GROWTH A N D C O M P O S I T I O N OF T H E S TRA WB E R R Y PLANT
IN RE LATION TO ROOT TEM PER ATU RE

By
A l f r e d Ni^ Roberts

A T HESIS
Submitted to the School of Graduate Studies

of Mic hig

State College of Ag r i c u l t u r e an d A p p l i e d Science
in partial f u l f i llme nt of the requirements
for the degree of

DO CTO R OF PHILOSOPHY

De par tme nt of Horticul tur e
Year

19t>3

GROWTH AND C O M P O S I T I O N O F

T H E STRAWBERRY PLANT

IN RE LAT ION TO R O O T

TEMPERATURE

By
c.•"
A l f r e d N *'1R o b e r t s

AN A B S T R A C T
Submitted to the School

of G r a d u a t e Studies of Mic hig an

State College of A g r i c u l t u r e
in partial f u l f i l l m e n t
for the
DOCTOR OF

and Applied Science

o f the requirements

degree

of

PHILOSOPHY

Department of Horticulture
Year

1953

A l f r e d N. Roberts

The p o s s i b i l i t y of correlating growth response of the
strawberry pla nt to cer tai n ecological

conditions,

namely,

root temperature and con cen tra tio n of the nutrient solution,
w i t h organic

and n u t r i e nt- ele men t composition was studied,.

The relati ons hip b e t w e e n certain of these organic and ash
components and t h e i r influence on the total production of
dry m a t t e r in the root and aerial portions of the plant
during its v e g e t a t i v e growth w a s considered®
Root temperature control was obt ain ed b y growing the
plants in crocks of sand p l u n g e d in temperature control
tanks de signed e s p e c i a l l y for this purpose.
of the nutrient

Concentration

solution was m a i n t a i n e d by frequent renewal

of sand cultures w i t h various concentrations of Hoagland*s
standard nu tri ent solution.

Growth measurements were based

on the total p r o d u c t i o n of dry m a t t e r and the n u m b e r of
runner plants produced.

Organic and nutrient-element

composi tio n of the plant material produced was obtained by
standard analytical procedures.
Du rin g the vegetative p eri od of development,

the growth

of aerial portions of the strawberry plant was closely
correlated w i t h root temperature.
not present for root growth.

Such a relationship was

Therefore,

the top-root

ratio increased w i t h h i g h e r root t e m p e r a t u r e 0
M a x i m u m dry w eight a c c u m ula tio n in b o t h root and aerial
portions of the s tra wb e r r y plant occurred in nutrient solu­
tions of r e l a tiv ely low salt concentration (0.5 H o a g l a n d ’s
so^ition).

However,

normal growth occurred in more concen­

A l f r e d N . Roberts

trated solutions.

On the b asi s of dry wei ght accumulation,

ma x i m u m growth of all aerial parts of the plant during this
vegetative phase of development oc curred at root temper­
atures b e t w e e n 65° and 75° F» regardless of nutrient solu­
tion concentration.

There was no significant difference

in dry weight of roots w i t h i n the range of root temperatures
used in this study (lp5?° to 7f?° P),

regardless of nutrient

solution concentration#
A l t h o u g h root temperature h a d a pro nou nce d effect on
the total growth of the aerial portions of the plant,

the

organic composition of the foliage was not significantly
altered by differences in root temperature.

However,

there

were significant changes in the organic composition of the
roots w i t h root temperature.

Temperature

effects upon

organic components appeared to be more or less l oca liz ed
w i t h i n the plant part subjected to differential

temperature

treatment 0
Root temperature appeared to have very little,

if any,

appreciable effect on the nutrient-element composition of
the aerial portio ns of the plant.

Total ash of the roots

was subject to greater influence from root temperature
differences than was the foliage.
The total

concentration of salts in the nutrient solu­

tion h a d no appreciable affect on the percentage of crude
fiber and ether-extractable materials, but influenced the
percentage of nitrogenous and metabolizable carbohydrate
(N-free extract)

components in both the leaf and root tissue.

A l f r e d N, Roberts

The c o n c e nt rat ion of salts in the nutrient solution h a d a
ma r k e d effect on b o t h the total ash content and several
of its components in root and leaf tissues*
A significant negative correlation was found to exist
b et w e e n the m eta b o l i z a b l e carbohydrate
nitrogenous

(protein)

of the strawberry,

(N-free extract)

and

fractions in the roots and foliage

A significant negative correlation was

found also to exist b e t w e e n the content of ash and these
me tabolizable carbohydrate fractions in the roots and
foliage.

The same wa s true for these carbohydrate materials

and the ash component,

potassiums,

The possible influence of root temperature and "luxury"
absorption of nutrient elements on the efficient utilization
of organic fractions and efficiency in dry i</eight p r o ­
duction was considered*

ACKNOWLEDGEMENT
The author expresses his
Dr So A. L. Kenworthy,
professor)

sincere a pp r e c i a t i o n to

H. B • Tuk ey and E. J. Kr a u s

(Visiting

of the De p a r t m e n t of H o r t i c u l t u r e for their

helpful suggestions and guidance in this inves tig ati on
and for their e diting of the ma n u s c r i p t *
Re c o g n iti on is g ive n Dr. E* J. Benne, M* R. A. Bac on
and their l a b o r a t o r y assistants of the Depart men t of

A gri cultural C h e m i s t r y for their va luable assistance in
making the chemical analyses*

The au t h o r also a ppr eci ate d

the assistance of Dr. D* P* W a t s o n and E l i z a b e t h C lum of
the Department of H o r t i c u l t u r e in cer tain anatomical studies
related to the problem*
The author also w ants to thank Dr. L. M. T u r k of the
Soils Department and Dr. W.

B. Drew of the Department of

Botany and plant Pat ho l o g y for serving on his guidance
committee «

TABLE OP CONTENTS
Page
INTRODUCTION . • . . . .
REVIEW OF THE LITERATURE

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

3

Physiology of the S t r a w b e r r y ............................

3

Temperature as a Factor in G-rox'ith Processes

• • • «

14-

Temperature as a F actor in Root Growth and
Composition

10

Temperature as a Factor In Shoot Growth and
Composition
...........................
STATEMENT OF THE PROBLEM
]'LiilTIiODS C 0 0 0 0 . .
Equipment
PlantSe

13

» . . • • • • • •

16

0 * ® . # . * ® * 0 * * * * * * ®

lb

e . . c * .

lb

o e c o o . o o . . * * . *

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

19

Atmospheric C o n d i t i o n s # ...........................

19

Nutrient Solutionso

. . . «

20

. • • • • • • * • * . . • • .

23

• • • • • • •

Summary of Treatments
Growth Measurements

. * • « . .

Composition Analyses*

*

Growth Measurements

o * ........... . . •

. o . o . . « . * . < > o . . .

Statistical Analyses*
EXPERIMENTAL RESULTS

.........

.......................
..............* ................

• * • • • . . . . * . . • • • •

Plant Composition 0 0 . « o < i . o o . « .............
Correlations,
DISCUSSION

o . * . * * *

* * . . . .

2lf.
2 I4.

26
28
28
38

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

37

* .............................

63

Root Temperature in Relation to G-roxrth and
Development

63

TABLE OF C O N T E N T S

CONT.
Page

Co ncentration of N u t r i e n t S o l u t i o n in Rel ati on
to Growth and D e v e l o p m e n t . . . . . . . . . . . .

68

Root Temperature in R e l a t i o n to Plant
C o m p o s i t i o n ...................

69

Concentration of the N u t r i e n t S o l u t i o n in
Relation to Plant C o m p o s i t i o n , 0 . . . « • • • < >

72

Relation of C o m p o s i t i o n to G rowth
SUMMARY,

.

e o .

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

7^
79

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

LITERATURE CI TE D
'VPPENDIX.

. . . . . . . .

. .

82
a

89

L I S T OP TABLES
Table
I

II

III

IV

V

VI

VTI

VIII

IX

X

Page
Effects of root t e m p e r a t u r e and c o n c e nt rat ion
of nut rie nt sol u t i o n on dry w e i g h t a c c u m u ­
la tio n in R o b i n s o n s t r a wb err y . . . . . o o o o

30

Effects of root temper atu re a n d c o n c e ntr ati on
of n utr ien t sol uti on on the n u m b e r of leaves
and runners p r o d u c e d by R o b i n s o n strawbe rry
.......... » « * • • • •
plants, • • < > • * • • •

35

Effect of root t e m p e r a t u r e and c o n c e n t r a t i o n
of nut r i e n t sol u t i o n on pe t i o l e l e n g t h of
Ro binson s t r a w b e r r y leaves, , , , , , , , , , ,

37

Effect of root t e m p e rat ure and c o n c e n t r a t i o n
of nut rient sol u t i o n on the to p-root ratio
of Ro bi n s o n strawberry,
..............

39

Effect of root temperature on the organic
composi tio n of the roots a n d leaves of
R o b i n s o n str awb e r r y plants. • • < > • • • • • • 0

ij.0

Effect of c o n c e n t r a t i o n of n u t r i e n t solution
on the organic c o m p o s i t i o n of the roots
and l eaves of R o b i n s o n s tra wbe rry • 0 o » . • •

1+6

Effects of root te mpe rat ure on the n u t r i e n t element c o m p o s iti on of the roots a n d leaves
of R o b i n s o n str awb err y pl ant s • • « « » , « « •

1+8

Effects of the c o n c e n t r a t i o n of the nu tri ent
solution on the n u t r i e n t - e l e m e n t com pos iti on
of the roots and leaves of R o b i n s o n straw­
b e r r y p l a n t s .....................

1+9

Effects of root temperature a nd c o n c e n t r a t i o n
of the n utr i e n t s olu tion on the pe rce nta ge
dry w e i g h t of ce r t a i n organic components in
the leaves and roots of R o b i n s o n strawberry
plants,
< > • . « « , ,
. 0 , •

90

Effects of root te m p e r a t u r e and concentr ati on
of the n utr i e n t s olution on the percentage
dry w eig ht of total ash and certain ash
components in the leaves and roots of
Ro bin son str awb err y plants, , . o , « o o , , «

92

L I S T O F FI GURES
Figure
1
2

3

If

5

6

7

9

9

10

11

Page
C onstruction and arrang emen t of temperature
control tanks • .......... • • • . . . . . . . o

17

Effects cf r oot temperat ure and con cen tra tio n
of nutriei c so lut ion on growth of R o b i n s o n
strawberry plants •
. . . a

29

Effects of root temperature and con c e n t r a t i o n
of the n utr ien t sol u t i o n on total dry w eight
ac cum ula tio n in plants of R o b i n s o n strawberry

.

31

Effects of root te m p e r a t u r e and con c e n t r a t i o n
of the n u t r i e n t solut ion on dry w e i g h t
ac c u m u l a t i o n in leaves and roots of R o b i n s o n
.................................
strawberry.

33

Effects of root tempera ture and c o n c e n t r a t i o n
of the nu tri ent solution on the p r o t e i n con ­
tent of the roots and 3.eaves of the R obi n s o n
strawberry.
• • • . • • « .

Lp.

Effects of root temperature and c o n c e ntr ati on
of the n utr i e n t solution on the crude fiber
content of the roots and leaves of the
R o b i n s o n s t r a w b e r r y ..............................

Lf2

Effects of root temperature and c onc ent rat ion
of the nu tri ent solution on the content of
ether-e xtr act abl e m a t e r i a l s in the roots
and leaves of the R o b i n s o n strawberry • . 0 • •

i|3

Effects of root temperature and c onc ent rat ion
of the nutrient solution on content of
n i t r o g en- fre e extract in the roots and
leaves of the R o b i n s o n strawberry

J-jlj-

Effects of root temperature and c o n c e n tra tio n
of the nu trient s olution on the ash content
of the roots a nd leaves of the Robinson
s t r aw b e r ry s . o e . o o o o o . . .
. . . . . .

^0

Effects of root temperature and concen tra tio n
of the nut rie nt solution on the p o t a s s i u m
content of the roots and leaves of the
R o b i n s o n strawberry . o . o . . o . e * . o . .

5>1

Effects of root t emperature and concentration
of the nut rie nt solution on the phosphorus
content of the roots and leaves of the
R o b i n s o n strawberry . 0 <, • . • • • • • • » • •

5>2

L I S T OP F I G U R E S

CONTo

Figure
12

Page
Effects of root t e m p e r a t u r e and. c o n c e n t r a t i o n
of the nut r i e n t s olu t i o n on the calcium
content of the roots and leaves of the
R obi n s o n st r a w b e r r y o . o . o o .

53

13

Effects of root t e m p e r a t u r e and c o n c e n tra tio n
of the nut r i e n t s o l u t i o n on the m a n g a n e s e
content of the roots and leaves of the
R o b i n s o n s tra wbe rry . ............................ 54-

lLj.

Rel ationship b e t w e e n p e r c e n t a g e of n i t r o g e n free extract a n d p e r c e n t a g e of p r o t e i n on
a dry vreight b asis in the r o o t s of Rob ins on
strai-fberry plants sub je c t e d to v ari o u s root
temperatures and n u t r i e n t c o n c e n t r a t i o n s , a o ,

58

Relationship b e t w e e n percen tag e of ni trogenfree e xtract and pe rce n t a g e of p r o t e i n on
a dry w e i g h t b a s i s in the l eaves of R o b i n ­
son st raw ber ry plants sub jec ted to various
root t emp era tur es and nu trient co nce ntr ati ons o

59

Relati ons hip b e t w e e n p e r c ent age of n itr ogenfree extract and p e r c e n t a g e of total ash on
a dry w eight basis In the roots of R o b i n s o n
strawbe rry plants s u b j e c t e d to various root
tempera tur es and nu tri ent concentrations*
«« •

60

Re lationship b et w e e n p e r c e n t a g e of n i t r o g e n free extract and pe r c e n t a g e of total ash on
a dry w e i g h t basis in the leaves of R o b i n s o n
strawberry plants subjected to va rious root
temperatures and
nu trient concentrations, • . «

6l

15

16

17

18

Relatio nsh ip b e t w e e n p erc enta ge of nitrogenfree extract and p e r c e n t a g e of p o t a s s i u m on
a dry w e i g h t basis in the roots of R o b i n s o n
strawbe rry plants sub ject ed to various root
temperatures and
nut rie nt concentrations. . • • 63

19

Re lationship b e t w e e n p e r c ent age of nitrogenfree extract and p e r c ent age of p o t a s s i u m on
a dry w e i g h t basis in the leaves of R o b i n s o n
strawbe rry plants s u b j ect ed to va rio us root
te mperatures and n utrient concentrations 0 • , • 6 I4.

INTRODUCTION
Studies of the effect of t emp era tur e on the g r o w t h and
development of the

strawber ry plant hav e b e e n c o n f i n e d to

the relationship of a t m o sp her ic temperat ure s to pho top eri odi c
responses©

These o b s e r v ati ons have b e e n c o n c e r n e d pri marily

with the gr o w t h of aerial parts of the plant*
other crops,

As w i t h mo st

c o m p a r a t i v e l y li ttl e a t t e n t i o n has b e e n giv en

to evaluating the Importance of root t e m p e rat ure as a factor
In the growth and phasic dev e l o p m e n t

of the st raw ber ry plant*

There is a g r o w i n g a p p r e c i a t i o n am o n g plant scientists,
particularly those w h o deal in the a p p l i e d sciences,

of the

need for mor e systemat ic studies of the ecological factors,
both i ndi vid ual ly a n d collectively, w h i c h b r i n g about phasic
development in p lan t g row th along w i t h the a c c o m p a n y i n g
changes in plant

structure

and composition.

The soil

scientist is i n t e r e s t e d in m o r e f u l l y u n d e r s t a n d i n g the
Importance of the p h y s i c a l p r o p e r t i e s of soils In d e t e r min ing
the growth and c o m p o s iti on of plants©
methods of app roa ch receive

U n t i l these two

sufficient si multaneous

study,

it ma y be impossib le to a c c u r a t e l y correlate e ith er soil or
plant analyses w i t h gr owt h r esp onses of plants to various
environmental conditions©
In order to acc omp l i s h the objectives d esi red by the
plant and soil scientists,

a series of studies w o u l d be

2

necessary.

This series of s tudies sh o u l d involve con tro lle d

root temperatures

and nu t r i t i o n a l c ond iti ons as t hey influence

growth and phasic d e v e l o p m e n t of the p lan t in r e l a t i o n to
organic and ash composition.
parts of the plant sh oul d b e

B o t h the roots and aerial
c o n s i d e r e d i n such an e v a l u ­

ation of plant g r o w t h du rin g the several ph ase s of dev elo p­
ment.

The r e s u l t s of suoh a series of studies

should f urn ish

information con ce rni ng the desirable t emp era tur e and
nutritional c o n d i t i o n s that w o u l d p rom o t e the m o s t efficient
utilization of the pro duc ts of p h o t o s y n t h e s i s

in growth

and pr odu cti on of the plant u n d e r a g i v e n set of e n v i r o n ­
mental c o n d i t i o n s c
The objective of this initial

i n v e s t i g a t i o n was

limited to the e x p l o r a t i o n of the p o s s i b i l i t y of c o r r e ­
lating growth r esp o n s e of the strawberry,

as i n f l u e n c e d

by root t emp era tur es a nd c o n c e n t r a t i o n of the n u t r i e n t
solution, w i t h organic and ash composition.

The m e t h o d s

and results o b t a i n e d c o u l d then be u s e d in an e x p a n d i n g
program of e v a l u a t i n g the rel a t i o n s h i p of e col ogi cal factors
to plant growth and composition.

R E V I E W OF THE L I T E R A T U R E
P h y s i o l o g y of the S t r a w b e r r y
Gardner (1923)

and M a n n (1927)

o b s e r v e d that the

strawberry plant b e h a v e s like a biennial,

in that it stores

large quantities of n i t r o g e n a n d c a r b o h y d r a t e s in the summer
and fall for use i n p r o d u c t i o n of fol iage and fruit the
following spring*

Long

(1935)

e s t a b l i s h e d the fact that

fruit p r o d u c t i o n of the s t r a wb err y plant w a s determi ned
by the food reserves that accumulate during the growing
season and are m a d e
Whitehouse

available i n the springe

(1928)

su gge s t e d that the c a r b o hy dra te-

nitrogen status of the pl ant m i g h t be an i mpo rta nt fac tor
in fruitfulness of the s t r a w b e r r y plant*

The importance of

an efficient leaf surface i n f a c i l i t a t i n g the ac cu m u l a t i o n
of the products of p h o t o s y n t h e s i s a n d c omp ounds de rived
largely from t h e m for ad eq u a t e f r u i t - b u d d iff ere nti ati on
and fruiting the f o l l o w i n g sp r i n g was e s t a b l i s h e d b y Sproat
and Darrow,

G* M*

(1935)

The work of Greve

a n d M o r r o w a n d Darrow,

(1938)

G. M,

(1939)*

showed that fl owe r - b u d

differentiation in the st raw b e r r y w a s di re c t l y as soc iat ed
with the p h o t o p e r i o d u n d e r which

the plant w a s grown*

photoperiod in turn i n f l u e n c e d the chemical
the plant a nd Greve c o n c l u d e d that

c/lT

The

composition of

relations we re p a r ­

ticularly a ffe c t e d a n d thus fl owe r-b ud fo rmation w a s do-

pendent up on a n u t r i t i o n a l
Darrow,

G. M®

(1936),

Hartmann (1947)*

con dit ion w i t h i n the plant®

Darrow,

G. M®

and W a l d o

(1934)

and

showed that a r e d u c t i o n in a t m o s ph eri c

temperature m a y be as I m p o rta nt i n i n d u c i n g f low er formation
in the strawberry as a short ph oto per iod ®

They concluded

that at low atmospheric t emp e r a t u r e s flower buds m a y form

in the strawberry u n d e r l o n g p h o t o p e r i o d s «
Temperature as a F a c t o r in Gro wth Processes
Richards, H a g a n an d M c C a l l a

(195?2) have m a d e a co m p r e ­

hensive review of this subject®
Weiss

(1949)

c all ed a t t e n t i o n to the d i f f i c u l t y of

studying the influence of environmental factors on plant
development be cause of the complex nature of g row th processes®
However, he c o n s i d e r e d that the final

result of g r o w t h can

usually bo m e a s u r e d as an Increase I n dry w e i g h t

and v e r y

often in volume®
Through effects on phy sic al and chemical reactions,
temperature controls num e r o u s p h y s i ol ogi cal processes®

Xt

was outside the scope of this p a p e r to discuss the l i t e r ­
ature available on all these processes,

but since some of

these physiological pro ce s s e s h a d a direct b e a r i n g on the
results obtained fro m m a n i p u l a t i o n s of root temperatures
they have be en co n s i d e r e d mor e fully®
Absorption of W a t e r
Kr a m e r (1949) has rev i e w e d the literature on the

5

subject of the in flu enc e of roo t t e m p e r a t u r e on w a t e r
absorption.

It h a s b e e n d e m o n s t r a t e d b y B r o w n

Bermuda grass a n d b y B a i l e y a n d Jones
vated blueberries t h a t l o w

(1939) w i t h

(19J+1) w i t h c u l t i ­

soil t e m p e r a t u r e d e c r e a s e d the

ability of the pla nt to absorb w a t e r a n d res ult ed in w i l t i n g
of the plants w h e n t r a n s p i r a t i o n w a s

Doring (193!?) t Rou schal

s u f f i c i e n t l y high®

and K r a m e r

(1935)

(19i+2)

showed

that the rate of w a t e r a b s o r p t i o n by w a r m w e a t h e r crops
or plants native

to w a r m cl ima tes was m o r e

closely c o r r e ­

lated w i t h soil t e m p e r a t u r e t h a n are p l a n t s ada p t e d to
cooler seasons or climate®
Clements and M a r t i n

(1934-)

Ellis

and Sw ane y

(19il7)

found that w h i l e w a t e r a b s o r p t i o n appe ared to increase
with temperature up to a c e r t a i n point,

a level w a s r e a c h e d

where further i ncr eas es in t e m p e r a t u r e r e s u l t e d in a le s s e r
rate or quantity of w a t e r absorption.

Kramer

(19^4-9) r e v i e w ­

ed and d isc ussed the p o s s i b l e ex p l a n a t i o n s for the. r e l a t i o n ­
ship of root temper atu re

to w a t e r absorption,

but this

literature was b e y o n d the scope of this invest iga tio n®
Absorption of thitrients
W h i l e the li ter a t u r e

c o n t a i n e d m a n y data ind ica tin g

that nutrient intake w a s less

at low temperatures, H a g a n

(1952) was of the opi n i o n that it was very di ffi cul t If
not Impossible to separate the effects of low temperature
on the ab so rp t i o n process f r o m those on tra ns l o c a t i o n and
assimilation®
K r a m e r and Cur rie r (1950)

rev i e w e d the concept of

6
permeability and its r e l a t i o n to w a t e r a n d mi n e r a l
Hoagland and B r o y e r

(1936)

absorption*

sh o w e d that the a c c u m u l a t i o n of

mitrient salts b y p l a n t s w a s n ot m e r e l y a m a t t e r of cell
permeability b ut that energy e xchange w a s n e c e s s a r y for the
root to absorb n u t r i e n t s against

a c o n c e n t r a t i o n gradient*

They observed that w i t h i n c e r t a i n t e m p e r atu re ranges
C) there w e r e h i g h t e m p e r a t u r e c o e f f ic ien ts

(6 ° -

(2,f? - 5>*0)

for salt accumulation#
C o n c e n t r a t i o n of the n u t r i e n t s o l u t i o n :
Broyer (1936)

H o a g l a n d and

d e m o n s t r a t e d the im por tan ce of the co n c e n ­

tration of the external so lut ion in d e t e r m ini ng the ash
composition of the plant.

T h e y e x p r e s s e d this r e l a t ion shi p

of concentration i n the cell sap to that in the sol ution as
accumulation ratios.

These values w e r e d epe n d e n t u p o n the

concentration of the culture

solution*

Hoagland

(191+14-)

called att ention to the f a c t that the amount of selective
absorption of ions b y pla nts v a r i e d w i t h temperature*
Wanner (19l+8a, 19i4-8b) studied the inf lue nce of t e m p e ra tur e
on anion and c a t i o n a b s o r p t i o n and also l i n k e d such
absorption to the c o n c e n t r a t i o n of the external solution*
He found the t emperature co eff ici ent s for a b s o r p t i o n of
anions wer e h i g h e r t h a n those fo r a b s o r p t i o n of cations an d
that these temperat ure coe f f i c i e n t s w ere low er w i t h h i g h e r
external concentrations.

He

suggest ed that salt a b s o r p t i o n

from hi ghe r concent rat ion s w a s less dependent u p o n te mpe r­
ature than from l o w e r con centrations b ec a u s e les s energy
was requi red*

7

Since,

salt a b s o r p t i o n w a s

dependent u p o n the m e t a ­

bolic activity of the roots, H o a g l a n d and B r o y e r

(1936)

emphasized that coeffic ie nts for salt a c c u m u l a t i o n in cre a s e d
indirectly.

Kramer

(1914-9), and H a b e r

(1914-3) p o i n t e d out

the importance of the p h y s i c a l factors i n v o l v e d in salt
accumulation,

such as v i s c o s i t y and ion m obi lity.

(1914-6 ) and J a c o b s o n an d O v e r s t r e e t

Jacobson

(1914-7) f oun d that

certain ions w e r e a b s o r b e d at t e m p e r a t u r e s as low as 0° C*
Ha g a n

(1932)

after r e v i e w i n g the subject c o n c l u d e d

that there was n o t sufficient evi dence a vai l a b l e to prove
that a reduced rate of nu tri ent a b s o r p t i o n w a s r esponsible
for the slow growth of p lan ts at low root temperatures*
Ni tro gen s t a t u s ;

Nig h t i n g a l e

(1933*

that nitrate w a s a b s o r b e d b y the tomato,

1933)

observed

apple and p e a c h

at temperatures n e a r the m i n i m u m for growth.

He and Blake

(19314-sl, 1 9 3 l-!h) su gge ste d that n i t r o g e n uptake b y apple and
peach was greater at h i g h e r t e m p e r a t u r e s e

Darrow,

R. A*

(1939) w o r k i n g w i t h b l u e g r a s s w a s in agreement w i t h this
viewpoint*

These studies w i t h various crops i n d i c a t e d that

low temperatures did not g r e a t l y affect the a bso rp t i o n of
nitrate but did seriously limit the a b i l i t y of the roots to
metabolize this nitrate to organic ni tro gen ous m a t e r i a l s
necessary for growth*
Nightingale a nd Blake

(19314-0-* 1931-4-b) found evidence in

peaches that the tr ans l o c a t i o n of these e lab or a t e d n i t r o g e ­
nous ma terials to o t h e r parts of the plant wa s co ntr oll ed
to considerable extent b y temperature.

I n greenhouse

8

studies w i t h apple trees*

Batjer,

conclusions of N i g h t i n g a l e
also reported by A l d r i c h

ejc si

a n d Blake,

(1931)

(19i+3) v e r i f i e d the
S i m i l a r res ult s we re

and by Smith

(1933)*

Trailslocation of O r g a n i c M a t e r i a l s
Went, _et al

(19M4-b > 1914-6 > 19^4-9) f o u n d that the amount

of sugar t r a n s l o c a t e d i n the tomato d e c r e a s e d as the t e m p e r ­
ature was i n c r e a s e d f r o m 8° to 26° C*
the opinion of C urtis

(1929)

This w a s

and Cur tis

and H e r t y

that there w a s a p o s i t i v e r a t h e r t h a n n e g a t i v e
coefficient in t ran s l o c a t i o n .
grasses and H e w i t t and C urti3

Brown

con trary to
(1933)

temperat ure

(1939) w o r k i n g w i t h

(19l-}-8) w i t h b e a n p l a n t s

f ound

the same n ega t i v e t e m p e r a t u r e c o e f f i c i e n t f o r tr ans loc ati on,
Batjer,

ejb al

(1939)

o b t a i n e d s i m i l a r r e s u l t s w i t h apple

trees,
Respiration of O r g a n i c M a t e r i a l s
Most p h y s i o l o g i c a l
ature coefficient

texts are a g r e e d that the t e m p e r ­

(Q^C))

**©spiration w i l l average

between 2,0 and 2,5 in a t e m p e r a t u r e range of 0° to 35° Co
Gerhart

(19ij-0) st a t e d that the t e m p e rat ure c oe f f i c i e n t for

respiration in the fruit of the str awb err y w a s 2 ,5 for
temperatures b e l o w 25° C •

Brierley and Landon

(1937)

found that r e s p i r a t i o n of the s t r a w b e r r y plant c o u l d be
measured e v e n w h e n the pl a n t s w e r e
;ui.d plant activiti es

at a l o w ebb.

in a f r o z e n co ndi t i o n
T h e y f o u n d t hat in

general the r e s p i r a t o r y rate at 0° C for the s t r a w b e r r y
was hi g h e r than i n v e s t i g a t o r s h a d fo und for w o o d y plants.

9

The work of H e w i t t and Curtis

(194-8) showed i n c r e a s i n g

rates of r e s p i r a t i o n for mos t p lants w i t h i n c r e a s i n g t e m p e r ­
atures.
The d epl e t i o n of o rganic r e s e r v e s in the p lan t as a
result of h i g h e r r e s p i r a t i o n and gr owt h rates w i t h h i g h e r
temperatures h a s b e e n d e m o n s t r a t e d by several investigators*
Benedict

(1950) w o r k i n g w i t h q u a y u l e p lants f oun d the

percentage of free sugars,

levulins

roots dropped r a p i d l y as the soil
to 65° F.

N i g h t ing ale

and Blake

with fruit trees and D e c k e r

and i n u l i n in the

te mperature w a s i n c r e a s e d
(1934a > 1934b) w o r k i n g

(1944) w i t h pine f oun d that

carbohydrate reserves d e c r e a s e d w i t h i n c r e a s i n g temperature*
Brown (1939)

and S u l l i v a n and Sprague

same condition in forage grasses*

(1949)

Weinman

o b s e r v e d the

(1948)

reviewed

the effects of temperature on the re serve substa nce s in
grasses and con cl u d e d that u n d e r n orma l gro w i n g conditio ns
the carbohydrate content of these p l a n t s dec re a s e d as
temperature increased*
Assimilation and Gr owth
Hagan (1952)

in his r e v i e w of plant g rowth processes

in relation to temperature c alled a t t e n t i o n to the c o m p l e x ­
ity and lack of kno wle dge

co nce rni ng the m e c h a n i s m wh ere by

growth results f r o m the a s s i m i l a t i o n of basic materi als «
Ho cited the reviews of B a r r o n (1949)
(1950)

as support for this conclusion.

and K r a m e r and Cur rier
However,

of respiratory energy tr ans f e r studies by B o n n e r
Van Niel

(1949)

the results
(1949)

and

e m p h a s i z e d the role of me tab oli c pr ocesses

10

In plant g r o w t h a n d th e s e i n t u r n h a v e b e e n s h o w n to be
temperature se n s i t i v e *
Wilson

(191+9) p o i n t e d out that e x p r e s s i o n s p e r t a i n i n g

to the r e l a t i o n s h i p b e t w e e n t e m p e r a t u r e
ature c o e f f i c i e n t a n d V a n H o f f ’s Law)
value in p r e d i c t i n g t h e

w e r e of d o u b t f u l

MacDougal

(1920)

i m p o s s i b l e m a t h e m a t i c a l l y to l i n k v a r i ­

ations of g r o w t h w i t h t e m p e r a t u r e v a r i a t i o n s ,

because

growth w a s m o d i f i e d b y a n y one of m a n y m e c h a n i s m s
on p r e v a i l i n g t e m p e r a t u r e ,
and W e i s s

(19^9)

(temper­

i n f l u e n c e of t e m p e r a t u r e i n r e l a t i o n

to such c o m p l e x p h e n o m e n a as gr owth*
stated th at it w a s

an d g r o w t h

also

Hagan

(1952), W o n t

dependent

(19^-i-i-a, 19i|kb)

s u p p o r t e d this e a r l i e r l i n e of rea son i n g .

Te m p e r a t u r e as a F a c t o r i n R o o t G r o w t h a n d C o m p o s i t i o n
The l i t e r a t u r e on t he

s u b j e c t i n d i c a t e d t h a t growth,

development a n d c o m p o s i t i o n o f t he r o o t w e r e
directly by soil t e m p e r a t u r e

influenced

and indirectly by

the s u p p l y

of c a r b o h y d r a t e s to t he r o o t s t r a n s l o c a t e d to t h e m f r o m the
p h oto syn the tic p a r t s

of t h e p l a n t .

While

dat a o n the e f f e c t

of root t e m p e r a t u r e o n the groitfth a n d d e v e l o p m e n t of the
strawberry p l a n t

were n o t availabl e,

considerable inf o r ­

m a tio n was a v a i l a b l e f o r o t h e r c rop s w h i c h
in e v a l u a t i n g the r e s p o n s e s

s h o u l d be u s e f u l

that m i g h t o c c u r i n the

case

of the s t r a w b e r r y *
Stuckey

(1 9 I4I )

and Brown

(19^4-3) f o u n d In g e n e r a l

that

root gr owth In f o r a g e g r a s s e s w a s g r e a t e r d u r i n g the e a r l y
spring and fall w h e n t e m p e r a t u r e s were l o w e r a n d that there

11

was little or no development of the roots during the heat
of summer.

Darrow,

R. A.

(1939)

verified these observations

under controlled greenhouse air temperatures.

He attributed

the low root weights o b t a i n e d at hi g h e r temperatures to a
lack of available carbohydrates

high respiration.

Stuckey

associated w i t h excessively

(19i|-2) investigating the root

growth of several grasses in nutrient solutions under con­
trolled temperatures f o u n d similar trends in root growth
with temperatureo
Brenchley and Singh (1922) n o t e d the importance of
root temperatures in determining the tolerance of pea
seedlings to h igh air temperatures.
Tisdale

(1921)

Jones, P. R. and

called attention to the influence of light

intensity and plant age on plant responses to 3oil temper­
ature .
I n the case of cereal crops, D ickson

(1923) obser ved

that spring and w i n t e r wheat made their greatest root
growth at relatively low soil temperatures.

Wort

(19l{-0)

found the dry weights of roots of Marquis wheat were less
as soil temperatures increased u n d e r the conditions of his
experiments.

Di cks on (1923)

determined that corn roots

irrespective of the age of the plant made their greatest
growth at h i g h e r soil temperatures than that for most crops
studied.
The research of Jones, P. R. and Tisdale

(1921) has

been interpreted by Earley and Cartter ( 1 9 ^ )

as showing

come interesting relationships of light to the influence of

12

soil temperature o n root developm ent i n the soybean.
observed that,

in a general way,

increasing temperature

They

root g r o w t h i ncr eas ed wit h

from 2° to 25° C, but light intensity

determined the amount of root growth response relative to
increases in root temperature*

U n d e r low light conditions,

root growth was affected to a le s s e r degree b y soil te m p e r ­
ature «

The investigations of Joh n s o n and Har tma n
Arndt (1932), Tavernetti

(19^4-)

(1919),

Pierce and W o o d (1 9 I4.6 )

showed close correlations be tween soil temperature and
root development fo r numerous other agronomic crops.

How­

ever, the results o bta ine d in m a n y of these studies w ere
conditioned by environmental

factors other than soil t e m p e r ­

ature c,
Growth responses of veg eta ble crops to soil temperatures
also vary w i t h species and environmental conditions,
holder (1920), Richards

(1921), Bushnell

(1925)

B urk ­

and H o a g l a n d

(19^-|1|) have r epo r t e d the response of some of these crops to
soil temperatures.
The effect of temperature on the gr owt h of apple roots
was studied b y Collison (1935), who found some root growth
at temperatures near the freezing point*

Nightingale

(193il,

1935) made extensive studies of the effects of temperature
on the roots of apple trees.

He observed that the presence

or absence of a well-developed,

fibrous root system i nfl u­

enced growth of the roots at low temperatures.

Batjer,

e_b

al (1939) obtained similar results with dormant apple trees.

13

Rogers

(1939)

b y m e a n s o r o b s e r v a t i o n t r e n c h e s n o t e d that

aople trees i n an o r c h a r d d e v e l o p e d i n c r e a s i n g l y m o r e n e w

roots at soil t e m p e r a t u r e s f r o m 7° to 2 1° C*
(1914-3 ) m a d e

Proebsting

similar observations.

Woodruff and Woodruff

(19314-) w o r k i n g w i t h p e c a n s

and

Girton (1927) w i t h c i t r u s also r e p o r t e d close r e l a t i o n s h i p s
between t e m p e r a t u r e

and r o o t

Sh ank s a nd L a u r i e

growth in these

crops*

(1914-9) o b s e r v e d t h a t the f r e s h

weight of the roots of g r e e n h o u s e r o s e s w a s p r o p o r t i o n a t e l y
less as the t e m p e r a t u r e

of t h e r o o t s i n c r e a s e d *

The

appearance of the ro ots g r o w n at v a r i o u s t e m p e r a t u r e s
corresp ond ed c l o s e l y to t h o s e d e s c r i b e d b y N i g h t i n g a l e
for- apple*
The o n l y s t u d y to b e f o u n d in the l i t e r a t u r e
the i n f l u e n c e

of soil t e m p e r a t u r e

development w a s that of G r a y
c e r n e d w i t h the
atures on the

Temperat ure
Gannon

regarding

on s t r a w b e r r y root

(194-1) •

Thi s s t u d y w a s

con­

e f f e c t s of e x c e s s i v e l y h i g h r o o t t e m p e r ­

g r o w t h of s t r a w b e r r y roots*
as a F a c t o r i n Sh oot G r o w t h a n d C o m p o s i t i o n

(1 9 1 7 ) e a r l y r e c o g n i z e d that u n d e r u n f a v o r a b l e

atmospheric c o n d i t i o n s
maintaining favorable

shoot

growth could be increased by

root t e m p e r a t u r e s for growth*

The i n f l u e n c e of root t e m p e r a t u r e

o n the g r o w t h of the

aerial p o r t i o n s of fo r a g e c rop s has b e e n s t u d i e d b y Darrow,
H* A.

(1939),

Stuckey

(194-2), Jones,

and E a r l e y a n d Cartt-er (194-5) •

P. R* a n d T i s d a l e

Although,

(1921)

the t e m p e r a t u r e at

li+
which m a x i m u m d r y w e i g h t p r o d u c t i o n o c c u r r e d v a r i e d w i t h

snecies and variety,

there was a t e n d e n c y In all

cases

for top growth to be l e s s at b o t h e x c e s s i v e l y low or h i g h
temperatures «
D i c k s o n (1923)

and Wort

(191-1-0) o b s e r v e d that the

optimum root t e m p e r a t u r e for m a x i m u m top g r o w t h of w h e a t
was

lo wer for l a t e r s tag es of p l a n t g r o w t h t h a n for the

early stages d u r i n g p l u m u l e

d e v e l o pme nt*

Dickson

(1923)

found a s imi lar shift in o p t i m u m root t e m p e r a t u r e for
shoot g row th w i t h p h y s i o l o g i c a l

age of the c o m

p l a n t bu t

in the opp osite d i r e c t i o n to that o b s e r v e d for w h e a t an d
most o the r crops
Jones,

studied*

P. R. a n d T i s d a l e

(192:1) c a l l e d a t t e n t i o n to

the importance of inc i d e n t r a d i a t i o n In d e t e r m i n i n g the
response of s oyb ean xjla n ta to I n c r eas es i n soil t em p e r a t u r e *
The so-called o p t i m u m t e m p e r a t u r e I n c r e a s e d w i t h g re a t e r
light i n t e n s i t y 0

Gamp and W a l k e r

(1927)

also p o i n t e d out

the importance of o t h e r e n v i r o n m e n t a l f act o r s

In d e t e r m i n i n g

the res pon se of shoot gr owth of co t t o n to soil t e m p e r a t u r e ®
Nightingale

(1935),

Proebsting

(19^4-3) and Batjer, £ t al

(1939) o b s e r v e d the top gro wth of apple a n d p e a c h trees to
be closely c o r r e l a t e d w i t h the volume o f roots p r o d u c e d at
the d i f f ere nt te mpe r a t u r e s .

Halma

(1935)

and H a a s

(1936)

studied the g r o w t h of citrus at various soil te mperatures
and found c o n s i d e r a b l e

differ enc e

in response w i t h the various

species u s e d i n c o m m e r c i a l pr o d u c t i o n ®
Shanks a n d L a u r i e

(191-J-9) f o u n d the fresh a n d dry weight

15

of shoots of B e t t e r Times roses i n c r e a s e d d i r e c t l y w i t h
soil temperatures.
bop-root ratios.

H i g h r oot te m p e r a t u r e s f a v o r e d h i g h
The effects of soil te mpe rat ure on shoot

growth of Rubel b l u e b e r r i e s

s tud ied b y B a i l e y and Jones

(19 I4J.) fo llo wed a similar pattern.

I n bot h the above

studies h i g h root t e m p e r a t u r e s r e s u l t e d In tall upr igh t
plants,

as c o m p a r e d w i t h l o w sp rea din g plants

temperatures o

at low root

STATEMENT OP PROBLEM
The purpose of the f ollowing study was to explore the
possibility of corre lat ing the growth response of the straw­
berry plant to ce rtain ecological conditions,

namely,

root

temperature and concentration of the nu tri ent solution,
with its organic and min era l composition.

Also considered

was the relationship b e t w e e n certain of these organic and
mineral constituents an d their influence on the total p r o ­
duction of dry ma t t e r in the root and aerial portions of
the plant.

By this means,

an attempt w a s made to evaluate

the effects of b o t h root temperature and concentration of
the nutrient solution on the ac cum ula tio n of these organic
and ash constituents in the plant and their b e a r i n g on the
efficiency of dry weight production.

ME THO DS
Equipment
Root temperature control was obtained by means of a
series of temperature control tanks designed after those
described b y M e l l e n t h i n (1951)*
College

(Figure 1).

assembled at Mic hi g a n State

These tanks,

structed b y en closing 3 0 0 -gallon,

f o u r in number, were c on­
round-end stock tanks in

insulated plywood boxes, w h i c h were strongly reinforced to
support the weight of the w a t e r they were to contain,,

A

Figure 1

Construction and arrangement of temperature control tanks

A

- General view of tanks after completion and before plant
containers were added

B

- Close-up showing three of the plant containers in place.
Crocks in the background are being drained of excess
solution in a rack designed for this purpose

C

- Close-up showing one of the tanks with all plant
containers in place

17

18
three-quarter-inch ply woo d removable top on each tank had
twelve round holes,

each nine inches in diameter.

Through

each hole a two-gallon glazed crock could be plunged into
the temperature controlled w a t e r bath.

The top of the crocks

were at the level of the top of the tanks and supported by
wooden frames re s t i n g on the b ott om of each tank.

A n over­

flow pipe located near the b o t t o m of the box-enclosed tank
regulated the w a t e r level around, the crocks in the tank.
Each tank contained both a thermostatically controlled
lead heating cable and a refrigeration unit to control the
water temperature w i t h i n 2 ° F of the desired water temper­
ature,

Circulation of the w a t e r in the tank to assure even

distribution of temperature effects was accomplished by a
standard centrifugal pump of six-gallon-per-minute
The containers,

capacity.

two-gallon glazed crocks, were used to

hold the sand in w h i c h the plants were grown.
were commonly us ed as coffee urn liners.

Such crocks

These containers

were well suited to the purpose for whi ch they were used,
since they h a d a tapered base and a one-inch round hole in
the botton, w h i c h p ro vided complete drainage.

This drainage

was provided for and at the same time the water kept out of
the crocks by means of a No, 11 rubber stopper fitted with
a glass tube,
clamp.

a small piece of rubber tubing and a pinch

W h e n in the tank,

tube kept out the water.

the pinch clamp on the drainage
When solution was to be added

and the excess drained off, the crock was removed and placed
in racks mado for this purpose,

The pinch clamp was then

19
removed, the s o l u t i o n added,
replaced in the tank.

and after drainage,

the clamp

I n ord er to p revent the sand from

clogging the glass tub© inside the crock,

a f our - i n c h watch

lass was I n v e r t e d ov er the jnside opening.

This m e t h o d of

handling the crocks p r o v i d e d excellent drainage and aeration
throughout the time of the experiment.
tainers w e r e

Twelve

such c o n ­

ava ilable in each tank.

The plants in each

crock were e q u a l l y e x p o s e d to light,

air cir cul ati on and

other te m p e r a t u r e effects as shown b y record ing thermographs.
Plants
St raw b e r r y p l a n t s of the Ro bi n s o n variety,

that had

been stored t hr o u g h the winter, w e r e u s e d In these studies.
These r u n n e r pla nts w ere w a s h e d free of soil and all but
two leaves w e r e r e m o v e d from each.

The roots we re p runed

uniformly to two inches in length.

The plants wer e graded

into two w e i g h t classes - 6 + 1

gm and ij. + 1 gm«

from e ach group was p l a n t e d in each crock.

One plant

These plants

were typical of those u s e d i n commercial p l a n t i n g during
the spring,

aft er storage.

A l l b l o s s o m clusters we re

removed as soon as t h e y ap pea red In the crown to assure
additional un ifo rmi ty.

The fr uit ing phase was not con­

sidered In this study.
Atmospheric Conditio ns
A t m o s p h e r i c temperatures were m a i n t a i n e d b y manual
operation of the ventilators.

Night temperatures were

maintai ned b e t w e e n £0-60° F during the first m o n t h

(March 22

20

to April 22) and at 60-65° F during the final m o n t h (April
22 to Ma y 26)«

The ave rag e night temperat ure va r i e d less

than 5° d uring the p e r i o d of a week.

Day temperatures

varied more because of the constantly changing solar
radiation d u r i n g the t w o - mo nth s period.

Day temperatures

increased slowly from the ni ght temperatures me nti o n e d

to a m a x i m u m of 80° F du rin g the day (first month)

and to

a 100° F m a x i m u m (slightly h i g h e r on a few days) during the
last 30 days of the experiment.

However,

the daily average

approximated 70° F dur i n g the first m o n t h and 80° F during

the second month.
Solar r a d i a t i o n was variable during the fore part of
the 6 0 -day period,

but w a s u n i f o r m l y h i g h during the last

30 days of the experiment.

However,

light could not be

considered a l i m i t i n g f a c t o r in the growth of the straw­
berry plants©
hntrient Solutions
The n u t r i e n t solutions u s e d in these studies consisted
of three co ncentrations of Hoagland* s standard nutrient
solution No. 1.
full-Eoagland*s
Hoagland*s

The c onc e n t r a t i o n of these solutions were
(1.0); h a l f - H o a g l a n d » s

(0.1).

(0.5)% and one-tenth-

The dilute solutions were pr epa red by

adding the n e c e s s a r y amount of molar stock solutions to
distilled water.
throughout.

C h e m i c a l l y pure chemicals were used

The fo llo win g gives the amounts of the various

elements pr esent in such solutions:

21

0.5 H o a g l a n d

N

21 0 * 1 0 p p m

10 5*0 5 ppm

0,1 Hoa gla nd
21.01 ppm

P

30*98

15.49

3.10

K

23 4*6 0

11 7.30

23*46

Ga

200.40

100.20

20*04

Mg

48*64

24.32

4.86

B

0*50

0.25

0.05

Mn

0*50

0.25

0.05

Cu

0
0
0
ro

1*0 H o a g l a n d

0.01

0.002

Mo

0
•
0
H

Element

0.005

0.001

Pe

1*37

0*685

0.137

The pH of the H o a g l a n d ’ s solu-

Re action of solution:

tiona as p r e p a r e d for these experiments were 5 *0 , 5.0 and
5.4 for the 1 *0 , 0 * 5 and 0.1

solutions respectively.

At various times du r i n g the course of the experiment
the pH was d e t e r m i n e d after the s olution h a d be en left
standing for two days time

(the m a x i m u m time that the dilute

solution was e v e r left s t a n d i n g ) •
determinations we re 5o0,

The average of these

5*4 and 5.6 for the 1 *0 , 0*5 and

0*1 H o a g l a n d ’ s solutions respectively*
Since the difference b e t w e e n the pH of the fresh and
two-day old sol uti on and b e t w e e n the various concentrations
was never gre ate r than 0*6 it was not considered necessary
to adjust the pH of the solutions®
Renewal of s o l u t i o n s :

I n order to assure a minimum

amount of change in the relative concentration of the various
ions present in the s olu tio n as a result of differential

22
absorption of these ions b y the plants,

the solutions were

renewed o fte n a n d m o r e or less r egu l a r l y depen din g on we a t h e r
conditions.
intensity,

D u r i n g the fir st m o n t h of gr owt h w h e n light
air t emp era tur es

excessively high,
day.

and t r a n s pir ati on we re not

the so lutions w e r e ren e w e d every second

W h e n i n c r e a s i n g a tmospheric temper atu re and solar

radiation during the se c o n d m o n t h inc reased transpiration
and metabolic activity,
the two h i g h e r

p a r t i c u l a r l y w h e n associated w i t h

(65° and 75° F) root temperatures,

tions were r e n e w e d each day.

the s olu ­

Renewal of the solution was

accomplished b y the a ddi tio n of $00 ml of the nutrient
solution to each crock.

This amount w a s approximately

two to three times the volume w h i c h could be hel d b y the
sand.

At r e g u l a r intervals

(10-llj. days)

the sand was

leached w i t h d i s t i l l e d w a t e r to avoid the possible a c c u m u ­
lation of salts on the surface of the sand particles.
Fresh solution was t h e n added immediately.
I n or der to determine the efficiency of the above
practices in m a i n t a i n i n g u n i f o r m salt co ncentration about
the plant roots,

samples of leachate were taken perio dic all y

and tested w i t h a Solu-b rid ge for total salts present.
Fresh H o a g l a n d * s solutions of 1.0,

0.5 and 0.1 c o n c e n ­

tration gave Solu-bridge readings of 200, 110 and 214- mhos x
10""*^ respectively.

Lea ch a t e d isplaced from the sand b y

additions of fresh solution after two days gave Solu-bridge
readings of 2 0 0 , 1 0 0 and 20 mhos x 1 0 “ ^ res pectively from
the 1 .0 , 0 . 5 and 0.1 solutions in w h i c h the plants w ere

23
growing.

W h e n the l e a c h a t e w a s obt ain ed by displacement

with distilled w a t e r the r e a d i n g s dro p p e d to 1 7 0 , 8 £ and
_d
20 mhos x 1 0
Tor the same s o l u t i o n concentrations.
These
data indicate th at t h e r e w a s not appreciable change in the
salt con c e n t r a t i o n of the solutions before they were renewed,
A m e d i u m fine qu a r t z

sand u s e d in well footings was

used as the m e d i u m in w h i c h to grow the plants.

This

sand

was w ash ed r e p e a t e d l y w i t h tap wa t e r and then tr e a t e d for
four days w i t h a 1 0 p e r c e n t solut ion of commercial h y d r o ­
chloric acid.

This w a s f o l l o w e d by r e p e a t e d leachings with

tap water and f i n a l l y w i t h d i s t i l l e d water.

The pH of the

final w a s h w a t e r a v e r a g e d ap pro x i m a t e l y 6 .3 ®
Summary of T r e a t m e n t s
The s t r a w b e r r y pl ant s w h i c h h a d b e e n p r e p a r e d as
described were p l a n t e d i n the crocks on M a r c h 1 and pla ced
on a greenhouse b e n c h to become e s t a b lis hed before starting
the treatments.

E a c h crock of two plants w a s assigned

permanent treatment numbers w h i c h designa ted the root te m p e r ­
ature treatment and c o n c e ntr ati on of solution they were to
receive*

F r o m that time on,

they r e c e i v e d the respective

nutrient solutions as d e s i g n a t e d at intervals until they
we re well established.

O n April I4., they wer e p l a c e d in the

various temperature control tanks.
One each of the f o u r temperature
at )+50 , 55°,

65°,

and 7£° F.

each of these tanks.

tanks wa s m a i n t a i n e d

Twelve crocks were pla c e d in

E a c h group of four crocks in each tank

21+

received H o a g l a n d 1 3 n u t r i e n t sol u t i o n at concentrations of
1.0, 0*5 or 0.1.

T his p r o v i d e d four re plications of each

nutrient c o n c e n t r a t i o n at any g ive n root remperature.
each crock c o n t a i n e d two s tra wb e r r y plants,

Since

there were eight

plants for each c o m b i n a t i o n of nu tr i e n t level and root
temperature*

The pl a n t s w e r e m a i n t a i n e d as described in

the foregoing sections f r o m April l\. to M a y 28,

a p er i o d of

$L\. days, after w h i c h time the treatments w e r e terminated*
Growth M e a s u r e m e n t s
U p o n c o m p l e t i o n of the p e r i o d of treatment,

the entire

plant including the roo ts w a s re moved f r o m the crocks by
carefully w a s h i n g away the sand.

Af ter removal,

b o t h the

roots and tops w e r e w a s h e d in tap w a t e r and rinsed twice in
distilled water*

The n u m b e r of leaves and runners produced

by each set of two plants wer e recorded.
then divided into roots,

crowns,

The plants were

leaves,

runners for dry w e i g h t determinations.
measured for len g t h p r i o r to drying.

petioles,

and

The petioles were
Dr y weight de te r m i n ­

ations w e r e made b y ra p i d l y b r i n g i n g the plant parts to
constant w eig ht in a dehydra tor pr ov i d e d w i t h air circulation
and m a i n t a i n e d at a t emperature of 70° C.

The plant parts

were w e i g h e d se p a r a t e l y f o r each r e p l i c ati on on a torsion
balance e
Composition An aly ses
I n view of the small amount of total dry m att er of the
various plant parts,

the four replications were combined into

25
one sample for or gan ic a n d ash analysis.

Since q u a n t i t a ­

tive analyses of several o rg a n i c and ash fract ion s seemed
desirable,

the analyses w e r e l i m i t e d to the roots and leaves.

These parts,

r e p r e s e n t i n g the aerial and non-aerial portions

of the plants, w e r e c o n s i d e r e d as an index of the organic
and ash c o m p o s i t i o n of the v a r i ous ly treated plants as a
whole *
All samples in these tests w e r e pre p a r e d by grinding
the p rev iou sly dr ied plant ma ter ial
mesh s c r e e n ) .

in a W i l e y mill

(20

The g r o u n d samples were stored in glass

sample bottles.

P r i o r to a series of determinations,

the

samples were o v e n - d r i e d for 2l\. to ip8 hours at 100° C to
constant weighto
0 rganic a n a l 7fses:

The p r i m a r y interest in these studies

was in m e a s u r i n g the relative efficiency in dry weight pro ­
duction of the p h o t o s y n t h e t i c - r e s p i r a t o r y balance resulting
from exposure to the various root temperature and solution
concentration combinations.

A nal yse s for organic constit­

uents were th ere for e c onf i n e d to b r o a d groupings rather
than to a n u m b e r of fractions of individual substances.
The total amount of any one of these substances might vary
greatly de pen din g up on the
was taken.

stage of growth w h e n the sample

F o r this r e a s o n the analyses for organic com po­

sition c ons ist ed of a series of quantitative evaluations
used by the Departme nt of Agricultural Chemistry at M ich iga n
State College in assaying the nutritional qualities of feeds
for livestock.

Such an analysis provides the composition of

>

26

the dry m a t t e r in te rms of p r o t e i n (from K jel d a h l nitrogen),
crude fiber,

et her extract,

total ash and then b y difference,

nitrogen-free extract - c ons id e r e d as that p o r t i o n not
accounted for as protein,

crude fiber,

ether extract

and

total ash.
The quantit ati ve m e t h o d s f o r each of these tests are
modifications of those f o u n d in the Official Met hod s of
Analysis of the A s s o c i a t i o n of Official Agricultural Che m­
ists as u s e d b y the analytical l a b o r a t o r y of the Department
of Agricultural C h e m i s t r y at M i c h i g a n State College*
Ash a n a l y s e s :
of the roots

I n addition to a total ash determination

and leaves f r o m each treatment in the series,

analyses were also made

for several of the constituents

contained In the ash of the plant material.

Potassium

determinations w e r e made on the Perkins -El mer Flame P hot o­
meter and content of phosphorus,
ganese,

iron,

magnesium,

calcium, m a n ­

c opper and b o r o n wa s determi ned b y means of

spectrographic procedures.
Statistical An alysis
The data for growth measurements,
and composition (organic and ash), were
of variance.

dry weight produced
subjected to analysis

Since replicates were compos ite d for compo­

sition analysis,

a statistical evaluation of the interaction

between root temperature
was not possible.

and nutrient solution concentration

The compositing of samples also would

tend to increase the requirements for statistical differences

27

between m a i n effects
tion concentration)o

(root temperature and nut rie nt solu­
In

some instances trends i n the data

were indicated g r a p h i c a l l y that w ere not s upp orted by
statistical analysis*
Correlations b e t w e e n several organic and ash components
were tested for

significance.

These included those between

total ash and n i t r o g e n - f r e e extract;

p ota s s i u m and nitrogen-

free extract and b e t w e e n p r o t e i n and nitroge n-f ree extract*

E X P E R I M E N T A L RESULTS
G-rowth M e a s u r e m e n t s
Total Growth
Th© p h o t o gra phs i n Pigur© 2 show the total growth of
aerial parts b y r e p r es ent ati ve plants f r o m e a c h combination
of root tem per atu re and nu tr i e n t

solution*

The total dry w e i g h t of pl ant material,
aerial and root portions,

including all

p r o d u c e d b y each combination of

root t e m p e r a t u r e - n u t r i e n t con cen tra tio n conditions are
shown in Table I and Pigur© 3*

Th© total dry m a t t e r was

significantly greater w h e n the plants w ere grot*n in the
0c3 than in the 0*1 H o a g la nd* s

solution*

However,

1*0

Hoagland* s soluti on did not increase above that obtained
with a nut rient solution c onc ent rat ion of 0«5>*

The 0*5>

concentration of Hoagland* s solution w a s sufficient to
result in a m a x i m u m amount of growth as m e a s u r e d in terms
of dry w e i g h t pr oduction*
In general,

root temperature h a d the same effect on

total dry w e i g h t ac c u m u l a t i o n regardless of the concentra­
tion of the nu tri e n t

solution employed*

The trend was

toward inc rea s i n g dry w e i g h t as root temperatures increased
from i|5° P to 65° F*

There was no significant increase

between 65° F a nd ?£° P.

S i g n i f ican tly greater growth was

Figure 20 Effects of root temperature and concentration of nutrient
solution on growth of Robinson strawberry plants
—

Root temperature 75°; concentration of Hoagland’s solution
1.0, 0.^ and 0,1 (left to right)

B —

Root temperature 65°; concentration of Hoagland's solution
1.0, 0.5 and 0,1 (left to right)

—

Root temperature 55°; concentration of Hoagland*s solution
1*0, 0,5 and 0,1 (left to right)

D —

Root temperature 4.5°; concentration of Hoagland1s solution
1*0, 0,5 and 0,1 (left to right)

A

C

29

30
TABLE I
EFFECTS OF ROOT T E M P E R A T U R E A N D C ONC E N T R A T I O N OF NUTRIENT
SOLUTION ON DRY W E I G H T A C C U M U L A T I O N I N ROB INS ON STRAWBERRY

Plant
cart

Total
plant

Root
te mperature
(° P)

75
65
55

hS

Co n c e n tra tio n of Hoagland* s solution
1.0
0.5
0.1
Gras

Gras

Gms

>4-5*>4-8
39*66
30.89
19.26

J4.8 .oh
h3.1h
30.67
20.71

2 3.17
21. 9h
13*53
8.70

L.S.D.
Roots

75
65
55
h5

- %

6.00
6.01
6 «hO
6.65

L.S.D.
Leaves

75
65
55
'4-5

75
65
55
>1-5

75
65
55
h5

Crovrna

75
65
55
>l5

1 3 .3h
12.67
8.69
5.59

2.53
2.53
2.hh
2.18
LoS.D,

7oih
6.hi
a.02
2«3h

- 5% - 1.77 s 1 % =• 2.38

- %

21.80
17.78
ii«55
2.6 >4.
L.S.D.

>4-®09
h*53
ho 79
h » 11

- 5# = 1.35; 1% = I 081

3.50
3.11
2.01
i.i3

3*50
2.61}.
2. Oh
1 *h6
L.S.D.

Runners

6 .6 h
6.50
6.96
7.ho

11.67
10.71
8 oii.6
6 .3Il
L.S.D.

°otioles

= 7.98 5 1% = 10.69

=

0 .5 2 ; 1% =

1.85
i.h8
0.90
o,5h
0.70

21.50
18.20
10.67
h.70

8.30
7.6h
2.06
0.35

- 5% = 5.ih; 1 % = 6.88
3.07
2.66
2.3h
1.85

1.80
1.88
1.77
1.36

■*" 8% = 0.58; 1% = 0.78

W e i g h t s based, on h replications of 2 plants each
of 8 p l a n t s ) » Averages given are for 2 p l a n t s a

(total

31

TOTAL

DRY

WEIGHT

561—

co n c . 0 . 5

48—

O

Wei ght

in

tr-

Average

c onc-O. I

65

55

45

75

T emperature
Fi g u r e

3*

E f f e c t s of root
of the n u t r i e n t
a c c u m u l a t i o n in
(Using 1 »0, 0,5

rem p e r a t u r e a nd con c e n t r a t i o n
s o l u t i o n on total dr y weight
p lants of R o b i n s o n strawber ry
a nd 0,1 H o a g l a n d ’s solution).

32
obtained w i t h the 0 * 5 s o l u t i o n t h a n the 0*1 solution*
However,

so mewhat l e s s

gro wth w a s o b t a i n e d w i t h the l o0

solution th an the 0*5 solution*
The o nly e x c e p t i o n to this p a t t e r n w a s wi th plants
grown i n the w e a k

(0*1 Hoagland* s)

solution,

where as muc h

olant m a t e r i a l w a s p r o d u c e d at k5° F as at 55° F,
dry weight w a s

s i g n i f i c a n t l y g r e a t e r at 65° F than at 5£° F*

While not s t a t i s t i c a l l y significant,
solutions w a s for i n c r e a s e d total
with each t e n - d e g r e e

to 75° F*

alt hough

increase

the t r e n d in all three

dry we i g h t a c c u mul ati on

in root tempe rat ure f rom I4.5 0 F
temperat ure above 65° F did

I n c r e a s e s of root

not result in s i g n i f i c a n t l y more

dry m a t t e r reg ard les s of

the n u t r i e n t s o l u t i o n con cent rat ion *
Root D e v e l o p m e n t of the Plant
The effects of roo t t emp era tur e on the acc umulation of
dry weight of root,

as shown in Table I and Figure J4., were

noticea bly d i f f e r e n t f r o m those on the aerial po rtions of
the plant*

There were no significant differences in the

dry w e i g h t of ro ots of pl a n t s g r o w i n g at root t emperatures
from l\S° F to 75° F*

However,

at all s o l u t i o n c o n c e n t r a t i o n s

there was a definite t rend
to indicate that

increas ed as root te m p e r a t u r e decreased.

root w e i g h t

This w a s exactly

the o ppo s i t e of t h a t fo u n d for the aerial portions of the
plant *
Dr y w e i g h t

solution,

of roots w a s

greatest in the 0*5 H o a g l a n d 1 s

as were the aerial portions.

We igh t of roots was

not i n c r e a s e d w h e n the s olut ion co ncentration was raised to

33

DRY

WEIGHT

We i g h t

In

Grams

L eaves

Average

Roots

conc. 0 . 5

con c.

5 f—

45

65

55

75

Temperature

Fi gur e I*.*

E f f e c t s of roo t t em p e r a t u r e and c o n c e ntr ati on
of the n u t r i e n t s o l u t i o n o n dry w e i g h t accurau
l a t i o n in l e a v e s and roots of R o b i n s o n st raw ­
b e r r y (Using 1 j O, 0,5 and 0«1 H o a g l a n d ’s
solution)«

3k
1 o0 Hoagland* s.
Aerial portions of the Plant
Trie dry w e i g h t of the aerial portions of the plant,
which i n c l u d e

the petioles,

given in Table I .

leaves and runners,

The g r o w t h of these plant parts associ­

ated w i t h i n c r e a s e d root

concentration followed,

temperature
in general,

observed in total dry w eight.
3ame for leaves,

of leaves are
Leaves:

are also

pet iol es

and greater nutrient
the same trend as that

Since the response was the

snd runners,

only the dry weights

shown in Figure Ij..
I n c r e a s i n g the concentr ati on of the nutrient

solution from 0.1 to 0 05 i n c r ea sed slightly the number of
leaves but fu rth er increase in concentration h a d no effect
on leaf numbers

(Table II)*

Root temperature h a d even less

effect upon the n u m b e r of leaves.

Rai sin g the root temper­

ature from k5° F bo 5>5>° F slightly increased the number of
leaves in the two l o w e r concentrations of nutrient

solutions.

W h i l e root temperature and concentration of the nutrient
solution h a d little effect on n umb er of leaves,

there was

considerable effect on leaf size as exp ressed in the dry
weight of the leaves.

There was no significant difference

in the dry we igh t of leaves produced by the 1.0 and 0.^
Hoagland*s solutions,

but these were conside rab ly above

those p r o d u c e d in the 0.1 Hoagland*s
for total dry weight,

solution.

As found

leaf weight increased w i t h root

temoenature from li5° F bo a max imu m at 65° F w i t h no
further significant increase at 7^° F*

■
if

Uvd

TABLE II

EFFECTS OF ROOT TEMPERATURE AND CONCENTRATION OF NUTRIENT
SOLUTION ON THE NUMBER OF LEAVES AND RUNNERS PRODUCED BY
ROBINSON STRAWBERRY PLANTS
Root te mpe rat ure

(o F)

C o n c e n t r a t i o n of H o a g l a n d 1s solution

1.0

0.5

0.1

27.25
27.25
25.50
19.00

2k.,00

Leaves
75
65

55
kS

2 L u50
25.00
21)..00
2 0.75
L.SoD,

20.75
17 .00
11)-.00

- 5% = J+.69; l# = 6.28

Runners
75
65
55
k$

17.90
17.30
12.50
3.00

20.30
16 .30
12.80
5.80

13.30
10.50
5.00
0.50

L.S.D. - 5# = 2.90;. 1$ = 3.99
A v e r a g e s b a s e d on l\. r epl ica tio ns of 2 pl ant
of 8 p lants).
A v e r a g e s gi v e n are for 2 plants.

each (total

36
petioles *

The obs e r v a t i o n s m ade in re g a r d to dry

weights of the lea ves w e r e also m ani fes t in the dry weight
of the petioles

(Table X).

The responses to root temper­

ature and c o n c e n t r a t i o n of the nutrient solution were similar.
The effect of the treatme nts on petiole elongation

are shown in Table III*

Root temperature h a d a pr ono unc ed

effect on p e t i o l e length.

There wa s a general, trend toward

increased pe ti o l e l e n g t h w i t h h i g h e r root temperatures,
although pe ti o l e l e n g t h at 75° F w a s not significantly
greater than at 65° F 0

petiole l eng th was one of the more

obvious visible ex p r e s s i o n s of the influence of root temper­
atures upon the growth and development of the aerial portions
of the s t r a wbe rry plant.

This i ncr eased petiole length

resulted in a m a r k e d increase in plant height.
Runners;

Table X X shows that the num ber of runners

(an in dic a t i o n of the vegetative condition in the strawberry)
was signifi can tly g reater w i t h t emperatures ranging from
1|5° F to 7^° F ,in both the 0,1 and 0.5 H o a g l a n d ’s solutions
but only to 65° F in the 1,0 solution.

The production of

runners app ea r e d to reach a m a x i m u m in the 0,5 solution.
The 1,0 con ce n t r a t i o n fa iled to increase pr odu cti on of
ru nn e r s ,
Growns;

Root temperatures h ad greater effect upon the

dry wei ght ac c u m u l a t e d b y the crowns w h e n 0,5 H o a g l a n d ’s
solution was used.

There was a significant increase in

crown weight in 0©5 over that produce d in 0.1 H o a g l a n d ’s,
but raising the nutrient con centration to 1,0 failed to

T A B L E III
EFFECT OF R O O T T E M P E R A T U R E A N D CONC ENT RAT ION OF NUTRIENT
SOLUTION ON PET I O L E L E N G T H OF R OBINSON STRAWBERRY LEAVES

Root temoerature
(o P )‘

75
65

55
5-5

.
0.5

o.i

ram

mm

mm

123.61
111.22
89 . 69
72.12

128.67
118.23
88.52
68.09

107.08
92.02
69.1558.68

1.0

L.S.D.

- 5% = 13.17; 1% = 17.65

Averages b a s e d on I4. repli cat ion s of 2 plants each
of 8 plants).
Av era ges giv en are for 2 plants.

(total

38
Increase dry w e i g h t of crown.

Ro ot t e m p e r a t u r e s a n d solution

concentrations w e r e l e s s e f f e c t i v e on c r o w n d e v e l o p m e n t than
on any oth er p a r t of t h e pla nt.
Ton-Root Ratio
B o t h root t e m p e r a t u r e

a n d c o n c e n t r a t i o n of n u t r i e n t

solution h a d a p r o n o u n c e d e f f e c t on the ratio of top gro wth
to that of the r o o t s .

These

rat ios are g i v e n i n Table IV,

Each in cr e a s e i n root t e m p e r a t u r e
panied b y a s i g n i f i c a n t
regardless of the

of t e n degrees w a s a c c o m ­

i n c r e a s e in the top -r o o t ratio

c o n c e n t r a t i o n of t he n u t r i e n t

solution.

This w o u l d I n d i c a t e

that I n c r e a s e s In root t e m p e r atu re

fa\ror g row th of the

a erial p o r t i o n s

than gro wth of the r o o t
solution,
the

system*

to a g r e a t e r extent

The dilute,

0,1 H o a g l a n d ' s

f a v o r e d a r e l a t i v e l y l o w e r t op- roo t ratio tha n

solution.

to loO d i d n ot

R a i s i n g the c o n c e n t r a t i o n of the s olution

s i g n i f i c a n t l y inc rea se the r a t i o of tops to

roots o v e r that of the 0,5 solution.

The t op- r o o t ratio

was at a m a x i m u m in the 0,5 solution.
Plant Composition
Effect of Ro ot T e m p e r a t u r e on O r g a n i c C o m p o sition
The

a mo u n t s of c e r t a i n o rganic f r a c t i o n s c o n t a i n e d in

the l e a v e s

and roots as i n f l u e n c e d b y the

te mperatures
Protein,

are p r e s e n t e d in Table V and Fi gur es 5-8,

crude fiber,

nitrogen-free

series of root

e xtract

e t h e r ext rac tab le materials,

and

content of the le ave s were not

cantly i n f l u e n c e d b y r o o t te mper atu re variations.

signifi­

39

TABLE XV
EFFECT OF ROOT T E M P E R A T U R E A N D C ONC ENTRATION OF NUTRIENT
SOLUTION ON THE T OP- R O O T RAT IO OF ROB INS ON STRAWBERRY
Root temperature
(o P y

75
65
55
'4.5

C o n c e n t r a t i o n of Hoagland* s solution
1*0

o#5

6 #66

6.25

l+*75

5*56
3#80
1*8?

5.61

3*39

3.87
1*81

1.79

1*12

LoS.Do

0.1

- 5% - 0 .61+; ifo = 0.86

Averages b a s e d on 1+ r eplications of 2 plants each, (total
of 8 plants).
A ver a g e s given are for 2 plants#

TABLE V
EFFECT OF ROOT T E M P E R A T U R E ON T H E OR G A N I C CO M P O S I T I O N OF
THE R O O T S A N D L E A V E S OF R O B I N S O N S T R A W B E R R Y PLANTS
(Percentage D r y Weight)
O r g a n i c c omponents
Protein
Crude
Ether
fib er
extract

Root t e m p era tur e
(° P)

N-free
extract

Le a v e s
75
65
55
1+5
L eS *D.

—
i>

=
25

I+.8 I4.
1+.85
5.16
5.25

15*1+8
16,21
16,15
17 o08

1 0 . Ui+
10.1+0
10.13
10.06

N.S.

N.S.

N.S.

N.S.

16 . 1 3
17*1+6
16 .92
17.60

19 .96
18,03
15.21+
13.26

2,75
2.17
2,03
1,89

i+9. 21+
51.27
55.83
56.00

N.S.

1,21

0.1+7
0.72

2.67
1+. 01+

60.73
59.28
59.70
59.37

Roots
75
65
55
4-5
L.S.D.

N.S.

- 5$ =
1% =

1.83

-- F value not signifi can t

kl

P R 0 T E 1N

Leaves

20

conc. I . O
conc. 0 . 5

JZ
CO

conc.O. I

>\
Q2

Roots

conc.O.5
CL

conc.0.

45
Figure

\

75
65
55
Temperature
Ef fects of root temperature and concentration
of the nutrient solution on the protein con­
tent of the roots and leaves of the Robinson
strawberry (Using 1*0* 0*f? and 0*1 Hoagland* s
solution)«

k2

CRUDE

FIB ER

Leaves

c o n c . 1.0

o.i

o
conc. 0 . 5

.

Roots
We i g h t

one. 0. 1

Percent

Dry

c onc. 0 . 5

45
Figure 6.

55

65
Temperature

75

E f f e c t s o f root temperature and concentration
of the n u t r i e n t s olu t i o n on the crude fiber
co nte nt of the r oot s and leaves of the R o b i n ­
son s t r a w b e r r y (Using 1*0, 0.5> and 0®1
Hoagland* s s o l u t i o n ) «

k3

ETHER

EXTRACT

Leaves

Weight

conc. 0 . 5

Dry

conco. l

Percent

Roots

conc. O.

con c.0.5
o-

c o n c . 1.0

45
Fi g u r e 7.

55

65

75

Temperature
E f f e c t s of root te mpe rat ure and concentr ati on
of the n u t r i e n t sol u t i o n on the content of
e t h e r ext r a c t a b l e m a t e r i a l s in the roots and
l e a v e s of the R o b i n s o n st raw ber ry (Using 1.0,
0.5 and 0.1 H o a g l a n d ’s solution).

Root temperature aid influence tne amount of certain
oceanic constituents contained in the roots of these slants,

N-FREE EXTRACT

As fas found for leaves, the protein content was no: chanced
L e aves

in the roots by root temperatures ranging from 45° ? tc ?5° F,
the amount of crude fiber accraulatea by the roots increased
steadily from 45° F tc ]f ?, The aincunt of ether-extractconc.O,I

able materials was not significantly different at root
temperatures of 45°> 55°> ^ 65° F, At 75° ? there was

conc.O,5

a significant increase in ether-extractable materials,
Probably the most important and significant influence

conc. 1.0

of roc: temperature on the organic composition of these
strawberry plants was in the amount of nitrogen-free extract,

R oots

Accuiulation of the nitrogen-free extract fraction was
definitely favored by the lower root temperatures, The
greatest increase in the accumulation of nitrogen-free
extract occurred between ;$° ? and i>5° F,
conc.O,I
Effect of Concentration of Nutrient Solution on Organic
Composition
The data for the average percentage composition of
organic materials in relation to concentration of the
c o n c .1.0

nutrient solution are given in Table VI and are presented

Tonc.0.5

in Figures 5-8,
The concentration of the nutrient solution had no
significant effect on the percentage composition of crude

Temperature

cure 8, Effects of root temperature and concentration
of the nutrient solution on content of nitrogenfree extract in the roots andReaves of the
Robinson strawberry (Using 1.0, 0,5 ana 0,1
Hoagland's solution),

fiber and ether-extractable materials in the leaves biu
did influence the amount of protein and nitrogen-free
extract, The more concentrated solutions reduced the

14-6

T A B L E VI
EFFECT O F C O N C E N T R A T I O N O F N U T R I E N T S O L U T I O N O N T H E ORGANIC
C O M P O S I T I O N O F T H E R O O T S A N D L E A V E S OF R O B I N S O N S T R A W B E R R Y
( P e r c ent age D r y We igh t)
C o n c e n t r a t i o n of
nu tr i e n t s o l u t i o n
(Hoaglandl s)

Protein

O r g a n i c compone nts
Crude
Ether
fiber
extract

N-free
extract

Leaves
1.0

18.27
1 7 .2 lj.

0*5
0 .1

13.19
L.S.Do

- 5% =
1% =

1.37
2.07

10.13
10 .13

5.09
5.36
L<_06 I4.

56.14-9
58.12
6 k. 70

N.S.

N.S.

1 .14-6

10.51

2.21

Roots
20 ohf.2.
21.32

1,0

o.5
0.1

9. 35
L. S . D .

N.S,

- 5$ =
1% =

2 .0143.09

I 6 0 II4.
1 6 0I4.Q
17.26

1.7142.22
2.68

N.S.

O.Ul
0.62

-- F value n ot s i g n i f i c a n t

I4-8.87
I4.8 .8 I
61.58
2.31
3.50

k-1
nitrogen-free extract

content of the leaves.

There was

a significantly gr eater amount of proteinaceous materials
ore sent in the leaves of the plants grown in the 0*5 and
IcO Ho a g l a n d ' s
solution.

solution than in those grown in the 0.1

However,

the 1*0 solution concentration did not

significantly increase the p rot ein content of the plants
over that of the 0*5 Hoagland* s solution.
I n the roots,

as In the leaves,

the so lut ion did not
of crude fiber,

the concentration of

significantly change the percentage

but did affect the content of protein,

ether-extract an d n itr ogen-free extract.

The roots h a d the

same pr o t e i n content w h e n grown in a 0*5
l a n d ’ s solution*

in a 1.0 H o a g ­

At a concentr ati on of 0.1,

very m a r k e d r e d u c t i o n in pro tein content*

there was a

There was more

ether-extractable materia l present w i t h lower concentrations
of the nut rie nt solution.

The percent age dry weight of

nitrogen-free extract was essentially the same w h e n grown
in a 1*0 as in the 0*5 Hoa gla nd* s solution.
basis,

there w a s

On a percentage

a large increase in these materials when

the co nc e n t r a t i o n of the solution was r ed u c e d to 0,1
Hoagland*s•
Effect of Root Temperature on A s h Composition
The average percentage composition of total ash and of
eight of its constituents found i n the leaves and roots of
the plants g row n at various root temperatures are evaluated
statistically in Tables VTI and VIII.

A summary of some of

these results are to be found in Figures 9-13®

TABLE VII
EFFECTS OF ROOT TEMPERATURE ON THE NUTRIENT-ELEMSNT COMPOSITION OF THE ROOTS
AND LEAVES OF xROBINSON STRAWBERRY PLANTS

(percentage Dry Weight)
Root
temperature

K

\o F)

P

Ca

Nutrient elements
B
Mg

Fe

Mn

Cu

Total
ash

Leaves
2,37
2.29
2.23
2.15

•740
.923
.8^2
.996

2028
2,01).
1.69
2.06

%=

0.15

N.S,

N.S.

1%-

0.22

75
65
55

k-S
L.S.D. -

.502
.638
.699

•.0125
0OIO7
.0119
.0110

.021}.
.025
.025
.030

.612
.740
1.306
.901

,0005
.0010
.0008
o0008

U.S.

N.S.

N.S.

N.S.

N.S.

N.S,

•490
.502
.559
.602

,0019
,0020
.0024
.0021

.633
.800
.533
.767

,0001
.0001
,0001
,0001

11.92
11,06
9.98
11,25

N.S.

N.S.

N.S.

.55^

8.51
9.27
8 .8 7
8.23

Roots
IS

1.98
1.20
1.57
2.07

.819
.506
403
•407

~ N.S.

N.S.

65
55

kS
L.S.D. -

%

.228
•240
.227
.133

N.S.

ii =
N.S. -- F value not significant

.025
.030
.033
,020

N.S.

N.S.

1,32
1.90

TABLE VIII
EFFECTS OF THE CONCENTRATION OF THE NUTRIENT SOLUTION ON THE NUTRIENT-ELEMENT
COMPOSITION OF THE ROOTS AND LEAVES OF ROBINSON STRAWBERRY PLANTS
(Percentage Dry Weight)

Cu

Total
ash

Nutrient elemer L;i

Solution
concentration
(Hoagland* s)

K

P

Ca

Mg

B

Fe

Mn

Leaves
l o0

247

1.288

1.59

.636

.0170

.019

.796

.0012

9.65

o.5
0.1

2.23

.861

1.58

.0108

.025

.078

.0007

9.16

2.08

.477

2.83

•544
.613

,0068

.035

1.800

.0005

7.35

0.13

,o393

.85

N.S.

.0025

.007

N.S.

N.S,

0,81

0.19

.617

1.38.

.0040

.011

.700

.066

.0002

12.83

.700

.013
.002

.0001

11,19

.000.1-

9.14

.015
.024

N.S,

1.09

L.S.D. -

%=
1i =

1.22

Root3
1.0

2.13
2.16

0.5
0.1

143

L.S.D. -

=

!=

i

0.55
0.87

1.008

.353

.536

.313
.281

.135

.623

.0027
,0020

.138

•455

*001?

.650

.302

.169

.0004

N.S.

4?4

.265

N.S.

.0006

I 064

N.S. -- F value not significant
-F~
vO

50

TOTAL

ASH

Leaves
O-

Wei ght

„conc. 0.5

Dry

conc. O.

Per cent

Roots
14

conc. 0- 5

conc. O.

45
Fi g u r e 9.

55

65
T emperatur e

75

Ef f e c t s of root temperature and concentration
of the nu tri ent solution on the ash content of
the roots an d leav es of the R obi n s o n strawberry
(Using 1,0, 0,5 and 0.1 Ho a g l a n d * s solution).

Si

PO TASSIUM

3. 0

Leaves

conc. I . O
2.5
c o n c . O .5
c o n c . O. I

1.5

Ory

Weight

2.0

Roots
c o ne . I .O
^
00. 5
u
conc. 0 . 5

Q2.0

conc-O. I

1.0

45

Pisure 1 0 •

€ 5
55
Temperature

75

E f f e c t s of r o o t t e m p e r a t u r e a n d c o n c e n t r a t i o n
of t he n u t r i e n t s o l u t i o n o n the p o t a s s i u m con
te nt o f t h e r o o t s a n d l e a v e s of the R o b i n s o n
s t r a w b e r r y ( Usi ng 1*0, 0*^ a n d 0»1 H o a g l a n d 1 s
solution)o

£2

PHOSPHORUS
1.6

Leaves

1.2

c onc.O.5

A

c o n c . O. I

Dry

Weight

.8

Percent

Roots
1.3

.9

•5
conc. 0 . 5
_
o
c o n c. O. I
.1
55°
Tem perature
F i g u r e 11®

65

75

E f f e c t s of root t e m p e r a t u r e a n d c o n c e n t r a t i o n
of t he n u t r i e n t s o l u t i o n on the p h o s p h o r u s
c o n t e n t of the r o o t s and l e a v e s of the R o b i n ­
s o n s t r a w b e r r y (Using 1*0, 0*5 aud 0*1 H o a g —
land* s s o l u t i o n ) •

£3

CALCIUM
3.7

Leaves

,JD

2. 9

Weight

2.1
conc. I
conc. 0.5

Perc ent

Dry

3

Roots

.5

.4

3

2
conc. 0.5
con c. 0.1

.I
45
Figure 12,

55
T empera ture

65

75

Effects of root temperature and concentration
of the nutrient solution on the calcium con­
tent of the roots and leaves of the Robinson
strawberry (Using 1.0, 0*5 and 0*1 H o a g l a n d 1s
so lut ion )«

5ii

MANGANESE

Leaves
3. 0

Percent

c o n c . !.

.0

—

conc.O.

Dry

Weight

2.0

a

c o n c. 0. 5

Roots

08h

conc
.06

.041

.02 j
-

c o n c. O. 5

conc
.0 0

-

4 5

6 5

55

75

Temperature

r i ;■u_re 1 ^ «

Zff'ects of rcor rezre rature ana eon ;entr£ticn
janese ecu­
cf the nutrient solution on one
tenc oi the roots and leaves of be Robinson
strawberry (Using 1 .0 , 0*5 and u ,1 H o a n l a n d ’s
solution)c

W i t h but one exception,
total ash no r any of its
Mn,

Cu)

n e i t h e r the p e r c e n t a g e of*

compon ent s

in the l e a v e s w e r e

Ca, Mg,

B, Fe,

s i g n i f i c a n t l y i n f l u e n c e d b y root

temperatures f r o m L\.$° F to 75° F.
in p o t a s s i u m content.

(P, K,

There w as

The one e x c e p t i o n w a s
a t r e n d of in cre a s i n g

content of p o t a s s i u m w i t h i n c r e a s i n g t e m p e r a t u r e f r o m

F

to 75>° P.
The fact that d i f f e r e n c e s in m i n e r a l
leaves

content of the

and roots was o b t a i n e d w i t h changes in c o n c e n t r a t i o n

of the n u t r i e n t

s o l u t i o n l end s s upport to the a s s u m p t i o n

that the above f ind ing s w e r e no t a result of i n a b i l i t y of
the analytical m e t h o d s u s e d to a c c u r a t e l y m e a s u r e the d i f f e r
ences,

Since,

all of the plant m a t e r i a l of the plant pa rt

in q u e s t i o n p r o d u c e d b y eight p l a n t s i n four re pl i c a t i o n s
was c o m p o s i t e d to o b t a i n the sample used,

it w o u l d seem that

lack of di f f e r e n c e s can not be a t t r i b u t e d to sa mpl ing m e t h o d s
W h i l e there w e r e

s i g n i fic ant dif fer enc es

in the total

ash content of the r o o t s that could be l i n k e d to differences
in root temperature,

these c o u l d not be a t t r i b u t e d s ta t i s ­

tically to any of the eight n u t r i e n t ele men ts for w h i c h
determin ati ons w e r e made.
the roots,

a p p e a r e d to b e

The p e r c e n t a g e of total ash in
a ffe c t e d b y the c o n c e n t r a t i o n of

the s o l u t i o n u s e d at l o w t e m p e r a t u r e s
less effect at 55° F,
and above,
mineralSo

However,

(l{-5?0 F) •

T here was

w i t h te mpe rat ure s of 5>£° P

there was a f u r t h e r increase in total content of

£6

Effect of Nut rie nt C o n c e n t r a t i o n o n As h C o m p o s i t i o n
Table VXII

an d F i g u r e s 9-13 stow that the c o n c e n t r a ­

tion of the nut ri e n t sol uti on h a d a mo re p r o n o u n c e d effect
on the m i n e r a l content of the s t r a wb err y t han did root
temperature .
The total ash content of the leaves inc rea sed w i t h
greater concent rat ion s of the nu tr i e n t

solution.

However,

total ash of the le a v e s of p la n t s g row n in the 1.0 solution
was not sta t i s t i c a l l y greater than that of plants g r o w n in
the 0o5 solution.

The per cen t a g e

content of potassium,

phosphorus and boron in the leaves i n c r eas ed w i t h h i g h e r
concentrations of the n utr ien t solution,

w hereas that of

calcium and iron was less w i t h h i g h e r con centrations of the
nutrient solution.

There w a s no significant change in the

percentage content of magnesium,

man ganese and copper in

the leaveSo
The total ash content of the roots increased w i t h each
concentration increment of the H o a g l a n d ’s solution.

There

was no significant change in the c o m p os iti on of the roots
with respect to magnesium,

iron,

a nd c opp er associated w i t h

concentration of the n utr i e n t solution.

Phosphorus,

calcium

and m ang a n e s e i n c r e a s e d w i t h concent rat ion increments of
the Hoagland* s solution.

There was an increase in the

potassium and boron content of the roots a sso cia ted w i t h
increasing so lut ion concentration.

The p o t a s s i u m content of

the roots was not sig nif ica ntl y increased w h e n the c onc en­
tration of the nut rient solution was changed from 0,5 to
1.0 H oagland*So

C o r r e l ati ons
U s i n g the r e s u l t s of the analyses,
determined for v a r i o u s con sti tue nts *

co rre lat ion s were

Cor r e l a t i o n s or

relationships b e t w e e n the o rgan ic f r a c t ion s and nu tri ent
elements of the p l a n t aid in the i n t e r p r e t a t i o n of the
effects of root t e m p e r a t u r e s a n d n utr i e n t
growth b e h a v i o r of these

i n t e n s i t y on the

s t r a w b e r r y plants*

Since nit rog en-

free ex tract a n d p r o t e i n w e r e the two organic con sti tue nts
that are d i r e c t l y r e l a t e d to the p h o t o s y n t h e t i c - r e s p i r a t o r y
balance

and m a y be in a form that is u t i l i z e d eit her in

growth or respiration,

the trends in per cen tag e c om p o s i t i o n

of these two con s t i t u e n t s w e r e c o r r e l a t e d w i t h e a c h other
and also w i t h that of total ash and c e r t a i n nu tri ent elements
N-Free E x t r a c t and P r o t e i n
A si g n i f i c a n t c o r r e l a t i o n was f o u n d i n b o t h l e a f and
root tissue b e t w e e n the p e r c e n t a g e of n i t r o g e n - f r e e extract
and p r o t e i n content

(Figures Ilf and 15) *

The c oefficient

of c o r r e l a t i o n w a s - O 086 I4. for root tissue and -0«98I(. for
leaf tissue*

These neg a t i v e correlations

in dic ate d that

increases in the p e r c e n t a g e of prot e i n a c e o u s ma te r i a l

in

the leaves a n d roots w a s a c c o m p a n i e d w i t h decreases in the
p e r c en tag e of carbohyd rat e fractions*
N-Free E x t r a c t

and Total A s h

The r e l a t i o n s h i p s b e t w e e n the percenta ge nit rogen-free
extract and total ash,

on a dr y weight basis,

in the roots

and l eav es are i l l u s t r a t e d in Fi gures 16 and 17o

A coeffi-

58

67
ROOTS

62

o
o

71.00
57

IV

OJ
L_
U(
z 52
cr
IV

o
<v
CL

47 !

12
Percent
Figure 11}.,

15
18
Protein

2I

2 4

Re lat ion shi p b e t w e e n percentage of nitrogenfree extract and percentage of p rot ein on a
dry we ight basis in the roots of Robinson
s trawberry plants subjected to various root
temperatures and nutrient concentrations*

Coefficient of C o r r e la tion =

-0*861}.

59

LEAVES

Per cent

N-Free

Extract

70

65

60

oo1

55

50

13
Per c e n t

Figure l 5 •

15

17

19

21

Protein

R e l a ti ons hip b e t w e e n percentage of n itr o g e n
free extract a nd percentage of pro tei n on a
dry w e i g h t b a s i s in the leaves of R obi nso n
s t ra wbe rry plants subjected to va rious root
temperatures and nutrient concentrations®

C oefficient of C o r r e l a t i o n —

-0»98ij.

60

ROOTS

Extract

63

53

Percent

N-free

58

48

43

7 .0

Figure 16,

9 .0
Percent

13.0
Ash

R e l a t ion shi p b e t w e e n percenta ge of nitrogenfree extract and percentage of total ash on
a dry wei ght basis in the roots of R obinson
strawbe rry plants subjected to various root
temperatures a nd nutrient c o n c e n t r a t i o n s 0

Coeffic ien t of C o r r e lat ion =

-0*837

61

LEAVE S

65

N- Fr ee

Extract

70

Percent

60

°o

55

50

6.5

7. 5
Percent

Figure 17•

8.5
Ash

9.5

10.5

R e l a t i o n s h i p b e t w e e n p e r c e n t a g e of nitrogenfree ex tract and p erc ent age of total ash on
a dry w eight basis in the leaves of R o b i n s o n
st raw ber ry plants subjected to various root
t e m p e rat ures and nutrient concentrations®

C o e f f ici ent of C o r r e l a t i o n =

-0*906

62

cient of c o r r e l a t i o n of -0 * 9 0 6 w a s o b t a i n e d for these
fractions in the l eav es a n d -0 *83 7 in the roots*
negative

c o r r e l ati ons

These

sho wed that in cre ase s in total ash

content of the l e a f and root tissues w e r e

accompanied by

decreases in the u t i l i z a b l e

(nitrogen-free

carbohydrates

extract)*
N-Free E x t r act a n d P o tas s i u m
Since p o t a s s i u m w a s the

on ly constit uen t of the total

ash that sh o w e d s i g n i f i c a n t d i f f e r enc es in p e r c e n t a g e
c omposition as a result

of changes in root temperature,

comparison was made b e t w e e n the pe rce n t a g e
element and that of the organic
n i t r o gen -fr ee
obtained

extract.

a

content of this

component m e a s u r e d as

S ig n i f i c a n t correla tio ns were

(Figures 18 and 1 9 ) o

I n the leaf tissue the

coefficient of c o r r e l a t i o n b e t w e e n content of ni tro g e n free extract and p o t a s s i u m w as
it was - 0 *7 3 1 o

- 0 o687j w h i l e in the roots

63

ROOTS

58

N- f r ee

E %t r a c t

63

Percent

53

46

4 3

2.0
Percent

Fi gure 18.

2.5

3.0

K

R e l a t i o n s h i p b e t w e e n p e r c e n t a g e of n i t r o g e n free extract and p erc en t a g e of p o t a s s i u m on
a dry w e i g h t basis i n the roots of R o b i n s o n
s t r a w b e r r y plants s ubj e c t e d to various root
t e m p e r atu res and n utrient concentrations*.

C o e f f i c i e n t of C o r r e l a t i o n = —0.731

6Ij.

LE AVES

60

N- f r e e

Ext ract

65

Percent

55

50

45

2.0

F i g u r e 19*

2.1

2.2

2.3
Percent

2.4

2. 5

2.6

K

R e l a t i o n s h i p b e t w e e n pe r c e n t a g e of n i t r o g e n free ex tract and per cen t a g e of p o t a s s i u m on
a d r y w e i g h t basis in the leaves of R o b i n s o n
s t r a w b e r r y plants su bje cte d to va rious root
t e m p e r a t u r e s a n d n u t r i e n t con centrations®

C o e f f i c i e n t of C o r r e l a t i o n = -0*687

DISCUSSION
In in ter pre tin g the results of these studies it should
be kept in m i n d that the plants were in a stage of develop­
ment w her e ve ge tat ive e x t e n s i o n of bot h the tops and roots
was taking p l a c e 0

The

aerial environ men t of the plants

during this p e r i o d of development w o u l d be

comparable both

in temperature and light i n t e n s i t y to those found u n d e r
normal M i c h i g a n field conditions.

The p e r i o d of time

in

wh ich the vegetative gr owt h was m ade in this experiment m ay
be con sid e r e d comparable

to that found in the f iel d during

the spring and stttnmer w h e n n e w l y pla n t e d strawberry plants
are m a k i n g their vegetative growth*
Root Temperature

in Relation to G-rowth and Develop men t

The data o b t a i n e d in these

studies ind ica ted that,

during the vegetat ive p e r i o d of development,
of aerial portions of the plant

(leaves,

the pr odu c t i o n

petioles,

crowns and

runners) was cl ose ly cor rel ate d w i t h root temperatures.

As

temperatures were v ari ed from 1+^° P to 65° F there was a
progressive increase in the dry we i g h t of these plant parts
and also In the he i g h t and 3pread of the plants as a result
of i nc re a s e d petiole length.

This increase In vegetative

extension was also expressed in increased numbers of leaves
and runners.

Since there was no significant increase in the

66
weight of these ve g e t a t i v e portio ns of the plant w i t h an
additional increase i n root tempera tur e to 75>° F,

it w o u l d

appear that root t em p e r a t u r e s b e t w e e n 65>° F and 7f?° F were
approximately " o p t i m u m ” for growth and d evelopment of this
variety of st raw ber ry un der normal or average conditions of
light and air temperature*
b e t w e e n root temperature

The close c orrelation ob ser ved

and shoot growth w i t h i n certain

temperature limits wa s in agreement w i t h that f o u n d for
apples

(Nightingale,

193£; Batjer,

stlng,

19i|-3) an d roses

1939),

peaches

(Shanks a nd Laurie,

(Proeb-

19l|-9)o

ditions for g r o w t h were w holly adequate in these

If con­
studies,

the r esults w e r e not in agreement w i t h those of Went, who
was of the o p i n i o n that,
able,

if growing conditions are f a v o r ­

root temperature h a d v e r y little if any effect on

total plant

growth.

As ob ser ved b y Shanks and L aur ie

(19l|-9) w i t h roses

and b y others w o r k i n g with field crops,

there was also a

striking increase in top-root ratio w i t h each increment in
root temperature from

to 75° F*

This in dic ate d that

high root tem peratures favored growth of the top mo re than
that of the r o o t s 0
A l t h o u g h there was no significant difference in the
weight of roots p r o d u c e d at root temperature Increments from
14-5° to 75° F,

there w as a steady,

if but slight,

decrease in

root w eight w i t h each increase in root temperature,
in the two h i g h e r nutrient c o n c e n t r a t i o n s 0

especially

This was In

agreement w i t h the results o btained by Stuckey (19li2),

67

Br own (1939),
and b y D i c k s o n

and Darrow,
(1923)

R. A.

and W o r t

(1939)

for forage grasses

(191^0) for grains.

These

workers o b s e r v e d les s root w e i g h t as soil, t e m p e rat ure in­
creased w i t h i n the range of soil t e m p e r a t u r e s o c c u r r i n g
during the g r o w i n g season.

E a r l e y and C a r t t e r

(191+5) called

attention to t he fact that l ight in ten s i t y m a y be a fa c t o r
in d e t e r m i n i n g the amount of root growth r e s u l t i n g from
increases i n root temperature.
co nsi der ed as a l i m i t i n g factor,

L i g h t i n t e n s i t y was no t
however,

during the p e r i o d

of this experiment.
The type of root s yst em p r o d u c e d u n d e r the s everal root
t e mperatures c o m p a r e d in a general w a y w i t h those d e s c r i b e d
b y Ni g h t i n g a l e
peach,

(1935>) a^d b y B a t j e r

(1939)

for apple and

Stuo cey (19^-2) for grasses and Shanks

(19li9) for roses.
we re x^hite,

and La u r i e

At r e l a t i v e l y low temperatures the roots

tr ans luc ent

and r e l a t i v e l y unbranched.

At

h i g h e r te mpe rat ure s

the ro ots t end ed to be mo re

slender and

p r o f u s e l y branched.

At the h i g h e s t tem per atu re

(7f?° F) the

roots w e r e finer, more fibrous and less extensive than at
the l o w e r temper atu res .
various root materials,
mo r p h o l o g i c a l

Sections p r e p a r e d fr om these
showed,

in general,

the

same

d ifferences d e s c r i b e d by N i g h t i nga le

(1935>) in

his studies w i t h the apple and peacho
W h e n the total g row th of b o t h aerial and root portions
were considered,

it was apparent that a root temperature

b e t w e e n 6£° and 75° F was m o s t favorable for m a x i m u m dry
we i g h t a c c u m u l a t i o n during the p e r i o d of vegetative ex ten ­
sion.

68
Co ncentration of Nutrient Solution in Relation to
Growth and Development
The concentration of the nutrient solution was appar­
ently near optimum at 0.5> H o a g l a n d ’s,

The 0.1 solution was

too dilute even though re newed at frequent intervals.
creasing the

In­

concentration of the nutrient solution above

the " o p t i m u m 11 (0..^ H o a g l a n d ’s) h a d no significant effect on
top growth w h e n root temperatures were bel ow 5£° F.

There

was no difference in dry w eig ht pr odu cti on of the tops*
However,

increasing the concentration of the solution to

1.0 H o a g l a n d ’s w h e n the root temperature was 65° F pro ved
detrimental to growth of the tops.

This detrimental effect

of added concentr ati on of nutrient salts was reduced b y
further increase of root temperature to 75>° F*
The above results appeared to support the hypothesis
that, un d e r certain conditions,

salt concentration m a y i n ­

crease respiration to the extent of deple ting organic
reserves at h i g h e r root temperatures.

Un der the conditions

of the growth period during this experiment, m a x i m u m growth
of the tops was obtained at nutrient concentrations far
below those that were used i^ithout visible injury to the
root system.

Total growth of the top was less at higher

nutrient concentrations,
V e r y dilute

if root temperatures were high.

solutions

(0.1 H o a g l a n d ’s) even though

continually renewed resulted in less total growth of roots.
As in the case of the aerial portions of the plant maximum
growth was obtained at a nutrient concentration of 0<>5»

69

which was m u c h bel ow that of 1,0,

W h i l e thore w a s no

significant difference in the dry we i g h t of roots pr oduced
by increasing the concentration of the nutrient solution
from

to 1 80j there was a tendency for root production

to be slightly greater at all temperatures in the 0.£ than
in the 1.0 H o a g l a n d 1s solution.

This gave further support

to the conclusion that excessively h i g h salt concentrations
can result in less total growth even in the absence of
visible signs of injury.
Both root temperature and the concentration of the
nutrient solution h a d greater effects on dry weight p r o ­
duction of aerial portions of the plant than on those of
the rootso

This indicated that,

tative extension of the plant,

during the period of vege­

the aerial portions were

more subject to influence from changes in these en viron­
mental conditions 0
Root Temperature in Relation to Plant Composition
Organic Composition
Al tho ugh root temperature h ad a profound effect on the
total growth of the aerial portions of the plant,

the organic

composition of the leaves remained unchanged for the different
root temperatures.

X f there were any changes in assimilation,

translocation or utilization of organic materials as a result
of changes in root temperatures from

to 75° F, they

were not detectable in the percentage composition of the
various organic fractions of the foliage used in these tests.

70

The significant changes in the organic composition of
the roots associated wi th root temperature indicated that
the effect of temperature on organic constituents were more
or less localized©

The increases in crude fiber and ether-

extractable materials w h i c h were accompanied by decreases
in nitrogen-free fractions and associated w i t h increasing
root temperatures,

indicated that respiration and m a t u r ­

ation processes w ere increased w i t h higher root temperatures©
Since,

the above changes in organic composition were

not accompanied w i t h increased total dry weight of the plant,
they were only an indication of a normal

shift in composition

related to increased growth and met abo l i s m as a result of
increased root temperature w ith in the optimum r a n g e 0

The

lowest root temperatures used in this series of treatments
were

sufficient t > reduce either assimilation or trans-

location,

or both,

tops was reduced©
not

to the extent that total growth of the
However,

the highest temperature was

sufficient to reduce growth through depletion of carbo­

hydrate reserves of the roots as was found b y Nightingale
and Blake

(193^4-) t Hewitt and Curtis

(19^-3), Benedict

(19^0),

et al w o r k i n g w i t h excessively h igh root temperatures on
other cropso
Total A3h and Nutrient-Element Composition
On the basis of the data obtained in these studies,

root

temperatures appeared to have very little if any appreciable
effect on the mineral

composition of the aerial parts of the

71

plant during the vegetat ive phase of development*

There

was no significant increase in the percentage of total ash
in the leaves a s s o ci ate d w i t h the Increased dry wei ght pro ­
duction that r e s u l t e d from in creased root temperature.

Of

the several nut rient elements de ter m i n e d in composition
analyses,

on ly pot as s i u m

showed a significant change in

relation to root temperature.

The percentage of leaf

po tassium i ncr eas ed w i t h h i g h e r root t e m p e r a t u r e 0
The different root temperatures influe nce d the ash
content of the roots more than they influenced the ash
content of the leaves.

At temperatures above 55>° F,

the

total ash content of the roots w a s inc rea sed w ith h igher
temperature.

However,

at l\.$° F the ash content of the

roots was net significantly different from that at the
hi ghest

(75° F)

temperature, w h i c h m i g h t indicate a con­

centration effect r esu lti ng from r e d u c e d growth.
The tendency for the ash content of roots to increase
w i t h hi ghe r temperatures indicated that salt accumulation
ma y occur at the expense of certain organic constituents,
w h i c h supply energy release,
decrease in growth.

Also,

because there was also a

the effects of temperature on

percentage mi neral composition of plant tissues appeared to
bo more or less l o c a l i z e d in the plant part subjected to the
temperature differences.

This further supported the h y p o t h ­

esis that mo vem ent of nutrient elements within the plant
was dependent upon respirable organic materials and energy
from th em at greater rate w i t h h igh er t e m p e r a t u r e s 0

72

The e v i d e n c e o b t a i n e d in t h e s e
r e v i e w e d in the li t e r a t u r e ,
strate
was

was not

studies,

and those

s u f f i c i e n t te d e m o n ­

that the r e d u c e d r a t e of g r o w t h at l o w t e m p e r a t u r e s

due to a r e d u c t i o n in a b s o r p t i o n of n u t r i e n t e l e m ent s*

Mo re g r o w t h w a s m a d e b y p l a n t s g r o w n in the 0*5> t h a n in the
1„0 H o a g l a n d ’ s s o l u t i o n e v e n t h o u g h the amount of n u t r i e n t
elements a b s o r b e d b y the p l a n t s

in the 1 * 0 H o a g l a n d ’s

so lut ion *ras g r e a t e r at all root t e m p e r a t u r e s ®
C o n c e n t r a t i o n of the N u t r i e n t S o l u t i o n in R e l a t i o n
to C o m p o s i t i o n
O r gan ic C o m p o s i t i o n
.Although the t o t a l c o n c e n t r a t i o n of salts in the
n u t r i e n t s o l u t i o n h a d n o a p p r e c i a b l e effect on the p e r c e n t ­
age of cru de f i b e r
influence

and o t h e r - e x t r a c t a b l e ma t e r i a l s ,

the p e r c e n t a g e of n i t r o g e n o u s

ex t r a c t a b l e

constituents

it did

an d n i t r o g e n - f r e e

in b o t h the l e a f an d root tissue*

M a x i m u m g r o w t h of the p l a n t w a s n ot a s s o c i a t e d w i t h e ither
the h i g h e s t p e r c e n t a g e of p r o t e i n or of n i t r o g e n - f r e e
extracbo

The

small

dilute n u t r i e n t

amount o f g r o w t h of the plants

s o l u t i o n r e s u l t e d in an e x c e s s i v e l y h i g h

c a r b o h y d r a t e - n i t r o g e n r e l a t io nsh ip.
n u t r i e n t s o l u t i o n there w a s
re la t i o n s h i p *

in the

X n the mos t c o n c e n t r a t e d

a lower carbohydrate-nitrogen

An intermediate

r ela t i o n s h i p a p p e a r e d to

exist for t h o s e p l a n t s g r o w n in the 0*5 H o a g l a n d * s
m a x i m u m g r o w t h wa s obt ai n e d *

A

sol ution

shift In the c a r b o h y d r a t e -

n i t r o g e n b a l a n c e was a c c o m p l i s h e d b y cha ngi ng the c o n c e n ­

73

tration of the n u t r i e n t s o l u t i o n e v e n t h o u g h the same
relative p r o p o r t i o n of salts in the so lu t i o n w a s ma i n t a i n e d #
These d i f f e r e n c e s in organic c o m p o s i t i o n w e r e mo re
obvious in l o a v e s than in the roots of the p l a n t s grown
with the h i g h e r salt
concentrations*

c o n c e n t r a t i o n s but less

so at l owe r

W h e n l o w n u t r i t i o n l e v e l s exist,

the

demands of m a t e r i a l s m a n u f a c t u r e d i n the leaves f o r n i t r o g e n
constituents a p p e a r e d to be d o m i n a n t over those of the roots*
W h e n the re was no di ffe r e n c e

in the dry w e i g h t of roots

res ulting f rom the 0 o5> and 1* 0 H o a g l a n d 1 s solutions,
was,

likewise,

no d iff ere nce

and c a r b o h y d r a t e components*

there

in the p e r c e n t a g e of pr ote in
Greater leaf production

re sulted i n s l i g h t l y l o w e r content of p r o t e i n and si g n i f i ­
cantly h i g h e r carbohy dra te

compone nts

(N-free extract)*

Total A s h a n d N u t r i e n t E l e m e n t C o m p o s i t i o n
The c o n c e n t r a t i o n of salts in the nu trient solution
had a m a r k e d e f f e c t on b o t h the total ash content and several
ash constituents,
bo r o n a nd iron«

e s p e c i a l l y potassium,
This was

H o a g l a n d and B r o y e r
for o t h e r plants.

phosphorus,

calcium,

in a gre ement w i t h the findings of

(193&),

and W a n n e r

(19i-u8) cited ea rli er

The p e r c e n t a g e of total ash i n c r ea sed

si g n i f ica ntl y w i t h eac h increase in the relative c o n c e n t r a ­
tion of the

solutions.

This

in b o t h roots and leaves.

increase in total ash was f o u n d

However,

no t all nu tri e n t elements

in creased in p e r c e n t a g e co m p o s i t i o n w i t h increases in
solution concen tra tio n.

Although,

potassium,

phosphorus

7k
and b o r o n i n c r e a s e d in the l e a f tissue as the s o l u t i o n
c o n c e n t r a t i o n increased,

c a l c i u m and i r o n d e c r e a s e d in

pe r c e n t a g e of d r y w e i g h t *

However,

the above n u t r i e n t el eme nts

in root

tissue all of

i n c r e a s e d in p e r c e n t a g e content

with h i g h e r s olu t i o n co nce ntr ati ons *
There w a s

an i ncrease in total ash in b o t h the roo t

and le af tissue w i t h i n c r e a s e d s o l u t i o n c o n c e n t r a t i o n
regardl ess of root t e m p era tur e.

Since m a x i m u m g r o w t h was

o b t a i n e d in the 0 0£ H o a g l a n d 1 s solution, w h e r e ash content
of the p l a n t s was c o n s i d e r a b l y b e l o w tha t f o u n d in p lan ts
grown in the 1 * 0

solution,

have o c c u r r e d for

’’l u x u r y a b s o r p t i o n ” app ea r e d to

several of these elements*

This "luxury

a b s o r p t i o n ” of n u t r i e n t elements a p p e a r e d to b e a c c o m p l i s h e d
at the expense of or gan ic reserves.
(1936),

H o a g l a n d and B r o y e r

b e l i e v e d that nut r i e n t element a b s o r p t i o n was

af fec ted t h r o u g h an e n e r g y exchange m e c h a n i s m w i t h the
energy b e i n g s u p p l i e d b y res pir a b l e

substrates.

se emed to be some support for this hypothesis,

There
since there

was a c t u a l l y r e d u c t i o n in total g r o w t h w h e n roo t t e m p e ra tur es
we re 65>° and 75° F and the c o n c e n t r a t i o n of the n u t r i e n t
solution was i n c r e a s e d f r o m 0 o5 to 1 . 0 o

This w a s a c c o m ­

p a n i e d b y r e d u c t i o n in the p e r c e n t a g e of res pir abl e c a r b o ­
h y d r a t e m a t e ria ls.

Also,

the h i g h e s t p erc en t a g e of total

ash in the p l a n t t iss ues was not a s s o c i a t e d w i t h m a x i m u m
growth of the ro ots or fcopso
Wanner

(194-8) was of the opinion that less e n e r g y was

re qui red to r emo ve

salts f r o m solutions of h i g h c onc e n t r a t i o n

75

than so lut i o n s of l o w c o n c e ntr ati on.

Perhaps the obs erv ed

•’l u x u r y ” a c c u m u l a t i o n f r o m solutions of h i g h c o n c e n tra tio n
was not

e n t i r e l y at the expense of r e s p i r a b l e reserve

hydrates.

Howeve r,

ca rbo ­

the r e d u c e d d r y w e i g h t p r o d u c t i o n or

e f f i ci enc y of m o r e c o n c e n t r a t e d solutions at h i g h e r root
temperat ure s d i d no t o c c u r in solutions of s imilar c o n c e n ­
trations at l o w e r t e m p e r a t u r e s
Q10 ratings f o u n d b y W a n n e r

(lj.50 - 55° F) •

The l o w e r

(19^4-8) for mo re c o n c e n t r a t e d

solutions were not o b s e r v e d in these studies*
R e l a t i o n of C o m p o s i t i o n to G rowth
The

signific ant n e g a t i v e c o r r e l a t i o n fou nd b e t w e e n

n i t r o gen -fr ee ex t r a c t

and p r o t e i n content was suggestive

of the long ac ce p t e d r e l a t i o n s h i p b e t w e e n carboh ydr ate and
n i t r o g e n in the p lan t

(Kraus and Kraybill,

1913)*

Greater

amounts of n i t r o g e n o u s m a t e r i a l s in the plant w e r e ac com ­
p a n i e d b y l e s s e r amounts of m e t a b o l i z a b l e
fr actions
processesc

(nitroge n-f ree extract)

carbohydrate

n e c e s s a r y for assimilatory

Plants mailing the m a x i m u m amount of growth,

on the b a s i s of dry w e i g h t production,
ratio of n i t r o g e n - f r e e
components of 59:1?

h a d an approximate

extract to p r o t e i n or nitrogenous

(3«>5) in l e a f tissue

and 5 2 : 2 0

(2.6)

in root tissues*
The inverse r e l a t i o n e s t a b l i s h e d b e t w e e n nitrogen-free
extract and total

ash was e s p e c i a l l y significant in that

m a x i m u m gr o w t h was not a s s o c i a t e d w i t h the hi g h e s t ash c o n ­
tent of the roots and foliage.

Since,

content of nitrogen-

76

free extract w a s l o w e r w i t h h i g h e r ash content,

the i n ­

crease in ash content above t hat n e c e s s a r y f o r m a x i m u m
growth a p p e a r e d to r e s u l t f r o m the u t i l i z a t i o n of carbo­
hydrate ma t e r i a l s *

This a p p e a r e d to be e s p e c i a l l y true

with c ond iti ons of low p h o t o s y n t h e t i c efficiency,

and

agreed w i t h evidence p r e s e n t e d in p r e v i o u s l y c i t e d literature.
The c o m p o s i t i o n of the plants
amount of total

dry w ei g h t i n d i c a t e d that the ratio of

n i t r o g e n - f r e e e xtract to total
(6*6)

that p r o d u c e d the largest

ash w a s a p p r o x i m a t e l y 59:9

in l e a f tissue and w a s a p p r o x i m a t e l y 5 0 : 1 1

(ip. )

in

root tissues
A significant n e g a t i v e correlation,
relatio n to total

si m i l a r to that in

ash, was found b e t w e e n the ni tro gen -fr ee

extract an d p o t a s s i u m in the tissue.
Plant tissue analysis '/as c o n s id ere d to be of value
in i n t e r p r e t i n g the gr owt h status of plants,
phase of t hei r development,

during a given

if these analyses w e r e

corre­

l a t e d w i t h the growth and devel opm ent of the plants*

If

the m a x i m u m p r o d u c t i o n of dry m a t t e r in dic ate d m e t a b o l i c
efficiency,

the c o m p o s i t i o n of the plants

m a x i m u m amount of dry m a t t e r could provide
the m o s t desirable

set of n ut r i t i o n a l

that p r o d u c e d the
some hint as to

conditions for b r i n g ­

ing about m a x i m u m p r o d u c t i o n of plant products.
A p p a r e n t l y c ert ain of the organic and mi ner al

c ons tit ­

uents ch a n g e d m a t e r i a l l y as a pert of the percent age
p o s i t i o n of the p l a n t d uring growth in response
mental

conditions

com­

to e n v i r o n ­

such as root temperature and con centration

77
of the n u t r i e n t

solution.

the n i t r o g e n - f r e e
to growth.

O f the o r g a n i c constituents,

ex tra ct

and p r o t e i n v a r i e d moo t in r e l a t i o n

There w a s also

consid era ble

ash and c e r t a i n a s h co n s t i t u e n t s
w eight pr o d u c t i o n .

variation in total

in r e l a t i o n to total dry

C e r t a i n co ns t i t u e n t s sh owe d a positive

c o r r el ati on w i t h gr owt h whi le others s howed a ne gat ive
correlation.

I n general there was no case whe re m a x i m u m

growth co uld be a s s o c i a t e d w i t h the m a x i m u m content of any
organic or m i n e r a l

component.

Apparently,

greatest e f f i c ­

iency in dry w e i g h t p r o d u c t i o n was a s s o c i a t e d w i t h c ertain
balances b e t w e e n organic and mineral
As a lr e a d y discussed,
w o u l d be us efu l
plant.
side,

such co rr e l a t i o n s

if consistent

in d e t e r m i n i n g n u t r i t i o n a l needs of the

If the b a l a n c e w e r e

st ro n g l y i n f a v o r of the organic

applic ati on s of n utr i e n t

However,

fractions.

salts w o u l d be indicated.

if n u t r i e n t element c o m p o s i t i o n were above the

m i n i m u m n e c e s s a r y for m a x i m u m dry we i g h t p r o d u c t i o n du rin g
a given p h y s i o l o g i c a l

age,

fur t h e r additions of nu tr i e n t

salts mi ght result in expenditure of reserve
materia ls.

If the supply of nu tr i e n t

carbohydrate

salts or if nut ri e n t

element c o m p o s i t i o n s hould be b e l o w the m i n i m u m r e q u i r e d
for m a x i m u m growth,

fu rt h e r additions of n utrient salts

might r esu lt In an acc u m u l a t i o n of reserve carbohydrate
material s»
A n a c c u m u l a t i o n of r es e r v e carbohydrate m ate ria ls w as
found to be a s s o c i a t e d w i t h depressions of growth r e s u l t i n g
from root temperatures.
tempera tur es

This indicates

that w h e n low root

restrict plant growth there m a y be an aocumu-

78

la t i o n of reserve

carbohydrates,

root t em p e r a t u r e s re st r i c t p l a n t

Conversely, when, hig h
growth there may be a

d e p l et ion of reserve carboh.ydra.tes,
The p h y s i o l o g i c a l
plant m a y reverse

such effects o f nutr ien t

t e m p e r atu re s upon the
ma ter i a l s .

age or stago of devel opm ent of the

a c c u m u l a t i o n of re serve c arb ohy dra te

I f the p l a n t was in the

development,

salts or root

stage of vegetati ve

the above r elationship m a y exist.

However,

if the p l a n t wa s in th e reproductive stage of development,
the above

relationship m a y be re ver sed .

SUMMARY
The influence of root temperature

and con centration

of the n utr ie nt solution on the growth and composition
of the R o b i n s o n s t r a w b e r r y wa s studied.

Root temperature

control was o b t a i n e d b y gro win g the plants in crocks of
sand p l u n g e d in temperature control tanks designed espec­
ially for this purpose.

C onc e n t r a t i o n of the nutrient

solution was m a i n t a i n e d by frequent renewal of sand cul­
tures w i t h various concentrations of H o a g l a n d 1s standard
nutrient solution.

Growth mea s u r e m e n t s were b a s e d on the

total p r o d u c t i o n of dry m a t t e r and the number of runner
plants produced.

Organic and nutrient-element composition

of the plant m a t e r i a l pro d u c e d was obtained by standard
analytical procedures.
During the vegetative p e r i o d of development,

the growth

of aerial por tions of the strawberry plant was closely
correlated w i t h root temperature.
was not pr ese nt for root growth.

Such a relationship
Therefore,

the top-

root ratio in cre a s e d as root temperature increased*
M a x i m u m dr y we ight accumulation in both root and aerial
portions of the strawberry plant o ccu rre d in nutrient
solutions of rel ati vel y lo w salt concentration (0,5> Hoagland* s s o l u t i o n ) 0

However,

concent rat ed solutions.

normal growth occurred in more

80
On the basis of dry we igh t accumulation, m a x i m u m growth
of all aerial parts of the plant during this vegetative
phase of development o ccu r r e d at root temperatures b etw een
65>° and 75>° F,

regardless of nutrient solution concentration.

There was no significant difference in dry we ight of roots
produced w i t h i n the range of root temperatures u s e d in
this study

to 75° F) > regardless of nutrient solution

concentration used*
A l t h o u g h root temperature h a d a pronou nce d effect on
the total growth of the aerial portions of the plant,

the

organic composition of the foliage was not significantly
altered b y differences in root temperature.

However,

there

were significant changes in the organic composition of the
roots w i t h changes in root temperature.
effects upon organic

The temperature

components appeared to be more or less

lo cal i z e d w i t h i n a given plant part.
Root temperature app eared to have very little,

if any,

appreciable effect on the nutrient-element composition of
the aerial portions of the plant during the vegetative
pe r i o d of development.

Total ash of the roots wa s

subject

to greater influence from root temperature differences than
was the f o l i a g e 0
The total, concentration of salts in the nutrient solution
h a d no appreciable affect on the percentage of crude fiber
and ether-extractable materials, but influenced the p ercent­
age of nitroge nou s and met abolizable carbohydrate
extract)

(N-free

components in both the le af and root tissue®

81

The concentration of salts in the nutrient solution
h a d a m ark ed affect on bot h the total ash content and
several of its components in both root and leaf tissueso
A significant negative correlation was f oun d to exist
between the metabolisable carbohydrate
and nitrogenous

(protein)

(N-free extract)

fractions in both the roots and

foliage of the strawberry at this stage of developmento
A significant negative correlation was also found to
exist between the content of ash and these metabolizable
carbohydrate fractions in both the roots and foliage*
same was true for these carbohydrate materials
component,

The

and the ash

potassium©

The possible influence of root temperature and of
’’l uxu ry” absorption of nutrient elements on the efficient
utilization of organic fractions and efficiency in dry
weight production was considered#

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Species differe nce s wi th re spect to
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Amer. J. Bot.
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Plant and soil w a t e r relationships.
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W a t e r rel at i o n s of
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Ve get a t i o n and
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S easonal changes in n i t r o g e n and carbo­
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H y d r a t i o n and growth.

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Mann, C. E. T. 1927*
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Effects of soil t emp era tur e on the
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Re lat ion of n u m b e r
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Proc. Amer. Soc.
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Effects of temperature on m e t a b o ­
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A m m o n i u m and nitrate n u t r i t i o n
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Bot. Gaz.

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Nightingale, G. T. 1935*
Effects of temperature on growth,
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Bob.
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Nitrate ana carbohydrate reserves
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Effects of
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The absorption by
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Amer. J. Bot. 33:107112.
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Proc, Amer. Soc.
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Pat hog eni cit y of C or ticiurn vagum on
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2 1 rl-i-59-1-1-82.

87

Richards, S. J*, Hagan, R. M., and Me Calla, T. M. 1952.
Soil temperature an d plant growth.
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Root studies. VTII® Apple root growth
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Studies of fall and spring applications
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R ela t i o n of leaf
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4

A PP E N D I X

90
T A B L E IX
EF FEC TS O F ROOT T E M P E R A T U R E A N D C O N C E N T R A T I O N OF THE
N U TR I E N T S OLU TIO N ON TH E P E R C E N T A G E DRY W E I G H T OF C E R T A I N
ORGANIC COM PON ENT S I N THE L E A V E S A N D R O O T S OF
RO BI N S O N S T R A W B E R R Y PLANTS
(A s umm ary of the s tatistical analysis is gi v e n in
Tables V and VI of the text)
Plant
p a rt

Root
temperature

(o F )

C o n c e n t r at i o n of H o a g l a n d 1s sol u t i o n
l.o" ”
0 o5
0.1

N i tr o g e n - f r e e E xt r a c t - %
Leaves

Roots

66 • 03

56.07
55.84

58.73
57.1+0
57.14-8
58.87

14-5.57
14-7.39
51.1+6
51.05

1+5.70
14-5.93
50.39
53.21

56.1+1+
60,50
65.63
63 . 7 5

16.88
17.44
17.63

17.00

12.31
13.31
12.19
14-91+

19.81

20.13
2 2 .1+14.

21.00
22.06

21.88
20.81

9.44
10.13

75
65
5#
45

57.14-3

75
65
55
45

56 .60

63.83
65.54
63.1+1

protein - %
Le aves

Roots

75
65
55
14-5
75
65
55
14-5

17.25

17.88
18.63
19.31
18.81

7.88
9.94

E t h e r Ext r a c t L eaves

Roots

75
65
55
14-5

1+-65

5o66

4.22

5.27
5.1i-3

5.29
5.15
5.32

4©26
5.05

75
65
55
14-5

2.31
1.78
l .65

2.45
2.32

2.01

1.22

2 1+4

2.09

2,35

5.oo

5.oi
3.50

2J+2

.

91

TABLE IX
Root
temperature
\° F)

C o n c e n t r a t i o n of Hoagland.’ s s o l u t i o n
1 ©0

0.5

H
O

Plant
part

GO NT •

1

Crude F i b e r -iJS
Leaves

75
65
55
14-5

10.64
10.96
10.17
10.26

10.19
9.90
10.22
10.22

10.49
10.33
9.99
9.69

Roots

75

19o55
1 8. 3 0
i4o74
11.97

1 9 o 46
17 .70
15.29
13.45

2 0 .88
1 8. 0 9
15.70
14.35

65
55
45

92

TABLE X
EF F E C T S OF ROOT T E M P E R A T U R E A N D C O N C E N T R A T I O N OF TH E
NU TR I E N T S OLU TIO N O N THE P E R C E N T A G E D R Y WETGHT O F TOTAL A S H
A N D C E R T A I N ASH C O M P O N E N T S I N THE L E A V E S AND R O O T S OF
R O B I N S O N STRAWBERRY PLANTS
(A summary of the st atistical analysis is g i v e n in
Tables VII a n d VIII of the text)
Plant
part

Root
temperature
(O p)

C o n c e n t r a t i o n of Hoagland. * s solution
1. 0
0.1
0.5
To tal Ash -

Le a v e s

75
65
55
45

10.03
9.56
9.86
9*16

8.54
9-97
9.52
8.59

6. 9 5
8.27
7.23
6 .9 5

Roots

75
65
55
45

1 3. 7 6
12*72
11*15
13 . 70

12.26
11.61
10.43
10.44

9.74
8.86
8.35
9.61

phosphorus - *
Le ave s

45

0.950
1.210
1.360
1.630

0.830
1.100
0.755
0.760

75
65
55
45

1.510
0.970
0.800
0.750

0.380
0.339
0 .2^4
0.288

0.210
0.165
0.183

2.09
2.11
2.09
2.03

75
65

55
Roots

Potassium -

O .440
0 .4 o 0
0.410
----

fo

Le a v e s

75
65
55
45

2.66
2.52
2.41
2.27

2.36
2.23
2.18
2.14

Roots

75
65
55
45

2.51
2.25
1*60
2.16

2.32
2.22
1.93
2.15

1.10
_ _ „

1.19
1.89

93

TABLE X
Pi ant
part

Root
temperature
(° F)

CONT.

C o n c e n t r a t i o n of Hoagland* s so lut ion
1.0

0.5

0.1

Ca l c i u m - %
Leaves

Roots

75
65
55
14-5

1.70
l o 45
1 .7 4
1.47

1.55
1.58
1.42
1.78

3.60
3.10
1.91

75
65
55
1+5

0.430
0 .1+70
0.360
0.150

0.100
0.130
0.160
0.150

w

0.588
0*660
0 .I+90

------

m » mm

0.120
0.160
0.100

M a g n e s i u m - fo
Leaves

75
65
55
45

0 .6 2 ?
0.527
0 . (94
0.603

0.14+6
0.31.3
O 0630
0 .780

Roots

75
65
55
45

0.1+84
O .316
0.61+5
0.700

0.580
O .630
0.663
0.620

mm mm mm

0.560
0 .368
0.1+85

Boron - %
Leaves

Roots

75
65
55
14-5

0.0185
0.0151
0 .0185
0.0158

0.0122
0 .0094
0.0107
0.0110

75
65
55
14-5

0.0026
0.0026
0.0029
0.0027

0.0017
0.0018
0.0022
0.0021

mm_

0.025
0.023
0.020
0.033

0.030
0.035
0.035

0.0069
0.0076
0 .0061+
-----

_m

0.0019
0.0020
0 .0011 >.

Iron - %
Leaves

75
65
55
14-5

0.017
0.018
0.021
0.019

94

TABLE X
Plant
part

Root
temperatur*

(° P)

CONT.

Concentration of Hoagland* s solution

1.0
Iron -

Roots

75
65
55
45

0 *500

0*800
0*600
0*900

Root s

75
65
55
45

1*430
0*695
0.391
0*668

75
65
55
45

0.063

0.1

0.800
0.800
o*5oo

0.800

%

Manganese Leaves

0.5

0.700

0.500
0.700

%
0.012
0.015
0.057
0.228

0*395

1.510
3.470

0.011

0 .061+
0 .081+

0.021
0 .011+

o.o 53

0.004

0*005
0*001
0.002

Copper Leaves

Root s

75
65
55
45

0.0004
0.0021
0.0010
0.0012

75
65
55
45

0.0002
0.0002

0.0001
0.0001

0.0007

0.0006
0.0008
0.0008
0.0001
0.0001
0.0001
0*0001

0.0004
0.0004
0.0005

0.0001
0.0001
0.0001