were made by adding one microcurie
per millilieter of Cans, or Sr90 and 0.16 microcurie per
milliliter of Balho respectively to 0.0272 molar solutions
of CaClZ, SrCl2 and BaClz. Thus the treating solutions had
the me concentrations on the basis of chemical equivalents.

Specific activities of these solutions were 0.93 microcuries

9i

of Cal"5 per milligram of calcium, 0.h2 microcuries of Sr90

per milligram of strontium, and 0.0u3 microcuries of Ban+0
per milligram of barium. Plants were selected at random

and all treatments werereplicated four times. Roots were
treated by adding ten milliliters of the treating solution

to the plant's nutrient solution held in a two quart pan.
Foliage treatment consisted of inverting the plant and dip-
ping all leaves in the treating solution. Inverted plants
were supported in this position until the leaves were dry.

It was calculated that approximately two milliliters of solu-
tion remained on the leaves.

All plants were harvested after 96 hours of treatment.
Foliage dipped plants were divided into two samples, leaves
and root; while root treated plants were divided into three
samples, the three or four youngest leaves, the remaining
leaves, and the root. Samples were dried at 70°C, weighed
and.prepared for counting. Ban“o was counted as the dried
barium.carbonate precipitated from a solution of the plant
ash; C_a""5 was counted as the ash of ground tissue; and Sr90
was counted simply as dry ground tissue. Grinding was done
in.a Wiley mill using a hO-mesh screen. self-absorption
curves were plotted for all three materials, and then sam-
ples small enough to have little or no self-absorption were
'usedm Radiobarium.and radiocalcium were counted in a Tracer-

lab, Model SC-lB, autoscaler and radiostrontium.was counted

 

 

{I

 

92

in a Nuclear Instruments and Chemical Corporation Ultrascaler,
Model 172. In all cases aliquots of the treating solution //
as reference standards were counted along with the plant tis£////
sue samples. Weight in micrograms of the element in the

plant tissue sample derived‘from the treatment was calculated

from the known concentration of the treating solution and the
measured radiation from the plant tissue and the treating
solution. To more accurately evaluate the ionic absorption,

micrograms were converted to microequivalents by dividing by

the equivalent weight of the element.

Results

Calcium, strontium.and barium.absorption by best leaves
and roots is shown in Table XIX. ’Flame spectrophotometer
analysis showed that ”high calcium” plants contained 0.86,
1.59 and 0.11 percent calcium in the dry tissue of young
leaves, old leaves and roots respectively. Comparable "low
calcium” plants contained 0.19, 0.9h and 0.0a percent calcium
in these same tissues. In spite of this wide difference in
plant calcium content there was very little difference in
radiocalcium, radiostrontium.or radiobarium absorption be-
tween "high calcium” and "low calcium” plants. The 160 parts
per million of calcium in the "high calcium” nutrient solu-
tions also had no effect on root absorption of the isotope
treatment material. The equivalent amounts of the three ele-

ments translocated to the leaves from a root application have

93

 

mmfi om.m 0m .0 60¢ .mNH 05 as. .n E. J mm.» Poem

 

 

 

 

mmé «n4 3.0 .02.. .3." 0.5. 8.” meta... 25m 0253.. one
2.; mm; 3.6 3.3 .3» as: 8.0 8.” mo; 853 was.» 38m
€5.30
$0.0 8.0 «0.0 m.» moo m6 hogv mm.~ no.» poem HON
mmdm maém HOAX" .onnm .mvNN .oow moJ ma.» bin mokooa :4 owswaom -
31m 00$ 3.0 .KM .53 m.m 34 «m.» an; poem
wo.m wmzv $20 .oea .Nma m.w Hm.» mm.m «m.» worse vac
mné moi. «wé .mmm .03 m6." ma; mm.o em.o aches." 50» apoom
SD53
No.0 3.0 «$6 H.H m.o m.m mm.» mm.» mm.» noom WWW-m.
mmém 00.3. mogm 6me 52% .mmm mm.» mm.» owé schema :4 owsfluoh
am am so am am no em am do
mummwp zoo mo Scum 053.3. to no p.39 op venous ovumdm
at: Waging/33033 Saw you afieawoaofi Aguwv poms cmopomH no cover»
pgspmonp omopomw cargo???“ on» 80.5 “Emacs to ten £83 dadoavuhpflz

webmaco snowman. use gapsoawm £533

 

 

Aesowpeozmon noon Mo owsuohé

BnHOBOmH m>Hpb<oH9E Mm 895 HQZH m4 mafia ammm
mo mecca 944 mgr/EH Mm ”Egm 9% SDHBZQEM «$ng mo SHBBEHmHam 92.9 EHEowmd

XHK NAB;

9’4

a Ca:Sr:Ba ratio of about l:10:5 while the roots contain the
ratio 1:10:20. The high value for barium content of roots
suggests that part of it may be adsorbed on the surface rather
than absorbed into the roots. The autoradiogram in Figure 21
(lower left) also shows that barium accumulates in the roots.
All three elements were approximately twice as high in the
young leaves as the older leaves. There is an indication of
downward translocation of all three elements from.a foliar
application but quantitatively it amounts to no more than

a trace of that applied.

Egperiment 8

Objective

To study the absorption and translocation of strontium

by the fruits, leaves and roots of the tomato.

Materials and Methods

Tomato seeds were started in sand June 19, 1952. Seed-
lings were pricked off into six-inch pots containing Nausau
Quartz #8 on July fourth and transplanted to two-gallon crooks
of Flint-Shot sand on August fourth. A four-quart, enamel
pan was placed under each crock and contained a reservoir of
Hoagland's nutrient solution. On August tenth, one-half of
the plants were started on a nutrient solution containing no
calcium so there would be a "high calcium” and a "low calcium”

series of plants. During the period of August 6 - 12, fruit

were set on the first cluster by dipping the open flowers

into a 30 ppm.solution of p-chlorophenoxyacetic acid.

soon as fruit set was assured all u8 plants were topped,

As

leaving two leaves above the fruit cluster and all auxiliary

shoots were removed.

plants were supplied calcium occasionally to arrest the

During late August the "low calcium"

blossom-end rot of the fruit that developed in the "low cal-

cium” series.

When the clusters were pruned to two fruits

prior to treatment, all abnormal specimens were removed.

The

fruits on all plants were nearly fully developed when treated.

Plants were similar to the one shown in Figure 25 (page 103)

except that there were only two fruits per cluster.

The radiostrontium treating solution consisted of

0.0272 M SrCl2 containing one microcurie of Sr90 per milli-

liters

per milliliter and had a specific activity of O.h2 micro-

curies of Sr90 per milligram.of strontium.

replications of eight treatments at each calcium level.

treatments follow:

1.
2.
3.
u.
S.
6.

Both fruits dipped in Sr

90

Both fruits dipped in Sr9o

The
The
The
The

two
two
two

two

leaves above fruit
leaves above fruit
leaves below fruit

leaves below fruit

solution three times.

solution once.

cluster
cluster
cluster

cluster

dipped three
dipped once.
dipped three

dipped once.

This solution contained 2,383 micrograms of strontium

There were three

The

times.

tmeSO

9b

7. Twenty milliliters of treating solution added to
the root mediums
8. Control. No Sr90 added. Samples to be analyzed
for total calcium.
The three applications in treatments 1, 3, and 5, were made
on successive days. Contamination of untreated plant parts
was prevented by covering them with pliofilm.while the leaves
or fruits were being dipped and dried.

All plants were first treated on August 31, 1952, and
harvested on September 13. Originally it was intended to
continue treatments until fruits ripened but due to an un-
fortunate accident, nearly all the "high calcium” plants died
from lack of water on or about September eighth. Therefore,
the treatment period for "high calcium” plants was about 8
days and for "low calcium" plants 13 days.

Samples collected were the fruits, the two leaves above
the fruit cluster, and the two leaves below the cluster.
Peduncles were collected as a separate sample in the soil and
control treatments. The dipped fruits from treatment 2 were
skinned by dipping them in hot ten percent potassium.hydroxide.
Treatment 1 fruits were washed thoroughly with soap and water
to remove excess treating solution. Dipped leaves were not
counted. All other samples were dried, ground in a Wiley mill,
and counted as dry plant tissue with the Tracerlab autoscaler.
Tissues from.control plants were analyzed for calcium.in the

usual manner using the flame spectrophotometer.

97

Results
Flame photometer analysis of checkiplants showed the fol-

lowing calcium content on a percent dry weight basis.

Fruit 2 leaves 2 leaves Peduncle

 

above below and calyx
High calcium.plants 0.05 3.05 3.29 0.86

Low calcium.plants 0.0h 1.59 1.71 0.u6

These data show there was a considerable difference in the
caloium.content of the two groups of plants. The micrograms
of strentium in various plant parts are shown in Table XX.
Dipped leaves were not counted but an estflmation.of the

amount of strontium.applied can be obtained from.Experiment

9 (page 109). There it was found that two leaves, similar in
size to the ones here, would retain about seven milliliters of
solution from.a single dip. Therefore the single dip leaf
treatments would be approximately 16,000 micrograms of stron-
tium and the triple dip three times as much.

The data in Table XX show that strontium is absorbed
through the skin into the fruit tissues but does not move into
the leaves above or below the fruit cluster. Strontium.applied
to the leaves of plants low in calcium does not move out of the
treated area into other leaves er into the fruits. Plants

high in calcium.ehow translocation of very small amounts of

98

TABLE Li

THE ABSORPTION AND Tamswculou or sraonrmm BY THE FRUIT,
Laavm mp ROOTS or mum is INDICATED BY 8:”

(Average of three replications)

____-

Strontium Micrograms of strontiun per gram of

 

 

Treatment Plant Part ._ dry tissue ‘—

High calciun plants Lew calcium plants
Fruit dipped 5 times Fruit 85 95
2 leaves above 0 0
2 leaves below 0 0
Fruit dipped once Fruit interior .‘50 23
2 leaves above 0 0
2 leaves below 0 0
2 leaves above fruit Fruit 0 0
Cluster dipped 3 times 2 leaves below 1 0
2 leaves above fruit Fruit 0 O
Cluster dipped once 2 leaves below ' 6 0
2 leaves below fruit Fruit 1 0
Cluster dipped 3 times 2 leaves above 2 0
2 leaves below fruit Fruit 0 O
Cluster dipped once 2 leaves above 0 0
One root medium Fruit 14 4
addition of 20 2 leaves above 527 207
microcuries and 2 leaves below 360 195

48,000 micrograms Peduncle and calyx 353 75

99

strontium into other tissues. Selected tissues of plants high
in calcium absorbed nearly twice as much strontium from a root
application as plants low in calcium despite the five day dif-
ference in treatment period. Fruits are not able to accumulate
nearly as much strontium.from a soil application as other plant
organs. Even the peduncle and calyx contained twenty times

as much strontium as the fruit. It may be recalled in this
connection that here again strontium.is similar to calcium.in

that fruits also absorb very little calcium.

ggperiment 9

Objective

To investigate further the absorption and translocation
of strontium by the fruit, leaves and roots of the tomato.
Materials and Methods

Tomatoes were started from seed on March 28, 1953. Seed-
lings were transplanted to sand in four-inch clay pots onfiMay
fifth. They were fed weekly with an all-soluble high analysis
fertilizer (10-52-17) until June first when they were trans-
planted to two-gallon crooks of Flint-Shot sand. Subsequently
they were fed Hoagland's nutrient solution in the usual manner.
Fruits were set by dipping flowers in a 30 ppm solution of
p-chlorophenoxyacetic acid. First cluster flowers were all

set during the period of June 23-29, and second cluster flowers

for treatment #1 were set July 3-7. Minus calcium or low

100

calcium nutrient solutions were alternately supplied to
half of the plants after July first. On July 17 all plants
except those for treatment #1 were topped, leaving three
leaves above the first fruit cluster. Axillary shoots were
removed as they appeared. High and low calcium.uutrient
solutions were continued until fruits of the first cluster
were nearly full size. In final preparation for treatment
the leaves below the first cluster were reduced to six, all
remaining axillary shoots were removed, distilled water was
substituted for the nutrient solutions, and fruit clusters
were reduced to five fruits for treatment 1, four fruits for
treatments 2-7, and three fruits for treatments 8-12. To
facilitate harvesting the leaves were numbered consecutively
up the stem and fruits were numbered from.the stem outward.
The first cluster was always between leaves six and seven and
the second cluster (treatment 1) between leaves nine and ten.
Stem.sections were (1) soil surface to the internode between
leaves three and four, (2) from.this internode to the first
cluster, (3) all stem above the fruit cluster (treatments 2-11)
or from.the first cluster to the second cluster (treatment 1),
and (h) from the second cluster to Just above the sixteenth
leaf in treatment 1. ’

Treating solutions were 0.00375 Molar, containing 329
micrograms of strontium and one microcurie of Sr90 per milli-

‘ 0
liter. Their specific activity was 3.0h.microcuries of Sr9

101

per milligram of strontium. In one treating solution the
strontium was in ionic form.as the chloride; in the other

it was chelated by adding a slight excess of Sequestrene Nah.1

All treating solutions were adjusted to pH 9—10, the range at
which chelated alkali metals are most stable. It was thought
that chelation might facilitate strontium translocation from
the site of foliar applications. Addition of oxalate to
samples of the two treating solutions showed them.to be
different in that strontium oxalate precipitated from the
chloride solution but not from the chelated solution. if
The treatments were as follows:

Q
1. Thirty m1 of Sr’OCl treating solution added to the

root medium. Thesezwere the only plants not topped.
They had 20-25 leaves, two clusters of five fruit
each, and were about five feet in height.

2. Fifteen.md. of Sr9°Cl2 added to the root medium.

3. Fifteen ml. of chelated Srq3added to the root medium.
h. One ml of Sr90012 injected into fruit #1. pt
5. One ml. ofcumlated Sr90 injected into fruit #1.

6. Fruits 2, 3, and u painted with Sr90012.
7. Fruits 2, 3 and h painted with chelated SrgQ.

8. Leaves 7 and 8 dipped in SrgoClz. Q ~

9. Leaves 7 and 8 dipped in chelated $1.90,
10. Leaves 5 and 6 dipped in Sr90C12.

!

1. Tetrasodium.ethylenediamine tetraacetate obtained
from Geigy Company, Inc., 89 Barclay Street, New York 8, New
'York.

102

11. Leaves 5 and 6 dipped in chelated 3:90.

12. Control, no strontium applied. Plant samples to
be analyzed for total calcium.

Eight plants comprised each treatment, including four "high
calcium" and four "low calciumfi'plants. A typical plant is
shown in Figure 25. The fruit injections were made with a
one-inch 23-gauge hypodermic needle attached to a one cubic
centimeter syringe. In treatments 6 and 7, fruits 2, 3 and h
were painted a second time shortly after the first application
was dry. Non-treated portions of the foliage of treated
plants were protected from accidental contamination by cover- a;
ing with sheets of pliofilm.

Treatments were applied July 2k and 25, 1953. All
above ground vegetative portions were harvested 192 hours
later. The five fruits on both chasters of treatment 1
plants were harvested from.the stem outward at 12, 2h, #8,

96, and 192 hours. Fruits of treatments 2 and 3 were col-

:1 «tr

lected at 2h, h8, 96, and 192 hours and those of treatments 5).
8, 9, 10 and 11 were harvested at 2h, 72 and 192 hours. The I
non-treated fruits of treatments A and 5 weretremoved at 2h,
72 and 192 hours while all fruits on treatments 6 and 7 were
harvested at 192 hours. All leaves, stem sections and pedun-
else of root treated plants were harvested as individual
samples. In the foliage and fruit treatments, leaves near
the treated area were harvested individually while those

farther away were collected in groups of two or three. The

.mwtwi

Fig. 250

Tomato plant typical of those used in
Expertment 9.

Enamel pan contains nutrient solution.

 

Figure 25

 

th

two treated leaves for each plant in treatments 8 to 11 were
harvested together, dried, weighed and then combined as two

90

large samples (ionic Sr90 dipped and chelated Sr dipped) for

radioactive counting. Painted or injected fruits were counted
as individual samples for each plant. Radioactive assay of
these samples was necessary for calculating the amount of
strontium.actually applied. Control plants were harvested on
July 27 and divided into six samples for calcium analysis

by the flame spectrophotometer. There was a total of 1,312
tissue samples for radioactive counting and h8 samples for
calcium analysis. The radioactive samples were dried, weighed,
ground in a Wiley mill and counted as dry tissue in four cen-
timeter Coors capsules.- Counting time was ten minutes for
samples showing little or no activity and less than ten.min-
utes for those with appreciable radioactivity. Samples of all
treating solutions were counted at the same time. These counts
and the known concentration of strontium in the treating solu-
tions enabled the counts per minute per gram of dry tissue to

be converted to micrograms of strontium per gram of dry tissue.

Results

Flame photometer analysis of control plants showed a real
difference in caloium.content between ”high calcium” and "low
calcium” plants. The following amounts of calcium (percent

dry weight) were found:

105

Leaves Leaves Leaves Stem Peduncle Fruit

 

1-3 u-6 7-9
High Ca plants h.h5 3.50 2.98 1.1a 0.61 0.05
Low Ca plants 3-2h 2.1a 1.5h 0.62 0.27 0.03

 

Another indication of a difference between these two
groups of plants was the prevalence of blossom-end rot. Thirty
of the fifty plants grown in the ”low calcium" series developed
blossom-end rot on one or more fruits while only three of the
"high calcium" plants showed symptoms. All affected fruits
were removed when the plants were prepared for treatment.

The only appreciable absorption and translocation of
strontium.was by the roots. Amounts of strontium found in
the above ground portions of root treated plants are shown
in Tables XXI and XXII. These show that the "high calcium”
plants absorb more strontium than "low calcium” plants when
the treating solution is strontium chloride. On the other
Ihand, when chelated strontium.is used, vegetative parts of
”low calcium” plants take up more strontium than "high cal-
cium” plants. These differences are shown in Figures 26 and
27, which also show the great variability in uptake by the
'various leaves of the plant. Figures 26 and 27 also show
that fruits accumulate much less strontium than vegetative
lilant parts. It should be noted in the treatment 1 data
(Table XXI) that the oldest and youngest leaves are lower

ill strontium content than intermediate leaves.

106

 

 

 

 

.«0 8.0 7...: «as .5 as... .8». 0... .3...“
3.0 8.0 7...: 08 .. par... «.3 0.0» a.» ......E
«To «To 7...: 0.: .... per...
.«0 3.0 7...: .3 .« 0...... 0.3 «0» 3 a...
3.0 3.0 7...: «s ... is... 0..» ”.3 a. a...“
«.3 «.«.. 3 ......
...: m.0« « .380... 0.3 a... 2 ...3
”.3 a... «a 0.3
3.0 8.0 7...: «as .... 03.... m.«» «.8 S 0....
3.0 3.0 7...: 03 v 3...... 0.3 a...» 0. «.3
0«.0 we... 7...: a: n 3...... 0.»... 70. 0 e...
$0 8.0 7...: .«v « 2...... a... .....S m a...
3.0 8.0 7...: «c a as... m...” ..S a. ......
72 0.3 e 0....
«.3 m.«« H 32...... CS ..3 u a...”
...: a... . ......
a... ..0« e .53... seam .72 m..« » ......
«.8 ..0« n 83... a... 0.3 0.3 « 0....
«.5. 0.0« « .. .83... .83 0:... e6. H 0....
undead 09.3.3
.530an Ron Susana nwa evalfia madman
#5“ 0.58 EMOHGO lb..— SflOHOO SEE gem Pam

 

come; .30 mo Edam mom
E23093.» no Squamouod—

own-u» be no Esau hem

5.3.5....» «0 05.59.09

 

 

72832530.. .38 go omeaebé

mafia :DHHZDmym mans Ramayana he was ENE agn— neaam 09482.. g Eaama
mo who“. ma. On. antimoodaga 92¢ .0908 emu. um ammommd abnagsm mo 32.58%;

g H.349

1.07

_, n..-

 

 

dooa maod no.0 wood aonun NQHV d vauhm
wmoo mo." ”moo OH.H Aonhn mmv n vflfihm
3.0 :30 05.0 3.: 7...: 03 « ......
maoo ”woo wmoo 0*.0 A.uh£ ¢Nv H vuuhm
vomfi moon won» moon 0H0n560m
womm «cad doON Cod» n nuance. 350%
none mom." OoNN doc» N Tn 8.3600 59m
momo boom wont donb m Mdoq
mowm wowm not” wowd 0 used
m.mN H.5N NoON com» 5 Hang
wow» com» com» ”can w hang
Hon» Goad want womm m «cod
mood m.Oa coma sown ¢ Mdog
Oov¢ Homo Oomd Nam» n Mdog
mod» «.0» scum vonfl N «don
Homa Hooa Nome notm A Mica
383 .953» .233 3.33
a: o 00 kb 25 o
.m H .H HOHG g a SHOflCO RON EMOHGO WEE sham #9.:

 

 

020:» but «0 «Bad 52% 562020
a. 00.3.3. ...m «0 unauwouoi

2...: mu «o ......«m hon .opuaono
m. 003.3. ...m «0 aflouwouoi

 

 

70:03:03.“... .0 no owauohd .230 w @0209 vacancouuv

:bHazomam anflmmd he :2 guano ma 92¢ smug Eda mBmHa hm Bombing ad
myaqfi 09432. be when. mma OH ESQ—magma 95. naoom Emu. Mm 3983a Esp—Oman no 353696“!

MHNN wands

Fig. 26.

F180 27.

Strontium accumulation by the aerial
parts of tomato plants grown at two
calcium levels eight days after the
addition of strontium chloride to the
root medium. (Mean of four plants.)

Strontium accumulation by the aerial
parts of tomato plants grown at two
calcium levels eight days after the
addition of strontium chelate to the
root medium. (Mean of four plants.)

108

 

maroon»: 0! "roman per gram dry weight

 

E men cALcqu PLANTS

I Low cALcmu Puu'rs

 

7C:

 

 

CC}

 

50

 

HIHHIIIIIIIIIIIIHHHIllHllli;illlllllllllilllmllllllllllllill!

 

41>

IIHHHIHH

 

on
9
|

 

N

O

4],
:IW
|

:I ill!l|HH

 

lllllll lllllllllllllllll I ll" lllllllllllllllllll llHHl
a. I II I I lllllll

llIll|lIIIIIIIIIIIllllllllllllllilHII

0‘ 1|lHll||IIIIIIIIIIHIIIIIIIHIHIlllllllH|IIiHHHHIIII
llIlllllllllllllHIIIIIIIIIIIIIIHIHIIHIIhi

 

IHllllllIlllllllllllllllllillll|llllllIIHIIHIIIIIIIIIHHIlllllHM
lllllllllllllllllllllllllHilllllllllllllllllllllHIllHlillll

HHIIIllllllllllllllllllllllllllllllllllllIllllll
llIIllllllllllllllllllllllllllllll||||1H||IH|HI|H

lH!i.IHHHIIlllllllllllllllllllllHHlliiliIJI.‘

a IIIIlllllllllllllllllIHHIIIIH|IlllIIIIIIIIIIHHHHHHIHIIHHlllllHuIIHIIHIHHH.i. lil
HI

‘1 HllHlIIIIllllllllllllllllllIIIIIIHIHHIIHIilll

"' lllll

1:2 3

I E I V E 5 UI
S'E" FR I
SECIIONS

N
b
O
0

 

Figure 26

__

 

Hicrcgroms or strontium per gram dry weight

 

E men cALcmu runs

 

7G I Low cALcqu PLANTS

 

 

6C}

 

 

 

5O

 

 

 

 

41> ---

 

 

ac -

 

 

2()‘

—|

llllllllllllllllllllllllIHII
Illllllllllllllllllll

 

|llllllllllllllllllllllllllllllllllHlllIIIIIIIIIIIHIIIIIIHIIHIIlllllllllllllllllllllllllliIII

llllllllllIlllllllllllllllllllllllllllllllll

 

Hlll|llill||||||llINIIIIIIHIIIIIIHIIIIllIllllllllHIIIHIHIIHIH.I

re
on
J
0 (35;;-.;;_3;..;;;;:-.;:,:;:-.:1first. .
a»
«I
o
co

HIIIllllllllllllllllllllllllllllllllllllllllllllIIIHHHIH

llllllH||||||||||||||||||IIIIIIIH|I|||IHHIIH

a 2
PEDUNCLE
STEM FRUIT

L E A V E S secnous

IO*-_ - - -_ - - _.,-.E. - —— -_ —
l

 

Figure 27

 

l09

The accumulation of strontium in treatment #1 tomato
fruits is shown in Table XXI and also in Figure 28. The
time - accumulation curves in Figure 28 show that uptake is
rapid at first but soon levels off. "High calcium" fruits
in general absorb more than.twice as much strontium.as low
calcium fruits. Accumulation is initially more rapid in the
second cluster of fruits than in the first cluster but after
eight days, first cluster fruits havea higher concentration of
strontium. The decrease in strontium concentration of second
cluster fruits at eight days is caused by growth dilution, that

is, dry matter production exceeds strontium accwmulation.

Summaries of the amounts of strontium.translocated from
the various treatment sites are given in Tables XXIII and XXIV
for high and low calcium plants. Values for the amounts ap-
plied to fruits or leaves were determined by counting a small
sample of the treated tissue,converting this to counts per
minute for the whole treated portion and relating this to
the counts obtained from the treating solution.which had a
known strontium.content of 329 micrograms per milliliter.
From these calculations it was found that two temato leaves
will retain frOm six to eight milliliters of solution from.a
single dip. Painting three fruits twice resulted in retention
of 0.6 - 0.8 milliliters. There was detectable movement to
other leaves when the two leaves above the fruit cluster were

treated, and also into the peduncle when fruit #1 was injected

110

355023 a.“ 30H one swan sundae
Ho waooa mafia—chm no?» on» on 0 am no noapeoflname wcazoaaom
3%an onefioa a.“ agendas—Boos Escape mo nepdm .mN .mam

 

 

hzu3h<u¢h curm< @830:

NO. 00. V'- ON. 00 NF 0' 'N O
P L b L

P P D b

 

.
I N O
0'
"'
"""'
"'
"'

T

 

 

... v.0

I0.0

r 0.0

 

....w r:

.N 5.530 9.23.. 3233 33 ....I... .~ «3.3.6 .321... 2233 :2: III...
._ 5530 .321... 2233 3a..

 

._ «33.6 .35.... 2233 :2: III

83:!

"'89

A80

1H9l3fl

SIVUOOHOIN

$0

”HILNOULS

 

 

II... l‘l' 1"- I‘ll lull I‘ll. lli

 

111

 

 

. 1 as have...
---- ...-.. one: 003 32.88 8&8 o .n .283 .3
.1. --.... 252 32 . 03.820 8&8 m .0 853 .2
08.0 o .m J .n .N .H 8:3 $80 v08 2:320 8&2v m c. .053 .o
80.0 0 .0 .m J 853 ”3.0 «03 8836 8&8 0 .1. 8:3 .0
or-.. run: 082 man @0888 cousin
« .n .N 33....“ .1.
..-..- ...-.. 282 000 3235 881a
v .n .N Sara .0
-....- --.... 28m 8» copies 80.83 a. 39.... .m
3.0 0388a 1.3.0 00» across 831:: a. 3.5 J
3.8 a8. 230 no org :4. 0:: 03¢ essence 8883:? poem .n
5.8 a8 8.3 so She :4 «03 33 octane sausages: poem .N
8.3 go» 3.3 .8 3.3g :4 003 0000 03.83 838:3. poem .H
so no 00 85.5 Assamese «av Aufieuwouo «Iv
soafiofioms 5.3.8.5- 098“ 0093qu confine noon—paces
um .«o penance coalescing» he segues op convened-8.3 vegans um um Me 8.3..—

km

 

 

«BB 85

3:03:0«33 .58 no sue—G

12909 an munm 2.58m oh. mzozko Enid 3A
92¢ BEE .902 20%"— nap—(Am 0.222 3H onacoszuuma 33.3.8.5 mo £25m

HHS mafia

112

1.0;.

 

--- -..-.. 280 0000 000306 8&8 0 .0 .233 .2
..-- ..--.. 08: A000 000.800 8&8 0.0 853 .00
000.0 0 .0 J .0 .0 .H 8:3 03.0 as 03306 8&3 0 ... 82.0.. .0
--- .....- _ 0002 0000 000.33 8&8 0 .... .253 .0
00.0 0 0.3 60258.0 000.0 03 03.320 80500
J .0 .0 .0020 .0
-..- ---- 260 000 03036 803.0 .
J .0 .0 30:0 .0
..-- ..-..- 282 :0 03:06 8.0803 0% pure .0
00.0 30580 03.0 000 00236 802.05 a. 03.... J
00.00 000 0:30 00 3.2a a: 0000 0000 03088 83.03000 080 .0
00.3 03 083 .8 3.30 H2 «00 0000 03036 8300300.. 080 .0
00.2 08 083 00 3.80 02 0000 0000. 03.88 8882000 080 .H
00 0000? 00.5 «ufiuumgo «Ev fies—enmeho .95
8300330 0533.30 evade 0080.55 . 0039?
am no pgouom 00800130..» uo 33000.“ 3 60000309....» 00.3%? um am no Eon pangs?"

hm

 

 

Aegean-02%.— .Bou «0 905

IDES 4492. an. 58 neat: On. mucuukong EA
nzw. BEE .88 30mm mania 2.540.“. 2H BOHSSwSH 35828.5 no :8

>3 mafia

with strontium.chloride. Tables XXIII and XXIV show that
these amounts were no more than traces and they represent
a very small percentage of the strontium applied. Other
than these occasional traces detected, there was no movement

of strontium.away frOmLthe site of foliar or fruit applications.

11“

VI. DISCUSSION

During the course of this investigation it was found that
large amounts of strontium.can be absorbed by plant roots and
translocated to the above ground plant parts. Biddulph and
Cory (’4), Jacobson and Overstreet (29) and Neel _e_1_: _a_l_ (38)
also found appreciable plant absorption of strontium. In
contrast, they report other nuclear fission products to be
only sparingly translocated upwards in plants. The quanti-
tative effect of plant caloium.content upon strontium.absorp-
tion was also studied. The limited absorption and trans-
location from plant leaves and fruits was demonstrated in
several experiments.

According to Comer (13) there are three basic types of
doses that can be administered to an organism: (a) tracer
dose, where the amount of substance administered is small
compared to the normal intake; (b) physiological dose, when
the administered amount is of the same magnitude as the nor-
mal intake; and ~(c3) massive dose, one in which the administered
amount exceeds the normal intake. He stated that the first
two dosage types are usually‘the more desirable. Massive
doses may cause abnormal distribution due to mass action or
‘upset'metabolism. Although there is no established ”normal
intake" of strontium.tor plants, most experimental applications

lib

made in this study may be considered as tracer doses. In
the first two experiments the root applications probably fall
in the category of "massive" doses. These two differ in that
the first experiment treatment period was short while in the
second experiment the treatment period was long enough for
for plant composition to come to equilibrium with the nu-
trient solution.

In Experinent 1 it was found that tomato plants take
up more strontium than beet plants during a four day period.
Both plants accumulated more strontium.in the roots than in
the tops. It should be noted, however, that neither of these
statements held true when the treatment period was extended
to several weeks (Experiment 2). Rediske and Selders (#5)
also found higher accumulation in roots than in leaves.
They demonstrated that most strontium associated with plant
roots grown in solution culture was adsorbed on the roots
rather than absorbed into them. Calcium content of tomato
and beet plants had a very different effect on strontium
uptake by these two crops. Tomato plants high in calcium
took up more strontium.than those low in calcium, while with
best plants a low calcium content accelerated strontium up-
take. Tomato plants high in calcium.translocated a greater
proportion of the absorbed strontium to the upper leaves and
stem.

In Experiment 2 tomato and best plants were grown for us

and.90 days respectively in nutrient solutions containing

lib

various amounts of calcium, strontium, or combinations of the
two. The highest concentrations in the nutrient solutions
were eight milliequivalents per liter (160 ppm.Ca or 352 ppm
Sr). These long treatment periods allowed plant accumulation
to come to equilibrium.with the nutrient solution strontium.
Tomato and best plants will accumulate nearly as much
strontium from high strontium nutrient solution as calcium
from a high calcium solution. The actual maximum.accumu1a-
tions found, measured in milliequivalents per gram.of dry
tissue, were: tomato tops, .712 Ca, .531 Sr; tomato roots,
.2h5 Ca, .232 Sr; beet tops, .915 Ca, .679 Sr;beet roots,
.095 Ca, .172 Sr. These maximum.accumu1ations of strontium
were accompanied by severe toxicity symptoms and.much.re-*
duced growth- When less strontium was accumulated growth
was more nearly normal. Tomato plants had less tolerance for
strontium than beets. With tomatoes the highest strontium
level caused the death of most leaves and a 75 Percent reduc-
tion in dry matter; while the same treatment to beets resulted
in greater accumulation of strontium.but no leaf necrosis and
only Sh percent reduction in dry weight. Hurd-Karrer (27)
noted that strontium.injury to plants is always more pronounced
in tops than in roots. Such was the case here. This may be
the effect of lower accumulation by roots. Both tomato and
best roots normally contain much less calcium than their

respective tops. Root accumulation of strontium.was

117

correspondingly low. However, when strontium toxicity
reduced the dry weight of plant tops it reduced the dry
weight of roots proportionally. This is shown by the lack

of variability in the dry weight Top/Root ratios. The dif-
ference in growth and mineral content also had no appreciable
effect on the percent dry weight of the various tissues.

There were no visual symptoms of strontium toxicity on
tomato plants for the first twenty days and on boats for the
first thirty days. Symptoms were different for the two crops.
The pattern of tomato leaf chlorosis and subsequent necrosis
was unusual since it developed from the leaflet bases toward
the tips on older leaves and in the Opposite direction on
-younger leaves. The youngest leaves were unaffected until
they became two to three inches long. The highest strontium
treatments eventually caused complete death of all older
leaves. Beet leaves were not killed by the highest strontium
treatments but they changed to a dark red color, were smaller
and.rigidly erect. The youngest beet leaves were not affected
until they became one to two inches long.

Rediske and Selders (AS) found that strontium accumula-
tion in bean plants was proportional to its concentration in
the nutrient solution up to 100 ppm, their highest level.
Results here with tomato and beet indicate that this relation
‘is still generally true up to 350 ppm of strontium in the
znitrient solution. Beet roots were an exception in that maxi-

nnun accumulation of strontium occurred at 175 ppm.

we

"" ‘35

lid

Calcium absorption from these various nutrient solu-
tions was also proportional to its concentration in the
solution except where no calcium was added. Here there was
still a small amount of calcium detectable in the plant tis-
sues. Normal appearance and growth of both tomato and beet
plants in the nutrient solution with no calcium and no stron-
tium.was rather unexpected. Apparently impurities in nutrient
salts and the distilled water furnished enough calcium for
normal growth and therefore, calcium can not be considered a
limiting factor for plant growth in any of the treatments.

The three treatments with both calcium and strontium in
the nutrient solution were interesting. The taps of tomato
and best plants grown in these solutions contained more cal-
cium than those grown in the same amount of calcium alone,
and also contained more strontium than those grown in the
same amount of strontium alone. Thus it appears that calcium
and strontium mutually increase the accumulation of each
«other in plant tops rather than depress it as reported by
.haselhoff (22). however, beet root accumulation of strontium
does appear to be inhibited by nutrient solution calcium.
Strontium toxicity symptoms are greatly decreased when calcium
is present in the nutrient solution in spite of the increase
in plant strontimm content. McCool (3h) noted that potassium,
magnesium and sodium.as well as calcium could suppress strontimm

toxicity. The data presented here indicate that this effect

a ... .

ii?

of calcium is a suppression of symptoms rather than a sup-
pression of absorption.
Several investigators, Monargue (3b), Scnarrer and
Schropp (h9) and Walsh (63), found a growth stimulation by
strontium provided adequate calcium was present. In this
study an appreciable increase in best plant dry weight was 30
found in certain calcium—strontium mixtures. Tomato plants fi
showed no such increase, probably because of their greater ' L

sensitivity to strontium.

Chemical analyses for several other elements were made
to determine whether strontium accumulation in.the plant had
any effect on absorption of these elements by tomato and
beet plants. In general, the substitution of strontium for
calcium in the nutrient solution had no effect on potassium or

00pper content. It caused a significant increase in phosphorus,

magnesium.and manganese content. The substitution of strontium

for calcium had no effect on boron in roots but caused asignificant ‘1

boron increase in tomato and best tops. It had no effect on :1
iron content at high strontium concentrations, but at low
strontium.concentrations iron increased in the plant tissues.

Analysis of field grown plants indicate theretras no ;
appreciable strontium in plant tissues collected in this area.
Calcium analysis of these plants showed field.grown plants

to have about the same calcium content as plants grown in

nutrient solutions. Newton (39) reported that plants grown in

solution culture often contain larger amounts of nutrient ele-
ments than plants grown in soil. Therefore, where possible,
the plant composition values determined in this study were
checked against those compiled by Beeson (2) and Goodall and
Gregory (lo). Potassium values determined here were somewhat
higher than found elsewhere but all other elements were very
similar to values given in the literature.

Autoradiographic studies of root absorption by bean,
tomato and beet plants showed that radiostrontium, radio-
calcium.and radiobarium are translocated to all parts of these
plants. This is in contrast to the wheat plants studied by
Spinks‘gt a; (53). They found wheat plants absorb radio-
strontium only into the first two leaves. Strontium and barium
exhibited a tendency to accumulate in the leaf veins. This
was also noted in the dwarf pea by Jacobson and Overstreet
(29). Autoradiograms of median transverse and longitudinal
sections of fleshy beet "roots“ showed that strontium.and
caloium.concentrate in the true root portion and the stem
plate. The main paths of upward transport were the central
zone of primary and secondary vascular tissues and tertiary
vascular tissue Just under the periderm. Autoradiograms of
transverse sections of tomato fruits eighty hours after a
soil application of SrgOCl2 showed strontium.concentrated in
or near the vascular strands. There was no movement of stron-

tium.into tomato seeds. The very limited movement of strontium

121

into seeds has been noted in barley by Walsh (63), in dwarf
pea by Jacobson and Overstreet (29), and in barley and bean
by Neel gt 3; (38).

Four day treatments of tracer amounts of radiocalcium,
radiostrontium and radiobarium to beet plant root media indi-
cated a much greater equivalent absorption of strontium and-
barium than of calciwm. This is undoubtedly due to the rapid
uptake of ions not initially present in the plant. Twice as
much strontium as barium was translocated to the beet leaves
while only half as much accumulated in, or possibly on, the
roots. The concentration of all three elements was about
twice as high in young leaves as in old leaves. A fundamental
difference in the treatments to "high calcium" and "low cal-
cium” beet plants was the calcium content of their respective
nutrient solutions. In the former the nutrient solution con-
tained 160 ppm of calcium while the nutrient solution of the
latter contained no calcium. In spite of this difference,
beet plants took up approximately the same amount of treat-
ment calciwm, strontium.and barium from.hoth solutions. Both
Collander (12) and Hurdearrer (2?) concluded from their in-
vestigations that plants are unableto distinguish between
calcium and strontium and therefore absorb them.in proportion
to their presence in the nutrient solution. This conclusion.
is generally in agreement with the results of this investigation
when plants were harvested after a comparable long period of

treatment (Experiment 2). However, with beets when the treat-
ment period was short, absorption of strontium.and barium

appeared independent of nutrient solution calcium.eontent.

122

beeper (31) and Jacobson and Uverstreet (26) have sug-
gested that soluble complexes or chelates may be important in
cation absorption and exchange by plants. A chelated form
of strontium was prepared to determine what effect chelation
would have on strontium absorption. The complexing agent

used was ethylene diamine tetraacetic acid. In all experiments

.K -1!

up to this time strontium chloride applications to the roots

had resulted in greater strontium uptake by tomato plants

high in calcium. Whenchelated strontium was applied to tomato
roots, plants low in calcium accumulated more strontium in

the leaves and stem than plants high in calcium. This indi-
cates there may be a real difference in response of the root
absorption mechanism depending on the form of strontium pre-
sented to the root surface. This difference in plant absorption
did not extent to fruit accumulation of strontium. Fruits of
high calcium plants contained more strontium irrespective of

the form in which strontium.was applied. e;

._ _
:whs-

The distribution of strontium in a large tomato plant 2‘?
after eight days of root treatment was of some interest.

There was considerable variability in the amount of strontium

 

accumulated by the leaves. The oldest seven or eight leaves
contained less strontium than the next seven or eight leaves
and the youngest leaves were again somewhat lower. The stem
sections and peduncles were fairly uniform in strontium con-

tent and the amount was about equal to that of leaves. Fruit

123

strontium content was about one-twentieth that of the vege-
tative plant parts. This low strontium content of fruits is
consistent with their low calcium.requirement. When fruits
were harvested from two clusters at various time intervals

(1/2, 1, 2, h, 6 days) it was found that initial uptake is
rapid and then the rate of accumulation decreases. Second

cluster fruits contained a higher concentration of strontium

than first cluster fruits at the earlier harvests but bythe end
ofetynsdays the first cluster fruits had the higher concentration.

In contrast to the free movement upwards and the high [4

accumulation from.a soil application,the movement of strontium

from the site of a foliage application is very limited, never

amounting to more than a trace of the quantity applied. hediske

and Selders (#5) treated bean roots with radiostrontium for

a period of time and then withdrew the strontium supply. They

found that once strontium has been deposited in a tissue such

as a leaf, there is no significant redistribution even when 1)
a comparatively high concentration gradient exists. This K
also appears to be the case when strontium is applied directly
to a leaf. Foliage applications of calcium and barium as
‘weil as strontium.were made in several experiments; all with
'very similar results. There was little movement away from
the site of application. Autoradiograms indicated that bean
and beet plants may translocate small.amounts of calcium,

strontium.or barium downward into the untreated portions of

.Lt’q.

the plant, while tomato slants showed no translocation at
all. More precise measurements using an autoscaler indicated
that in a few cases strontium did move in tomato plants but
only in trace amounts.

Both autoradiograms and radioactive counting data indi-
cate strontium can be absorbed into tomato fruits through the
intact skin but can not move out of the fruit. Even injecting
strontium directly into a fruit does not facilitate appreciable
movement to other parts of the plant.

Chelation of strontium had an effect on root absorption
but had no effect on foliar absorption and translocation.
Counting data indicate that chelated strontium was just as
immobile as strontium chloride.

An additional observation was made concerning blossompend
rot of tomato fruits. Raleigh and Chucks (uh) found blossom- I
end rot to be correlated with a low calcium content in the
fruit. In the present investigation blossom-end rot soon
began to appear on tomato fruits when calcium was withheld
from the nutrient solution. As soon as calcium was returned
to the nutrient solution, the increase in "diseased" fruits
was arrested. It would be of interest, in future work, to
determine whether strontium might also prevent the developement

of blossom-end rot when calcium.is limited.

125

VII. SUMMARY

The results of this investigation have led to several
conclusions concerning the qualitative and quantitative as-
pects of strontium absorption by certain horticultural plants.

Strontium applied to the:roots of bean, tomato and beet
plants was absorbed by the roots and translocated to all
above ground plant parts. It is generally absorbed in pro-
portion to its presence in the nutrient solution. Strontium
can be accumulated in tomato and beet tissues in amounts
almost equivalent to the normal caloium.content. At such
high concentrations it is toxic to both plants but the ad-
verse effects are greater on tomato than beet. Strontium and
calcium.in the same nutrient solution mutually favor the ab-
sorption of each other but the presence of adequate calcium
in plant tissues largely masks the toxic effect of strontium.
Plant tissue analysis for several nutrient elements demon-
strated that a high strontium and low calcium.eoncentration in
the plant tissues, as contrasted to high calcium and no stron-
tium, had no effect on potassium or copper content, nearly
always caused an increase in phosphorus, magnesium and man-
ganese and sometimes favored an increase in boron and iron.

Samples from field growngplants contained no appreciable
strontium. The calcium content of these plants was about the

same as the calcium content of greenhouse grown plants.

ul- (:7

“._.

 

126

Autoradiographic studies indicated that radiocalcium,
radiostrontium and radiobarium.are translocated to all parts
of the plant from root application. Strontium and barium
tend to accumulate in the vascular tissues. The distribution
of radiostrontium.in beet roots and tomato fruits was also
studied. Strontium did not move into maturing tomato seeds.

The absorption of calcium, strontium.and barium applied
to the roots of beet plants for four days was independent of
plant calcium content and nutrient solution calcium content.
On the other hand with longer treatment periods calcium and
strontium.were absorbed in proportion to their presence in
the nutrient solution.

Tomato plants high in calcium always absorbed more stron-
tium.than tomato plants low in calcium.when strontium was
applied as the chloride. When applied in a chelated form the low
calcium.plants had a greater strontium uptake. Plant calcium
content had little effect on strontium absorption by beets.

In contrast to the free movement upwards and high accumu-
lation of strontium.from.a root application the movement of
strontium from a foliage application was very slight. Bean
and.beet plants showed a somewhat greater movement than tomato
plants, but in neither was the amount translocated.more than
a trace of that applied. This was likewise true of calcium
and.barium. Chelation of strontium did not increase trans-

location.away from treated tomato leaves or fruits. By means

c... :--.. r - A c‘

.olr.."
.

127

of autoradiography it was demonstrated that radiostrontium
can penetrate the intact skin of a tomato fruit and accumu-

late in the inner tissues.

‘ fa‘ '5‘!
I‘

1.

2.

3.

9.

10.

VIII. LITERATURE CITED

Association of Official Agricultural Chemists. 1950.
Official Methods of Analysis. Seventh Edition.

Beeson, Kenneth C. l9hl. The mineral composition of
crops with particular reference to the soils in.which
they were grown. U. S. Dept. Agr. Misc. Publ. No. 369.

Bibliography of the Literature on the Minor Elements and
Their Relation to Plant and Animal Nutrition. Fourth
Edition. 19h8. Chilean Nitrate Educational Bureau, Inc.,
New York City, New York.

Bidflglph, O, and R. Cory. 1952. The relationship between
total calcium.and fission product radioactivity in
plants of Portulaca oleracea growing in the vicinity of
the atom bomb test sites on Eniwetok Atoll. United States
Atomic Energy Commission Report:UWFL-31.

Bledsoe, R. W., C. L. Comer, and H. C. Harris. l9h9.
Absorption of radioactive calcium by the peanut fruit.
Science 109:329-330.

Blume, J. M. 1952. Radiation effects on plan s grown
in soil treated with fertilizer containing P3 . Soil Sci.
73 3299'303 e

Brenchley, W. E. 1927. Inorganic Plant Poisons and
Stimulants. Second Edition Cambridge University Press.

Brown, J. G., O. Lilleland, and R. K. Jackson. l9h8.
The determination of calcium and magnesiun in leaves
using flame methods and a quartz spectrophotometer.
Proc. Amer. Soc. Hort. Sci. 5231-6

, and . 1950.

-Further notes on the use of flame methods for the analysis
of plant material for potassium, calcium, magnesium.and
sodium. Proc. Amer. Soc. Hort. Sci. 56:12-22.

 

 

Churchill, J. R. l9hh. Techniques of quantitative spec-
Zgogzaphic analysis. Ind. and Eng. Chem., Anal. Ed. 11:
3' 70.

01.0! id- ‘0 Fr fxfi“ '. f I

, in 1“.”
a '.
Pvt“
" g . .-.
'A

11.

12.

13.

15.

16.

17.

18.

19.

20.

21.

22.

23.

129

Colin, H.,£ufl Lavison, J. 1910. Absorption compares des
eels de Baryum, de Strontium et de Calcium par la plante
vivante. Rev. Gen. Bot. XXII:337-3hh.

Collander, R. 19hl. Selective absorption of cations by
higher plants. Plant Physiol. 16: 691- 720.

Comar, C. L. l9h8. Radioisotopes in nutritional trace
element studies I. Nucleonics 3: No. 2. 3244.5.

Daubeny, C. 1835. Memoir on the degree of selection ex— a“.
ercised by plants with regard to the earthy constituents
presented to their absorbing surfaces. Trans. Linn. Soc.

. 2mg: .45. -

.. ..,_ -.no-
5

T. 1861. On the power ascribed to the roots of

 

plants of mrejecting pOsonous or abnormal substances pre- ,
sented to them. Jour. Chem. Soc. of London. XIV: 209- 230. i

Downes, J. D. 19Sh. Growth and certain aspects of the =3
chemical composition of the onion as influenced by nu-
trition. Ph. D. Thesis, Michigan State College.

Evans, T. C. 19h8. Selection of radioautographic tech-
nique for problems in biology. Nucleonics 2: No. 3.

52-58.

Goodall, D. W., and F. G. Gregory. l9h7. Chemical Comp
position of Plants as an Index of Their Nutritional
Status. Tech. Comm. No. 17. Imperial Bureau of Horti-
culture and Plantation Crops, Aberystwyth, Wales.

Guettel, C. L. 19hh. Emission spectrographic equipment ,
used in quantitative analysis. Ind. and Eng. Chem,, ‘ {1_
Anal. Ed. 11: 670-6750 ‘

Hence, F. E. 1933. Less common elements in soils and
fertilizers. Hawaiian Sugar Planters' Assoc., Proc.
53rd. Ann. Meeting. h6-63.

Harris, H. C. l9h9. The effect on the growth of peanuts ;,
of nutrient deficiencies in the root and the pegging zone.
Plant Physiol. 2&3150-161.

Haselhoff, E. 1893. Versuche uber den Ersatz des Kalkes
durch Strontium bei der Pflanzenernahrung. Landw.
Jahrb. 22: 891-8610

Haynes, J. L. and W. R. Robbins. l9h8. Calcium.and boron
as essential factors in the root environment. Jour. Am.
Soc. Agron. hO: 795-803.

21+.
25.
26.
27.
28.
29.

30.

31.

32.
33.

3h-

35.

36.

130

Hinsvark, 0. N., S. H. Wittwer, and H. M. Sell. 1953.
Flame photometric determination of calcium, strontium and
barium in a mixture. Anal. Chem. 25:320-322.

Hoagland, D. R. and D. I. Arnon. 1950. The water culture
method for rowing plants without soil. Calif. Agr. Exp.
Sta. Ciro 3 7O '

Hodgman, Charles D., Editor. 1952-53. Handbook of Chem-
istry and Physics. 3hth Edition. Chemical Rubber Pub-
lishing 00., Cleveland Ohio.

Hbrd-Karrer, Annie M. 1939. Antagonism.of certain ele-
ments essential to plants toward chemically related toxic
elements. Plant Phsiol. 1h:9-29.

Jacobson, L., and R. Overstreet. 19h7. A study of the
mechanism of ion absorption by plant roots using radio-
active elements. Amer. Jour. Bot. 3h:h15-h20.

and . 19h8. The uptake by
‘plants of pIutonium.andsome products of nuclear fission
adsorbed on soil colloids. Soil Sci. 65:129-13h.

 

Eamon, M. D. 1951. Radioactive Tracers in Biology.
Academic Press, New York.

Leeper, G. W. 1952. Factors affecting availability of
inorganic nutrients in soils with special reference to
micro-nutrient metals. Ann. Rev. Plant Physiol. 3:1-16.

Loew, 0. 1898. fiber die Physiologischen Functiqnen der
Calciumsalze. Botanisches Centrbltt. Bd. LXXIV.

. 1903. The physiological role oi?mineral nutrients

In pIants. U. S.I)ept. Agr. Bur. Pl. Ind. Bull. hS.

McCool, M. M. 1913. The action of certain nutrient and
non-nutrient bases on plant growth. I. The antitoxic
action of certain nutrient and non-nutrient bases with
respect to plants. Cornell Univ. Agr. Exp. Sta. Mem.

2 0 121-1700

. 1913. The Action of certain nutrient and
non-nutrient bases on plant growth. III. Toxicity of
variouz cations. Cornell Univ. Agr. Exp. Sta. Mem. 2.
201-21 .

 

McHargue, J. S. 1919. Effect of certain.conpounds of
barium.and strontium on the growth of plants. Jour. Agr.
R08 0 16:183-19’40

37.

38.

39.
ho.
hl.

’12.

AB.

AS.

h6.

h7.

h8.

131

Mitchell, R. L. 19h8. The Spectrographic Analysis of
Soils, Plants and Related Materials. Technical Communi-
cation No. uh, Commonwealth Bureau of Soil Science, Har-
penden, England.

Neel, J. N., B. E. Gilloohg J. H. Olafson, H. Nishita, A.
J. Steen, and K. H. Larson. 1953. Soil-plant interre-
lationships with resBBct tp the upaeke o ission products.
I. The uptake of Sr , Ca 37 Ru Ce and Y9 . Uni-
ted States Atomic Energy Commission Report: UCLA - 2H7.

Newton, J. D- 1928. The selective absorption of inorganic
elements by various crop plants. Soil Sci. 26:85-91.

Norton, R. A. 195k. The absorption, translocation and
distribution of mineral nutrients in the strawberry as
indicated by radioactive isotopes. Ph. D. Thesis,
Michigan State College.

tho—mi 3-“..1 luv u "r d.’
I

0dum, H. T. 1951. Notes on the strontium content of sea
water, celestite Radiolaria, and strontianite snail shells.
Science 11h:211-213.

. 1951. The stability of the world strontium

cycle. Science 11h:h07-h11.

Osterhout, W. J. V. 1907. On nutrient and balanced solu-
tions. Univ. Cal. Pubs., Bot., 2. No. 15. 317-318.

Raleigh, S. M. and J. A. Chucks. l9hh. Effect of nutrient
ratio and concentration on growth and composition of
tomato plants and on the occurrence of blossom-end rot of
the fruit. Plant Physiol. 19:671-678. 5%

Rediske, J. H., and A. A. Selders. 1953. The absorption
and translocation of strontium by plants. Plant Physiol.
28:59h-605.

Ririe, D., and S. J. Toth. 1952. Plant studies with radio-
active calcium. Soil Sci. 73:1-10.

Russell, E. J. 1950. Soil Conditions and Plant Growth.
Eighth Ed. Jarrold and Sons, Ltd., The Empire Press, Nor-
wich, England.

Rygh, 0. l9h9. Trace Elements. I. Importance of
strontium, barium.and zinc in the animal organism. Bull.
Soc. Chem. Biol. 31:1052-1061.

#9.

52.

bio

bu.

55.
SO.

57.

>8.

59.

60.

61..

Scharrer, A. and w. Schropp. 1937. The effects of stron—
tium and barium ions upon theggrowth of some plants.
Bodenkunde und Pflanzenernahr. 3:369-385. Seen in ab-
stract only. Bibliography of the Literature on the Minor
Elements and Their Relation to Plant and Animal Nutrition.
Fourth Edition. Chilean Nitrate Educational Bureau lnc.,
New Xork City, New iork.

Schweitzer, G. h., and B. R. Stein. 1950. Measuring solid
samples of low-energy beta emitters. Nucleonics 7365-72.

Siegel, J. M. l9h6. Nuclei formed in fission: Decay
characteristics, fission yields, and chain relationships.
‘Issued by the Plutonium Project. Jour. Amer. Chem. Soc.

Siri, William.E. 19h9. Isotopic Tracers and Nuclear
Radiations with Applications to Biology and Medicine.
McGraw-hill Book Company, New Iork.

Spinks, J. w. T., E. Cumming, R. L. B. Irwin, and T. J.
.Arnason.. l9h8. Lethal effect of absorbed radioiso-
topes on plants. Canadian J. Research, 26 C:2h9-262.

Spooner, M. A. 19h9. Observations on the absorption
of radioactive strontium.and yttrium.by marine algae.
Jour. Marine Biol. Assoc. United Kingdom 28:587-625.

Stiles, W. 1923. Permeability. New Phytol. 22:128-149.

. 1946. Trace Elements in Plants and Animals.
The Macmillan Company, New Xork.

Stout, P. R., and R. Overstreet. 1950. Soil chemistry
in relation to inorganic nutrition of plants. Ann. Rev.
Plant PhYBiOlo Io. 305-3112.

Suzuki, V. 1900. Can strontium and barium.replace cal-
cium in phanerogams? Bull. Coll. Agr. Tokyo h:69-79,

Ticknor, R. L. 1953. The entry of nutrients through the
bark and leaves of deciduous fruit trees as indicated by
readioactive isotopes. Ph. D. Thesis, Michigan State
College.

Vlamis, J. and h. Jenny. l9h8. Calciwm deficiency in
serpentine soils as revealed by adsorbent technique.
Science 107:5h9.

Voelcker, J. A. 1915. The influence of strontium.salts
on wheat, Jour. Roy. Agr. Soc. England. 76:3hh-3Sl.

62.

63.

6h.

65.

66.

13}

Voinar, A. 0. and L. I. Lazovekaya. l9h2. The bio-

chemistry of strontium and barium. Biokhimiya 7:2hh-25h.
Seen in abstract only. Bibliography of the Literature
on the Minor Elements and Their Relation to Plant and
Animal Nutrition. Fourth Edition. Chilean Nitrate Edu-
cational Bureau, Inc., New York City, New York.

Walsh, T. 19h5. The effect on plant growth of substitu-

ting strontium for calcium in acid soils. Proc. Roy.
Irish Acad. 50B:287-29h.

Wittwer, S. H., and W. S. Lundahl. 1951. Autoradiography

as an aid in determining theggross absorption and utili-
zation of foliar applied nutrients. Plant Physiol. 26:

792-7970
afld H. B. TukGYe 195110 Chap. 15. Radio-

 

isotopes in research on nutrition of fruit crops.
Childers, N. F., Editor. Mineral Nutrition of Fruit
Crops. Horticultural Publications, Rutgers University,
New BMSWiCk, N. J. Pp. 758-77ue

Wolf, B. and S. J. Cesare. 1952. Response of field-

grown peaches to strontium sprays. Science 115:606-607.

WIN \III (I l‘
6 5 5 (

um

“I
”I!
"I
"
Em
H

5
4
1
3
o
3
9
2
1
3

Tm

)lHlellle