ABSTRACT

ORCHARD FACTORS AFFECTING THE INTERNAL BREAKDOWN
DISORDER OF 'JONATHAN' APPLES

BY

Robert L. Stebbins

The objective of this study was to identify those
factors in the orchard environment most closely related to
the incidence of internal breakdown of stored 'Jonathan'
apple fruit. Special emphasis was given to nutrition since
it is one of the environmental factors which can most easily
be altered both experimentally and by the fruit grower.
This thesis was prepared as a series of chapters each re-
porting a different subject area investigated in relation
to internal breakdown of 'Jonathan' apples. The title and
abstract of each chapter follows:

I. Physiological Disorders of 'Jonathan' Apple

Fruit Correlated with Nutrition and Other
Factors.

Results of mineral analysis of leaves and fruit
from each of 4 trees in 12 orchards were correlated with
incidence of internal breakdown, water core, lenticel spot,

and core browning of 'Jonathan' apples in two seasons.

Robert L. Stebbins

Fruit K and Ca were negatively correlated with breakdown
and water core in both years. Primarily in one orchard,
trees with high levels of Mn in leaves in 1969 produced
fruit with a high incidence of internal breakdown. Core
browning, which developed in CA storage, was negatively
correlated with leaf K, B, P, and Ca, and positively with
leaf N and fruit size.

II. Internal Breakdown of 'Jonathan‘ Apple Fruit
in Relation to Position on the Tree and Time
of Harvest.

Fruit samples were picked from the outer, middle
and inner zones of large, mature 'Jonathan' apple trees
from the northeast and southwest sectors on three dates.
The incidence of internal breakdown of stored fruit in-
creased with later maturity, and from inner to outer zones.
No significant differences were observed due to tree sector.
Fruit from the outer zone had significantly less K, P, Ca,
Mg, Cu, and B than fruit from the innermost zone, but
similar amounts of N.

III. The Effect of 2-chloroethylphosphonic Acid

(CEPA) on Red Color, Maturity and Internal
Breakdown of 'Jonared' Apples.

The application of 250 ppm 2-chloroethylphosphonic
acid to 'Jonared' apple trees on August 27, 1969 hastened
the development of red skin color. The effect on red color
was visible within 1 week of application, but with natural

color development treated fruits were indistinguishable

Robert L. Stebbins

from controls by October 3. Changes in ground color,
flesh firmness, weight loss in storage and incidence of
internal breakdown indicated that CEPA-treated fruit were
more mature. CEPA did not affect fruit size. CEPA fruit
could have been harvested commercially a week earlier be-
fore it had grown to a size which rendered it more sus-
ceptible to internal breakdown.

IV. Calcium-rich Crystals in Apple Trees and

Fruit.

Single crystals and clusters of crystals or druses
found by polarized light microscopy in tissues of Pyrus
malus L. were found to contain Ca, 0, and C using the
electron microprobe. Crystals, insoluble in 20% acetic
acid, were found in cells adjacent to the vascular tissues
near the pedicel in mature fruit and in dormant flower
buds, stems, petioles, shoot apex, roots and callus tissue.
Deposition of Ca as crystals may immobilize Ca and thereby
reduce the amount which would otherwise be translocated 1
into cortical cells of apple fruit which may result in an
increased incidence of internal breakdown due to low Ca
levels in those cells.

V. The Influence of Transpiration and Phloem

Transport on Accumulation of 45Ca in Apple
Leaves and Tomato Leaves and Fruit of Plants
Grown in Solution Culture.

Experiments were conducted to determine whether

45

the accumulation of Ca in apple seedlings, rooted layers

Robert L. Stebbins

of apple or tomato fruit is influenced by: (l) transpir-
ation rate, (2) phloem transport, (3) kinetin applications,
(4) age of leaf, and (5) length of one-year-old stem.

45 . . . . . .
Ca accumulation in leaves increased With increaSing rates

45 . .
Ca accumulation in leaves

of transpiration. The rate of
was inversely related to the length of the stem. Accumu-
lation of Ca in tomato fruit increased with increasing
transpiration rate of fruit relative to that of leaves as
determined in an experiment wherein either the fruit or

the entire plant was grown in a polyethylene bag. Although
young leaves accumulated 45Ca more rapidly, than old leaves,
no difference in the rate of transpiration between young
and old leaves was observed. More 45Ca accumulated in
mature leaves below rapidly-growing shoot tips than on
pruned shoots. Cytokinins had no effect on translocation

of 45

Ca into old leaves. Girdling experiments showed that
translocation of Ca was in the phloem. It is proposed that
Ca moves in the phloem and leaks into the xylem at increas-

ing rates as it approaches younger stem and growing apex.

ORCHARD FACTORS AFFECTING THE INTERNAL BREAKDOWN

DISORDER OF 'JONATHAN' APPLES

BY

Robert L. Stebbins

A THESIS

Submitted to
Michigan State University
in partial fulfillment of the requirements
for the degree of

DOCTOR OF PHILOSOPHY
Department of Horticulture

1970

ACKNOWLEDGMENTS

The author wishes to express his gratitude to
Dr. Donald Dewey for his patient assistance and guidance
during the course of this study. Acknowledgments are
also given to Dr. A. L. Kenworthy and Dr. Miklos Faust,
for their helpful advice and counsel. The author wishes
to thank Dr. Martin Bukovac for the use of laboratory

equipment.

ii

TABLE OF CONTENTS

Page
INTRODUCTION . . . . . . . . . . . . . 1
Chapter
I. PHYSIOLOGICAL DISORDERS OF 'JONATHAN'

APPLE FRUIT CORRELATED WITH NUTRITION AND

OTHER FACTORS . . . . . . . . . . 3

Abstract . . . . . . . . . 3

Materials and Methods . . . . . . . 5

Samples for Mineral Analysis . . . . 5
Tissue Preparation . . . . . . . 6
Mineral Analysis . . . . . . . . 6
Fruit Characteristics . . . . . . 7
Sampling for Storage. . . . . . . 9
Storage Conditions . . . . . . . 9
Statistical Procedure . . . . . . 10

Results. . . . . . . . . . . . 13

Fruit Size, Color and Finish vs.

Disorder. . . . . . . . . . . 13

Fruit Size, Color and Firmness vs.

Mineral Content . . . . . . . 24

Breakdown and Water Core Related to

Mineral Elements . . . . . . 26

Core Browning vs. Mineral Elements . . 38
Discussion. . . . . . . . . . . 38
Conclusions . . . . . . . . . . 50
Literature Cited. . . . . . . . . 52

iii

Chapter Page

II. INTERNAL BREAKDOWN OF 'JONATHAN' APPLE FRUIT
IN RELATION TO POSITION ON THE TREE AND TIME

OF MRVEST O O C O O O O O O O O O 5 6
Abstract . . . . . . . . . . . . 56
Materials and Methods. . . . . . . . 57
Results and Discussion . . . . . . . 59
Literature Cited . . . . . . . . . 65

III. THE EFFECT OF Z-CHLOROETHYLPHOSPHONIC ACID
(CEPA) ON RED COLOR, MATURITY AND INTERNAL

BREAKDOWN OF 'JONARED' APPLES. . . . . . 66
Abstract I I O I O O O O O O O O 66
Materials and Methods. . . . . . . . 67
Results and Discussion . . . . . . . 69
Literature Cited . . . . . . . . . 73

IV. CALCIUM-RICH CRYSTALS IN APPLE TREES AND

FRUIT. . . . . . . . . . . . . . 74
Abstract . . . . . . . . . . . . 74
Methods and Materials. . . . . . . . 76
Results . . . . . . . . . . . . 77
Discussion . . . . . . . . . . . 89
Literature Cited . . . . . . . . . 91

v. THE INFLUENCE OF TRANSPIRATION AND PHLOEM
TRANSPORT ON ACCUMULATION OF 45Ca IN APPLE
LEAVES AND IN TOMATO LEAVES AND FRUIT OF

PLANTS GROWN IN SOLUTION CULTURE. . . . . 93
Abstract . . . . . . . . . . . . 93
Materials and Methods. . . . . . . . 102

Transpiration Experiments. . . . . . 104
Girdling Experiments . . . . . . . 106
Cytokinin Experiments . . . . . . . 107
The Effect of Stem Length. . . . . . 108
Influence of Leaf Age . . . . . . . 109
Effect of the Growing Shoot Tip. . . . 110
Results 0 O O O O O O O I O I O 110
Transpiration Experiments. . . . . . 110
Girdling Experiments . . . . . . . 119
Effect of Stem Length . . . . . . . 138
Effect of the Young Growing Shoo Tip. . 142

iv

Chapter Page

Discussion . . . . . . . . . . . 147
Literature Cited . . . . . . . . . 152
APPENDIX C O O O O O O O O O O O O I 156

LIST OF TABLES

Table i Page

Chapter I

 

1. Cold Storage and Room Temperature Periods . . ll

2. Linear Correlations of Breakdown, Water Core
and Core Browning with Crop Load and Growth
Estimates in 1969 (r Values). . . . . . 14

3. Linear Correlations of Breakdown and Water
Core with Core Browning (r Values). . . . l7

4. Linear Correlations Between Fruit Size and
Incidence of Water Core, Breakdown and Core
Browning (r Values). . . . . . . . . 22

5. Highest Significant Correlations Between
Fruit Size, Color in September and Mineral
Content in June, 1968 Survey (r Values,
d.f. 46) . . . . . . . . . . . . 25

6. Mineral Content of Individual Sound and Break-
down Fruit of Similar Size, Each Pair from
the Same Tree. . . . . . . . . . . 26

7. Highest Significant Correlations Between
Breakdown, Water, Core, and Mineral Ele-
ments, (r Values) . . . . . . . . . 29

8. Highest Significant Correlations Between
Breakdown, Water Core, Core Browning and
Mineral Elements for Fruit from the Graham
Station (r Values, d.f. 10) . . . . . . 33

9. Highly Significant Multiple Correlations
Between Water Core and Mineral Content . . 34

vi

Table

10.

ll.

12.

Page

Highly Significant Multiple Correlations
Between Breakdown (BD) and Mineral Content . 35

Highly Significant Multiple Correlations

Between Breakdown and Mineral Elements,

Graham Station Samples. . . . . . . . 41
Highly Significant Multiple Correlations Be-

tween Core Browning and Mineral Elements. . 11

Chapter II

 

Mean Percentage of 'Jonathan' Apples with
Internal Breakdown After Storage According
to Date of Harvest and Location on the
Tree, 1968. . . . . . . . . . . . 60

Mean Weight (Grams) of 'Jonathan' Apples
According to Date of Harvest and Location
on the Tree . . . . . . . . . . . 60

Ground Color of 'Jonathan' Apples (Ditton
Laboratory Green-Yellow Color Charts, 5 =
Green, 6 = Greenish Yellow) at Harvest
According to Date of Harvest and Location
on the Tree . . . . . . . . . . . 62

Flesh Firmness of 'Jonathan‘ Apples (Pounds)

at Harvest According to Date of Harvest

and Location on the Tree . . . . . . . 62
Mineral Content of 'Jonathan' Apple Fruits

According to Location on the Tree . . . . 63

Chapter III

 

Effect of a 250 ppm Foliar Spray of CEPA
on Mean Values of Several Characteristics
of Harvested 'Jonathan' Apples . . . . . 70

vii

Table Page

Chapter V

 

1. Effect of Conditions Within Polyethylene
Bags on Translocation of 5Ca to Leaves
of Apple Seedlings (Counts Per Minute Per
100 mg Dry Weight of Leaf) . . . . . . 115

2. Effect of Girdling and Conditions in a
Polyethylene Bag on Ca Content (Percent Dry
Weight) of Tomato Fruits. . . . . . . 115

3. Effect of Conditions in a Polyethylene Bag
on Mineral Element Content of Tomato
Leaves. . . . . . . . . . . . . 116

4. Effect of Vapor Pressure Deficit (VPD) on
Transpiration of Apple Trees in Solution
CUlture . O O O O O O O O O O O 116

5. Effect of Stem Girdling on Assimilation of
45Ca by Apple Seedlings in Solution Cul-
ture (Counts Per Minute Per 100 mg Dry
Weight of Leaf). . . . . . . . . . 124

6. Effect of Girdling, Leaves Below the Girdle

and Cutting the Rooted Layer, on Absorption

and Translocation of 45Ca by Apple Plants

in Solution Culture . . . . . . . . 130
7. Effect Of Girdling on Accumulation of 45Ca

in Phloem of Apple (Counts Per Minute Per

100 mg Dry Bark) . . . . . . . . . 133

8. The Effect of the Length of One-Year-Old
Stem on the Rate of Translocation of 45Ca
to Leaves of Apple Seedlings (Counts Per
Minute Per 100 mg Dry Weight of Leaf
After 8 Days) . . . . . . . . . . 141

9. Accumulation of 45Ca by Phloem and Xylem of
Apple Seedlings in Solution Culture
(Counts Per Minute Per 100 mg Dry Tissue) . 141

10. Transpiration Rate by Upper vs. Lower
Leaves of Apple. . . . . . . . . . 142

viii

Table Page

11. The Effect of the Presence of a Rapidly-
Growing Shoot Tip on 45Ca Absorption of
Fully-Expanded Leaves Below (Counts Per
Minute Per Total Dry Weight of Leaves).
The Results Are for Non-Pruned and
Pruned Shoots on the Same Plant . . . . . 147

Appendix

A-l. Mineral Content of Jonathan Leaves (July
Samples). . . . . . . . . . . . . 156

A-2. Mineral Content of Leaves (July Samples) and
Incidence of Water Core and Internal Break-
down in Fruit After Storage, 1969 Survey . . 157

A-3. Mineral Content Of Cortical Tissue Of Fruit
(September Samples), 1969 Survey. . . . . 159

A-4. Mineral Content of Leaves (June Samples) and
Incidence of Water Core and Internal Break-
down in Fruit After Storage, 1968 Survey . . 161

A-5. Mineral Content of Fruit (Including Peel and
Core), 1968 Survey . . . . . . . . . 163

ix

Figure

LIST OF FIGURES

Chapter I

 

Correlation Between Water Core and Breakdown,
1969 Survey, Second Harvest. Each Point
Represents the Mean of 50 Fruit . . . .

Correlation Between Mean Fruit Weight and
Breakdown, 1969 Survey . . . . . . .

Correlation Between Fruit Diameter and Core
Browning, 1969 Survey, Second Harvest from
CA Storage. Each Point Represents the Mean
of 50 Fruit. . . . . . . . . . .

Correlation Between Water Core and Leaf Mn
(ppm) from 1969 Survey First Harvest,
September Leaves . . . . . . . . .

Correlation Between Water Core from 1969
Survey of First Harvest, and K in September
Fruit. . O O O O O I O O O C O

Severity of Internal Breakdown as Related to
the Ca Level of Smaller-Than-Average (S, A)
and Larger Than Average (L, A) Fruit in the
1968 Survey, June Samples . . . . . .

Percent Breakdown in Samples from the 1968
Survey as Related to the Ca Level of Fruit
with (A, 0) Less Than Average and (B, 0)
More Than Average Mg Content . . . . .

Page

16

19

21

28

31

37

40

Figure Page

Chapter IV

 

1. Crystals in Small Cells Adjacent to Vascular
Bundles Near the Pedicel of a Mature Apple
With Internal Breakdown: Left, Reverse
Sample Current Oscillogram; Middle, Ca
X-Ray Distribution Oscillogram; Right,
Reverse Sample Current Oscillogram . . . . 79

2. Crystals in Cross Section of Dormant Apple
Flower Bud: Left, Reverse Sample Current
Oscillogram Showing Part of Two Florets;
Middle, Enlargement of Center Portion;
Right, Ca X-Ray Distribution . . . . . . 82

3. Ca Crystals in Bark of Apple Shoots of the
Previous Season's Growth: Left, Reverse
Sample Current Oscillogram, Periderm on
Left (P); Middle, Enlargement of Right
Center Portion; Right, Ca X-Ray Distribution. 84

4. Ca Druses in Bark at Apex of Apple Seedling:
Left, Reverse Sample Current Oscillogram;
Middle, Ca X-Ray Distribution; Right, a
Typical Druse . . . . . . . . . . . 86

5. Ca Crystals in Bark from an Old Apple Limb;
Left, Reverse Sample Current Oscillogram;

Right, Ca X—Ray Distribution . . . . . . 88
6. Ca X-Ray Distribution in Petiolar Xylem (Left)
and Phloem (Right) . . . . . . . . . 88
Chapter V

 

1. An Autoradiogragh Showing Restricted Trans-
location of 4 Ca by Conditions Within a
Polyethylene Bag Compared with Lower Leaves
Outside the Bag . . . . . . . . . . 112

2. Leaf Temperatures of Trees in Humid vs. Dry
Air Compared with Air Temperature; (a) Air
Temperature in Bag, (b) Leaves in Humid
Air, (c) Leaves in Dry Air. . . . . . . 114

3. Regression Between 45Ca Accumulated in Leaves
and Water Loss by Apple Trees. . . . . . 118

xi

Figure

4.

100

11.

Difference in Vapor Pressure Deficit Between
(a) Bags with Moving Humid or Dry Air and
(b) Plant in Still Air in Polyethylene
Bag and Greenhouse . . . . . . . .

Vapor Pressure Deficits in Polyethylene Bags
with Moving (a) Humid Air, (b) Dry Air and
(c) in the Greenhouse . . . . . . .

Blockage of 45Ca Movement by a Girdle in the
One-Year-Old Stem of an Apple Seedling as
Shown by the Lack of an Autoradiographic

Image of Leaves from a Girdled Tree. Auto-
radiographs of Slices of Wood and Bark from

the One-Year-Old Stem Above and Below the

Girdle Show a Lack of 45Ca in the Center of

the Xylem . . . . . . . . . . .

Illustration of the Treatment of Rooted Apple
Layers in an Experiment to Determine (1) If

Ca Would Pass a Girdle if it Had Access to
the Xylem and (2) If Lack of Translocation
Past a Girdle was Due to Root Starvation.

Accumulation of 45Ca in Lower Leaves of
Rooted Apple Layers: (a) Intact Control

Plants and (b) With a Fresh Cut at the Base

of the Layer Allowing Access of the

Nutrient Solution to the Xylem. Leaf Discs

were Punched at 24 Hour Intervals, ph =
Phloem Sample. . . . . . . . . .

45

Translocation of Ca Into Strips of Phloem

of 'MM 106' Apple Layers Separated from the

Xylem by Cellulose Film. The Highest
Fully-Expanded Leaf Was Also Autoradio-
graphed to Indicate That Absorption and

Translocation Had Taken Place in the Plant.

Left: Leaves and Phloem Strips. Right:
Autoradiograph . . . . . . . . .

Movement of 45

and Transferral to Non-radioactive Medium

Autoradiograph of Strips of Phloem from an

Apple Seedling Showing the Presence of 45Ca
Which was Translocated from the Leaf Lamina

During Leaf Senescence. . . . . . .

xii

Ca from Vascular Tissues of the
Old Stem of an Apple Seedling Into Regrowth
After Removal of the Current Season's Shoot

Page

121

123

126

129

132

135

137

140

Figure Page

12. Correlation Between Leaf Surface Area Per
'MM 106' Apple Layer and Water Used Over a
3 Day Period . . . . . . . . . . . 144

13. Accumulation of 45Ca by Leaves of Varying Age

on a Single Apple Seedling. Left, Young
Leaves; Right, Old Leaves. . . . . . . 146

xiii

INTRODUCTION

The objective of this study was to identify those
factors in the orchard environment most closely related
to the incidence of internal breakdown of stored 'Jonathan'
apple fruit. Special emphasis was given to nutrition
since it is one of the environmental factors which can
most easily be altered both experimentally and by the
fruit grower. Calcium was given special attention since
physiological disorders of apples in storage have often
been associated with low Ca levels in the fruit. Further-
more, there is a considerable amount of evidence in the
literature indicating that treatment with Ca often fails
to completely prevent disorders which have been
associated with Ca deficiency. A need was seen for more
fundamental knowledge concerning factors that influence
fruit Ca levels. I

This thesis was prepared as a series of chapters,
each reporting a different subject area investigated in
relation to internal breakdown of 'Jonathan' apples.

The title of each chapter follows:

II.

III.

IV.

Physiological Disorders of ‘Jonathan' Apple
Fruit Correlated with Nutrition and Other
Factors.

Internal Breakdown of 'Jonathan‘ Apple Fruit in
Relation to Position on the Tree and Time of
Harvest.

The Effect of 2-chloroethy1phosphonic Acid
(CEPA) on Red Color, Maturity and Internal
Breakdown of 'Jonared' Apples.

Calcium-rich Crystals in Apple Trees and
Fruit.

The Influence of Transpiration and Phloem

Transport on Accumulation of 45

Ca in Apple
Leaves and Tomato Leaves and Fruit of Plants

Grown in Solution Culture.

CHAPTER I

PHYSIOLOGICAL DISORDERS OF 'JONATHAN' APPLE FRUIT

CORRELATED WITH NUTRITION AND OTHER FACTORS

Robert L. Stebbins

Michigan State University

Abstract. Results of mineral analysis of leaves and
fruit from each of 4 trees in 12 orchards were correlated
with incidence of internal breakdown, water core,
lenticel spot, and core browning of 'Jonathan' apples in
two seasons. Fruit K and Ca were negatively correlated
with breakdown and water core in both years. Primarily
in one orchard, trees with high levels of Mn in leaves

in 1969 produced fruit with a high incidence of internal
breakdown. Core browning, which developed in CA storage,
was negatively correlated with leaf K, B, P and Ca, and

positively with leaf N and fruit size.

Internal breakdown of fruit in storage occurs with
the 'Jonathan' apple variety grown in the USA, Japan,
New Zealand, and Europe (6, 7, 21, 34). The disorder
appears usually after several months of cold storage

followed by a short period at elevated temperatures (5).
3

The first symptoms are a softening of the flesh near the
calyx end and the appearance of brown color in vascular
elements and surrounding cortical tissue (7). The browning
and softening spreads to the extent that the fruit becomes
worthless.

The incidence of breakdown may vary considerably
between seasons (22). Within any given season it may vary
greatly between orchards and between trees within orchards
(22). Due to this large and unpredictable variability,
consistent results are difficult to obtain in field
experiments with treatments which might reduce the
incidence of breakdown.

In a survey of 'Jonathan' orchards in Michigan by
Buneman gt 31. (5), a negative correlation between levels
of K and internal breakdown of 'Jonathan' apples was
found. Further study Of Michigan orchards, which is the
substance of this report, was undertaken with the following
objectives: (1) to confirm or refute the limited results
obtained by Buneman et_al.; (2) to determine if nutrients
in addition to K are correlated with internal breakdown;
(3) to discover correlations which would lead to logical
hypotheses regarding the cause Of breakdown and,
cbnsequently, remedial treatment; and (4) to locate
orchards with a history of internal breakdown that could

serve for future experimentation on this problem.

MATERIALS AND METHODS

Four orchards in each of 2 central Michigan districts,
near Sparta and Belding and 4 in southwest Michigan near
Hartford were selected for the survey. Normally, fruit
matures about a week earlier in the Hartford district than
in the central area. All orchards were non—irrigated with
the trees growing in sod on seedling roots. Originally,
10 trees in each orchard were selected for sampling. From
the original 10, 4 trees were selected as representative
according to leaf analysis in 1968. These trees were
marked and used for all subsequent sampling. The trees
were 20 to 40 years Old and typical of others in the orchard.
Terminal growth of the limbs varied from 2—4 inches in some
orchards to 2—3 feet in others. Pruning practices and
tree spacings also varied considerably.

In addition to the 12 orchards, 12 trees on the
Michigan State University Graham Experiment Station,
Grand Rapids, were sampled. These trees were smaller than
trees employed in the survey, being 10 years old.

Samples for mineral analysis. A leaf sample

 

consisted Of 25 leaves including petioles from the middle
of current season's terminal shoots at about head height.
One sample was collected from each tree at each sampling.
Leaves were taken from shoots of average length on all

sides of the tree. Five sets of leaf samples were picked

from survey trees on the following dates: in 1968, June 14,

July 22 or 23, September 12; in 1968, July 16 or 17

and September 12 or 13. Samples of 25 fruits were

picked from similar locations on each tree in 1968

on June 14 and September 12 and in 1969 on July 16 or 17
and September 13 or 14. Trees at the Graham Station

were sampled on the same dates as the survey trees in 1968
and on July 17, 1969.

Tissue preparation. Leaves were dried 24 hours in

 

a forced-air oven at 60°C, then ground in a Wiley mill.
Whole immature fruits were diced, dried and ground in
June and July 1968. In September, 2 sections, including
peel and core were cut from Opposite sides of the fruit
after the method of Perring (27), diced and dried. Since
internal breakdown is confined to the cortex, one might
expect closer correlations between mineral content of
samples consisting only Of that tissue. For this reason,
in 1968, July fruit samples were cored and September
samples were peeled and cored before drying.

Pairs of fruit for mineral analysis of the same
size were selected from the same sample in the 1969
survey after storage in which one fruit was sound and
the other showed internal breakdown.

Mineral analysis. N was measured by the macro—

 

Kjeldahl method and K, following extraction with water,
by flame spectrophotometry. Levels Of P, Na, Ca, Mg,

Mn, Fe, Cu, B, Zn and Al were determined using

photoelectric spectrometry. Ca was also measured by

atomic absorption spectrOphotometry. Fruit samples taken
in 1969 were concentrated eight-fold for photoelectric
spectrometry in order to more accurately measure the small
quantities of elements present in fruit flesh. In addition,
sensitivity of the Ca scale on the spectrometer read—out
console was attenuated to twice normal.

Fruit characteristics. The diameter of 25 fruit

 

per tree was measured on the dates of leaf sampling. The
diameter of each stored fruit of the first samples examined
in 1968 was measured. Samples were weighed in 1969.

The mean length of current season's terminal shoots
was estimated visually at harvest time. A ruler was used
to measure a few shoots on each tree to verify estimates.

Crop was estimated visually and noted on a scale,

where 1 very light crop, 2 = moderately light, 3 = full

crOp, 4 moderately heavy, and 5 = extremely heavy.

Flesh firmness was measured using a U. S. fruit
pressure tester with a 7/16 inch tip and recorded as
pounds. Fruits tested were 2.40 to 2.75 inches in
diameter. Two measurements were taken from peeled portions
on opposite sides of each of 10 fruit. Flesh firmness was
measured before and after storage in 1968, and before
storage in 1969.

Weight loss in storage was determined for samples

consisting of 10 fruits between 2.5 and 2.75 inches

diameter in 1969. The samples were weighed to the nearest
gram before and after storage and after two weeks at room
temperature. They were stored in paper bags on wire racks
to permit good air circulation to all lots.

Ground color was determined by visual comparison
with Ditton laboratory green-yellow apple and pear color
charts, and numerically rated as 4 = green and 8 = yellow.
Red color was estimated on a scale of 1 = none, 2 = very
little, 3 = 50% of skin colored, 4 = 75% of skin colored,
5 = 95% of skin colored. Color was determined for each
of the 50 fruit in a sample and averaged.

Severity of surface russeting was rated as follows:
1 = none, 2 = moderate, 3 = severe. Presence or absence
of lenticel spots was also noted. Internal breakdown,
core browning and water core were detected by cutting
near the calyx end and at the equator. Number of fruit
with these disorders was recorded. Severity of breakdown
was rated as l = none, 2 = slight, 3 = moderate, 4 = severe
or 5 = total. Subsamples of 10 fruit were examined for
water core before storage. The number Of fruits, in a
50-fruit sample, showing core browning with varying degrees
of severity was recorded as follows in 1968: l = none,

2 = questionable, and 3 = definite core browning. The
incidence of core browning of any severity was recorded

in 1969.

Sampling for storage. Fruit was sampled from the

 

outer and middle zones Of foliage whenever possible and
from all sides of the tree. One bushel per tree was

picked on the first harvest date. On the second date 2
bushels were picked, one for storage in air, the other for
controlled atmosphere storage. Dates of harvest were as
follows: in 1968, Hartford area September 24 and October 3,
central areas, September 28 and October 7; in 1969, Hart-
ford area October 3 and October 16, central area October 9
and October 21 and 23. Samples from the Graham Station
were picked October 10, 1968 and October 9, 1969.

The crOp was too light on trees marked for the
survey to obtain a complete sample from one orchard near
Hartford in 1969. Fruits were picked from other trees in
the block to complete the sample. The second sampling was
lost from 2 orchards in 1969 because the grower harvested
the plots before the second date of pick.

All samples were collected and stored in wooden
field crates of l bushel capacity. They were placed in
storage on the day Of harvest.

Storage conditions. Survey fruit samples were

stored in air at 38°F or in 3% O2 and 5% CO at 32° F

2

in 1968. In 1969, samples were stored in air at 38°F or

in 11% O and 10% CO at 32°F. Samples from the Graham

2 2
Station were stored in 3% O2 and 5% CO2 at 38° F in 1968

and in air at 38°F in 1969. Controlled atmospheres were

10

established within a week after the final harvest. As
shown in Table 1, survey samples were removed for
examination twice except for the CA samples in 1969. The
latter were removed once, examined upon removal and again
after 2 weeks at 60 to 70°F. Subsamples of 50 fruit were
placed in polyethylene box liners after removal from
storage and held at 70°F for 2 weeks before examination.
Samples from the Graham Station were examined only once.

Statistical procedure. Simple linear correlations

 

between all variables using the means of 50-fruit samples
were calculated on the CDC 3600 computer. For the first
harvest in 1968, correlations were obtained between the
characteristics other than mineral content, Of the 50
individual fruit fruit from each tree. The physiological
disorders of fruit were treated as dependent variables.
Multiple correlation coefficients were Obtained with
least squares and least squares delete programs. Mineral
analysis values from leaf and fruit samples were trans-
formed to the second, third and fourth power and log base
10. Simple linear correlations and least squares delete
problems were computed to select the transformed variables
most closely correlated with breakdown. Multiple
correlations were selected for presentation which, in
general, met the criteria stated below:

1. All partial correlations for independent

variables significant at 0.05 or less.

TABLE 1 .

11

Cold storage and room temperature periods.

 

 

Sample and type Date Months of Days at
of storage Examined Storage 70°F
Survey, air 12/28/68 2 1/2 12
Survey, air 2/25 to 3/1/69a 4 1/2 12
Survey, CA 3/18/69 5 14
Survey, CA 4/22/69b 6 1/2 3
5/7/69 7 18
Graham Sta.,CA 6/17/69 8 14
Survey, air 12/15, 16, 17/69a 2 10
Survey, air 2/19/70 4 14
Survey, CA 3/23/70 5 14
Survey, CA 4/6/70 6 14
Graham Sta., air 2/12/70 4 14

 

aSamples not examined were returned to 32°F until

examined.
b

second date.

Twenty-five fruit were examined,

50 fruit on the

12

2. No more than 5 independent variables involved.

Although a larger number of variables may

account for more of the variation of the

dependent variable, each independent variable

accounts for a smaller percent of the variation

and is, therefore, less meaningful.

3. All independent variables must logically be

candidates for a cause and effect relationship

hypothesis with the dependent variable. Of

course, no matter how high the R value is,

multiple or simple correlations do not establish

a cause-and-effect relationship.

4. The R must be above the following minimum values

unless it has special interest: 2 independent

variables, 0.50; 3 variables, 0.60; 4 variables,

0.66; 5 variables, 0.74. This criterion was

used to reduce the number of multiple
tions reported for those most closely
with the dependent variable.

All correlations reported are significant

level or higher. Correlations with the Opposite

correla—

associated

at the 5%

sign in

either year when compared with the same two factors

correlated in the other year, were not reported.

13

RESULTS

The incidence of internal breakdown in 1968 was
unusually low. Of the 9,600 fruits examined after
storage, only 5% had breakdown. In 1969, 12.3% of the
fruit from the first harvest had breakdown and some samples
showed more than 90% breakdown. The trees which produced
fruit with a high incidence of breakdown in 1969 were not
the same ones with the most breakdown in 1968. Fruit from
light-cropping trees were prone to breakdown and water
core (Table 2). Estimated shoot length was also negatively
correlated with water core. A strong positive correlation
was found between internal breakdown and water core in the
1969 survey (Fig. l). The incidence of core browning
increased with the incidence of water core (Table 3) but
the relationship was not as close as that between water
core and breakdown (Fig. l). The number of fruit with
lenticel spot was correlated with core browning in 1969,

r = 0.49**.

Fruit size, color and finish vs disorder. The incidence

 

of internal breakdown, water core and internal browning
increased with increasing fruit size (Fig. 2 and 3; Table 4).
In fruit from the first harvest in 1969, the incidence of
breakdown increased with increasing fruit size, firmness

at harvest and weight loss during the room temperature
period after storage (R = 0.86**). Among samples from the

Graham Station in 1969, the incidence of breakdown

14

TABLE 2. Linear correlations of breakdown, water core
and core browning with crOp load and growth
estimates in 1969 (r values).

 

Disorder Crop load Shoot length

 

Survey (d.f. 41)

Internal breakdown n.s. n.s.
Water core —0.31* -0.67**
Core browning n.s. 0.51**

 

Graham Station (d.f. 10)

Internal breakdown -0.63* n.s.
Water core -0.74** —0.64*
Core browning n.s. n.s.

 

*Significant at the 5% level.
**Significant at the 1% level.

Fig.

l.

15

Correlation between water core and
breakdown, 1969 survey, second harvest.
Each point represents the mean of 50
fruit. [**Significant at the 1% level.]

1" R .‘2'

(%J

BREAKDOWN

100

50

 

16

 

/‘
/
l
/
/ .
/
/
/
/
/ o
/
/
. /.
/
l
,/
F //
/
/
/°
,/
z/ y: 2.43 +1.05.
/ XX
0 l' =0-97
'4
,1}.
We
0 50 100

WATERCORE (‘70)

17

TABLE 3. Linear correlations of breakdown and water core
with core browning (r values).

 

 

 

 

Disorder Core Browning
Survey 1968 Survey 1969
(d.f.46) (d.f. 38)
Internal breakdown 0.48** 0.34*
Water core n.s. n.s.

 

Graham Station
(d.f. 10)

Internal breakdown n.s. n.s.

Water core 0.68* a

 

*Significant at the 5% level.
**Significant at the 1% level.

aNo core browning occurred in 1969 samples.

18

Fig. 2. Correlation between mean fruit weight
and breakdown, 1969 survey. [**Signifi-
cant at the 1% level.]

BREAKDOWN (i)

40

U
0

N
0

d
O

 

19

Y= '27.6 *O.36X
it

r=0.45

 

 

80 100
FRUIT WEIGHT (9)

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TZXBLE4. Linear correlations between fruit size and
incidence of water core, breakdown and core
browning (r values).

Disorder Fruit size
Survey 1968 Survey 1969

(d.f. 46) (d.f. 38)
IInternal breakdown 0.46** 0.34*
(Sore browning 0.40** 0.56**

Graham Station
(d.f. 10)

Internal breakdown 0.58* n.s.
‘Water core 0.63* n.s.

*Significant at the 5% level.
**Significant at the 1% level.

23

decreased with increasing amounts of surface russeting

and weight loss during the room temperature period after
storage (R = 0.86**). Among samples from the Graham
Station in 1969, the incidence of breakdown decreased
with increasing amounts of surface russeting and weight
loss in cold storage (R = 0.82**). In another multiple
correlation, the incidence of breakdown decreased with
heavy cropping and skin russeting but increased with

fruit size and a high percent moisture in fruit samples

in July (R = 0.92**). When cutting the fruit, it was noted
that the area of breakdown was associated with the non-
russeted side of a russeted fruit. In 1968, russeting
was negatively correlated (r = -0.38**) with increase

in fruit diameter between mid—August and mid—September.
Within fruit samples from individual trees, russeting

was negatively associated with yellow ground color

(r = —0.59**), and red over-color (r = —0.48**). Russeting
was usually associated with small fruit size, but in one
orchard the opposite relationship occurred. The incidence
of internal breakdown and water core increased with
increasing red and yellow skin color.

Among the samples from the 1969 survey, the
incidence of lenticel spots decreased with increasing
yellow ground color but increased with heavy cropping and
weight loss in storage (R = 0.77**). Weight loss in
storage increased with increasing incidence of lenticel

spots (r = 0.60**).

24

Fruit size, color and firmness vs. mineral content.

 

In general, fruit size increased and red color
decreased with increased leaf mineral content (Table 5).
The trend was Opposite with respect to leaf P. Increasing
fruit size was associated with decreasing fruit P, Ca,

Mg, and Mn but with increasing with fruit Cu, Zn and Al.
Yellow ground color increased with increasing fruit P, Ca,
Mg and Mn. In 1968, fruit K was negatively correlated
with red color, r = -0.34*. In general, however, K levels
were not correlated with fruit size or color.

In 1968, but not in 1969, fruit firmness at harvest
was negatively correlated with leaf N, Ca, Zn and Al
(r = -0.77**, -0.50**, -0.42**, -0.41**, respectively).

In 1968, firmness increased with increasing fruit Ca levels
(r = -.30*). Samples of fruit with more yellow ground
color and more red color tended to lose firmness in storage
more rapidly than less well colored fruit in 1968

(r = 0.47**, 0.52**, respectively). Core browning in 1968
decreased with increasing fruit firmness (r = -0.30*).

In 1969, firmness at harvest was negatively correlated with
internal breakdown, water core, fruit size, and leaf Mn

(r = -0.36*, -0.30*, -0.4l**, —0.35*, respectively).
Firmness increased with increasing fruit K and leaf Zn and

Al (r = 0.38**, 0.30*, and 0.35*, respectively).

25

TABLE 5. Highest significant correlations between fruit
size, color in September and mineral content
in June, 1968 survey (r values, d.f. 46).

 

Fruit Characteristic

 

 

 

 

 

 

Element
Red Ground Red Ground
Diameter Color Color Diameter Color Color
June leaves June fruit
N 0.62** -0.59** -0.64** n.s. n.s. n.s.
P -0.78** n.s. 0.60** —0.68** n.s. 0.47**
Na 0.74** n.s. n.s. n.s. n.s. n.s.
Ca 0.59** —0.58** —0.57** -0.39** n.s. 0.43**
Mg 0.48** n.s. —0.51** -0.56** n.s. 0.34*
Cu 0.54** —0.56** —0.55** 0.34* -0.47**—0.31*
Al 0.60** n.s. -0.43** 0.61** —0.66**-0.66**
K n.s. n.s. n.s. —0.32* n.s. n.s.
Mn n.s. n.s. n.s. -0.36* n.s. 0.34*
Zn n.s. n.s. n.s. 0.65** -0.37* -0.46**
July leaves September fruit
N n.s. n.s. n.s. 0.34* -0.40**-0.49**
K n.s. n.s. 0.31* n.s. —0.29* n.s.
September leaves

 

Cu 0.40** —0.66** -0.64** n.s. n.s. n.s.

 

*Significant at the 5% level.
**Significant at the 1% level.

26

Breakdown and water core related to mineral elements.

 

Analysis of the cortical tissue of pairs of individual
fruits of approximately equal size but one sound and the
other with breakdown shows a tendency for fruit with
breakdown to be lower in Ca, Fe, and Zn and higher in P,

Mg, and B than sound fruit (Table 6).

TABLE 6. Mineral content of individual sound and break-
down fruit of similar size, each pair from the
same tree.a

 

 

Element Element
(%) Sound Breakdown (ppm) Sound Breakdown
P 0.099 0.112 Fe 22.5 13.8
Ca 0.0381 0.0284 B 30.4 36.2
Mg 0.0249 0.0282 Zn 13.39 9.25

 

 

aLevels of N, K, Na, Mn, and A1 showed no trend
related to breakdown or sound fruit.

The highest correlation found between a mineral element
and a physiological disorder was leaf manganese with water
core in 1969 (Fig. 4). This relationship was primarily a
result of high, 234—317 ppm, Mn levels in one orchard in
1969. The most consistent relationships were the negative
correlations between fruit or leaf K and breakdown (Table 7)
and water core (Fig. 5). In 1968, however, leaf K at the

Graham Station was positively correlated with breakdown

27

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TABLE 7. Highest significant correlations between break—
down, water, core, and mineral elements,
(r values).
Surveyil968 d.f. 46 Survey 1969 d.f. 41
Element break— water core break- water core
down core browning down core browning
Fruit Fruit
N 0.39** n.s. 0.39** 0.36 n.s. 0.43
P -0.36* n.s. —0.45** -0.33 n.s. n.s
Na n.s. 0.32* n.s. n.s. n.s. n.s.
K -0.46** -O.30* —0.50** -0.50** -0.56** n.s.
Ca —0.39** n.s. —0.34* —0.35* n.s. —0.40**
Mn n.s. n.s. n.s. 0.34* 0.31* n.s.
Leaves Leaves
N a -0.37** 0.40** a n.s. 0.53**
P -0.31* n.s. -0.46** n.s. n.s. -0.40**
K —0.37** n.s. -0.56** —0.46** —0.51** —0.37*
Ca -O.32* -0.32* n.s. —0.32* n.s. n.s
Mg 0.54** n.s. a n.s. n.s. a
Cu -0.31* n.s. n.s. —0.34 n.s. n.s.
Fe -0.36* n.s. 0.4l** n.s. n.s. n.s.
Zn -0.31* n.s. n.s n.s. n.s. -0.3l*
Mn n.s. n.s. n.s. 0.80** 0.94** n.s.
B n.s. n.s. —0.29* —0.49** -0.46** n.s
*Significant at the 5% level.
**Significant at the 1% level.
aCorrelations significant but with opposite signs
in the two years.

Fig.

30

Correlation between water core from

1969 survey of first harvest, and K

in September fruit. [**Significant at
the 1% level.]

WATER CORE (%)

80

60

 

31

Y=40 -55x
*t
r=0.56

 

l O.
0.4 0.6 0.8
FRUIT KIfl)

32

(Table 8). Both fruit and leaf Ca had a consistently
negative correlation with breakdown in the fruit from
the survey and the Graham Station. Correlations with
other elements were less consistent, sometimes being
significant with the opposite sign in the second year.
At the Graham Station, both fruit and leaf Ca were
negatively correlated with breakdown and water core
(Table 8). Leaf Ca, but not fruit Ca, was negatively
correlated with breakdown in 1969 (Table 8). Water core
and breakdown increased with increasing leaf B but
decreased with increasing fruit B. Multiple correlations
between breakdown or water core and B and Ca (Table 9, 10)
also show the Opposite Sign for leaf B, as opposed to
fruit B.

In both 1968 and 1969, multiple correlations
obtained using the least squares delete program showed
fruit K and Ca to be the most closely negatively related
elements to internal breakdown (Tables 10 and 11). The
The incidence of breakdown (weighted for severity) in
larger-than-average sized apples increased more rapidly
with decreasing fruit Ca levels than did the incidence
of breakdown (weighted for severity) in smaller-than-
average sized fruit (Fig. 6). In 1968, fruit Mg and P
were most closely positively associated with breakdown.
The incidence of breakdown in fruit with higher-than-

average Mg levels decreased more rapidly with increasing

33

TABLE 8. Highest significant correlations between break-
down, water core, core browning and mineral
elements for fruit from the Graham Station
(r values, d.f. 10).

 

 

 

 

1968 1969
Element break- water core break- water
down core browning down core
Leaf
N n.s. -0.81** n.s. n.s. n.s.
P n.s. n.s. n.s. n.s. 0.62*
K 0.67* n.s. n.s. n.s. n.s.
Ca -0.69* -0.59* -0.70** -0.63* n.s.
Mg n.s. n.s. -0.70** -0.70** n.s.
B 0.66* n.s. n.s. n.s. 0.70**
Fe n.s. n.s. -0.61* -0.61* n.s.
Al 0.64* n.s. n.s. n.s. n.s.
Cu n.s. n.s. n.s. n.s. -0.67*
Fruit
Ca -0.60* -0.7l** -0.65* n.s. n.s.
Mg n.s. -0.72** -0.72** -O.69* n.s.
B n.s. —0.60* n.s. n.s. n.s.
Fe n.s. n.s. n.s. —0.67* n.s.
Al n.s. n.s. n.s. -0.69* n.s.
Cu n.s. n.s. n.s. n.s. —0.77**
Zn n.s. n.s. -O.63* n.s. -0.63*

 

*Significant at the 5% level.
**Significant at the 1% level.

34

TABLE 9. Highly significant multiple correlations between
water core and mineral content.

 

 

 

 

Variables R
Dependent Independentsa Value
Fruit analysis, survey, 1969
water core - K + Cu 0.55

n n (log) K — (log) Ca 4' (log) Mn 0.71

" " (log) K - Ca + (log) Mn +

(log) Cu 0.69

" " K - Ca - A1 + Mn + Cu 0.80

" " (log) Ca - (log) Zn + (log) Mn 0.63

Leaf analysis, survey, 1969

water core - N + an 0.95

 

Graham Station 1968

 

water core — fruit B - leaf Ca 0.88

 

a . . . . .
(-) or (+) indicates Sign of partial correlation.

35

TABLE 10. Highly significant multiple correlations between
breakdown (BD) and mineral content.

 

Variables

 

 

 

 

 

R
Dependent Independentsa Value
Survey, fruit, 1968

BD severity - K2 + P4 0.51

BD total - (log) Ca + Mg4 0.54

BD severity - (log) Ca - crOp 0.56

BD total - (log) Ca - K2 + Mg4 0.60

30 total - (log) Ca - K2 + P4 0.59

BD total — (log) Ca - K2 + Mg4 + (log) B 0.65

BD CA storage + Mg - Cu + diameter 0.59

Survey, fruit, 1969

ED 1 st.harvest - (log) Ca + (log) Mn 0.61

BD " " + Mn - B 0.58

BD " " - (log) K - (log) Ca + (log) Mn 0.70
'BD " " - (log) K - (log) Ca + (log) Mn +

(log) Cu 0.75

BD " " - K - Ca - B + Mn 0.69

BD " " - K - Ca - Al + Mn + Cu 0.80

BD second " - Ca + Zn 0.54

Survey, leaf, 1969

ED lst harvest - N + an 0.84

BD " " - (log) N - Mg4 + Mn2 0.89

BD " " - N - Mg3 - B + an 0.91

80 2nd " - (log) N - Mg? + an 0.58

 

*(-) or (+) indicate sign of partial correlation.

36

Fig. 6. Severity of internal breakdown as
related to the Ca level of smaller-than-
average (S, A) and larger than average
(L,IA) fruit in the 1968 survey, June
samples.

37

 

175 '—

140 .—

O5.

>.:¢m>um

0 5
7 3

23033.;

b-

 

0.5

FRUIT CALCIUM (%)

38

fruit Ca levels than fruit with lower-than-average Mg
levels (Fig. 7). Leaf Mn was most closely positively
associated with breakdown in 1969. In 1968, there were
no multiple correlations between breakdown and leaf
analysis which met the selection criteria. In 1969,

leaf N and Mg were most closely related with a negative
sign (Table 10). The results with water core were
similar except that fruit Zn and Al were negatively
associated and fruit Mn and Cu were positively associated

with water core (Table 9).

Core browning vs mineral elements.

While only negligible amounts of core browning
developed in air storage, core browning in fruit stored
in controlled atmospheres was extensive. The incidence
of core browning decreased with increasing levels of
fruit Ca, K, P, Zn and Mn (Table 8 and 12). Core
browning decreased with increasing leaf K, B, P and Ca

and increased with increasing leaf N, (Tables 7 and 8).

DISCUSSION
The large variations in the incidence of internal
breakdown of 'Jonathan' between the seasons of 1968 and
1969 were anticipated since similar results were reported

by Martin 22 El. (22).

39

Fig. 7. Percent breakdown in samples from the
1968 survey as related to the Ca level
of fruit with (A, 0) less than average
and (B, 0) more than average Mg content.

40

80,.

64

:3

230ox<u¢m

P
6
1

 

0.5

 

FRUIT CALCIUM (s)

41

TABLE 11. Highly significant multiple correlations between
breakdown and mineral elements, Graham Station

 

 

 

 

samples.
Variables R
Dependent Independentsa Value
1968 breakdown + fruit K - fruit Ca 0.73
1968 breakdown + leaf B - fruit Ca 0.86
1969 breakdown - fruit Fe - russeting 0.82
aFirst order, - or + indicate sign of partial

correlation.

TABLE 12. Highly significant multiple correlations between
core browning and mineral elements.

 

Variables

 

 

 

R
Dependent Independentsa Value

1968 survey, fruit from CA storage

core browning - K + Fe + diameter 0.72
1968 leaves from Graham Station

core browning - Ca - Fe
1968 survey, fruit from CA storage

core browning + N = Mg + Mn 0.68

aFirst order, - or + indicate sign of partial

correlation.

42

The negative correlation found between crop load
and breakdown (Table 2) was in agreement with the results
of Daley (7) and others (19, 38). Sharples (38) manipulated
cropping levels of 'Cox's Orange Pippin' by thinning and
found that senescent breakdown developed only in fruit from
thinned trees. Cell number was increased slightly, whereas
cell size was increased considerably. Also, he found that
respiration rate was higher and climacteric advanced in
thinned fruit.

The consistent relationship (Fig. 2, Table 4) between
breakdown and large sized fruit has been reported by
numerous workers (1, 20, 25). Martin (19) found that
although breakdown of 'Jonathan' fruit was associated
with large cell size, this was not due to lower protein
content since protein synthesis tended to keep pace with
cell enlargement.

The high correlation between water core and breakdown
(Fig. l) agreed with the results reported by Palmer (26)
in 1931. He concluded that breakdown seldom, if ever,
develops in 'Jonathan' which do not show water core at
the time of harvest. Bramladge and Shipway (3) sorted
intact Delicious apples spectrOphotometrically using light
transmittance measurements into 4 classes of water core
intensity. Water core disappeared in storage. Internal
breakdown developed only after disappearance of water core
and to a greater extent than in fruits that never had water

core 0

43

The negative relationship between water loss and
breakdown in fruit from the Graham Station was in agree—
ment with the results of Scott and Roberts (37). Wills
(45) further showed a relationship between water loss and
loss of volatiles. The water loss was considered by Wills
to be enhancing the production of acetate esters as well
as providing a carrier for their removal from the fruit.

In contrast to these results, breakdown incidence in fruit
from the survey orchards was higher for fruit which lost
the most weight in the room-temperature poststorage period,
furthermore it was not significantly correlated to weight
loss in storage.

Pieniazek (32) found that lenticular transpiration
accounted for only 8-25% Of total transpiration from
apples, and that the layer of waxy coating on the surface
of the skin was of greatest importance in diminishing
water losses from apple fruits. Russeting, which tends
to cause shriveling, may have reduced breakdown (Table 4)
by favoring an increase in water loss. The fact that fruit
from the Graham Station was much more russeted than fruit
from the survey in 1969, may account for the greater
percent weight loss in storage for Graham Station fruit
(av. of 4.73%) than for fruit from the survey (av. of
3.08%). The relationship between weight loss in cold stor-
age and breakdown seen in the Graham Station fruit was not
observed in the survey fruit probably because the latter

lost less weight.

44

Pieniazek (31) found that overmature apples transpire
at a higher rate. This may account for the positive
correlation between breakdown and weight loss during the
room temperature period after storage since overmature
fruit were also most subject to internal breakdown.

The negative correlations found between Ca and
internal breakdown and water core (Tables 7, 8, 9, and 10)
were consistent with many reports in the literature
(24, 27, 29, 30, 39).

Ca sprays have been reported to reduce the incidence
of internal breakdown (21, 28, 29, 34) and in other
instances, to be of no effect (23). Five or 6 sprays
were usually required in order to be effective. With
'Cox's', Schumacher and Fanhauser (35) found that KNO3
sprays of -0.7%, CaNO3-0.6%, or CaC12-0.7% reduced or
eliminated flesh browning. Leaf injury was severe and
occurred with all materials. Schumacher SE 31. (36)
found that Ca sprays increased Ca in the central cortical
zone relatively more than in the outer zones.

Perring (3) described internal watery patches in
'Cox's'. The Ca concentration in every apple affected
by the disorder was low. With other elements there was
no consistent trend. At these low levels of Ca, high
concentrations of other elements appeared to be a
contributing factor in rendering apples liable to

disorders. Perring (27, 29) concluded that, with

45

'Cox's' fruit, Ca less than 3 mg/lOO gm fresh weight
lead to senescent breakdown. Less than 8 mg P/lOO g had
the same result even if the Ca level was high. Sharples
(39) reported that breakdown was more severe in fruit with
lower contents of Mg, P and Ca. Mason (24) grew Spartan
apples in pots with silica sand and varied the Ca supply
from l/8 to full. Percent breakdown decreased markedly
with increased Ca supply.

Kohl (14) found that Ca was high in the skin and
core of apples, including 'Jonathan', but that it was
much lower in cortical tissue. The tissue nearest the
calyx end, which was usually the first area to show
breakdown, had the lowest Ca content.

The negative relationship between fruit size and
Ca content found in the 1968 survey (Table 5) agreed
with the results of Martin 25 31. (22). Although the
negative correlations (Tables 7, 9 and 10) between Ca
in fruit and internal breakdown may in part reflect the
negative relationship between breakdown and fruit size,
a trend toward lower Ca content in fruit with breakdown
was seen when size was held constant (Table 6).

Blossom-end-rot of tomato and internal breakdown Of
'Jonathan' apples appear to be related to similar
environmental conditions. Both may be induced by Ca
deficiency in the fruit (8, 24). The incidence of both

disorders has been reported to increase with increasing

46

leaf N levels (41, 42) and with larger leaf—to-fruit
ratios (10, 38). In both disorders, water-soaked,
translucent areas may appear in the fruit flesh before
symptoms of the disorder become visible (7, 11). Extreme
fluctuations in moisture supply may induce blossom-end-rot
of tomato (9). By anology with blossom-end-rot of tomato,
a hypothesis that fluctuations in moisture supply increase
the incidence of internal breakdown in apple appears
reasonable. However, no experimental evidence was found
in the literature to support or refute this hypothesis.
Goor (11) found that the uptake of water by immersed
tomato fruit tissue appeared to be greater for those of
high Ca content than those low in Ca. A relationship between
Ca content and water relations of a tissue would be expected
since Ca has been associated with the functioning of
membranes (41). Treatment with ether, according to
Bukovac pp E£° (4), causes 45Ca applied to leaf surfaces
of Phaseolus vulgaris to become mobile; without ether
treatment the Ca is immobile. Goor (11) found that ether
treatment increased the incidence of blossom-end-rot of
tomato. He, also, found that leakage of electrolytes,
especially K, from chunks of tissue decreased with
increasing Ca content. Leakage of electrolytes after
removal of Ca ions with EDTA was shown by Steveninck (40)
for disks of B332 vulgaris root tissue. The hypothesis

that increased Ca would reduce internal breakdown of

47

'Jonathan' apples by maintaining a condition of normal
permeability of cell membranes to water and electrolytes,
appears to be reasonable according to the evidence cited
above.

The cells become unusually turgid and sap fills the
intercellular spaces in the water core disorder (15).
This symptom suggests that the cell membranes are functioning
abnormally with respect to permeability to water and
solutes. The negative correlation between water core
and Ca levels in fruit (Table 8) was consistent with the
hypothesis that low Ca may be responsible for the loss Of
normal membrane functioning.

Ca deficiency has been associated with membrane
damage in the apical cells of Ca-starved barley shoots
by Marinos (18). The first indisputable signs of structural
abnormalities appeared when the nuclear envelope and plasma
and vacuolar membranes disintegrated and structureless
areas appeared in the cells. This was followed by
disorganization of other structures including mitochondria
and golgi apparatus, while plastids were more persistent,
although they eventually disintegrated. Marinos concluded
that the effects of Ca deficiency on cell walls were
probably secondary.

The positive correlations between leaf B and break-
down and water core in the fruit from the Graham Station

(Table 11) agreed with the results of Haller and Batjer (12).

48

They found that soil-applied B increased the incidence

of 'Jonathan' breakdown in 3 consecutive years. In their
1941 trials, 4 pickings of 'Jonathan' were made and no
appreciable breakdown in the untreated fruit occurred,
whereas breakdown was severe in treated fruit and occurred
even in fruit of the first picking that was immature from
the standpoint Of flavor and color. The breakdown they
report may have been other than internal breakdown since
it was described as springy and firm rather than mealy and
soft. Yet Wilcox and Woodbridge (44) reported typical water
core and flesh breakdown symptoms were increased by excess
B, and Bramladge e£_§l. (2) also found that B sprays
induced water core which eventually led to breakdown and
tissue softening.

B may be associated with the mobility Of Ca. For
example, corn plants supplied with ample B and Ca had
high soluble Ca levels which were about 30% of total Ca
(Marsh and Shive, 17). The addition of B to their
treatment of no Ca tripled the amount of soluble Ca in
the tissues. The highest B treatment resulted in more
than one-half Of the Ca being soluble.

Reeve and Shive (33) studied K-B and Ca-B
interactions in tomatos grown in sand culture and found
that for any given B concentration in the substrate, there
was a progressive increase in the B content of the plants

as the K concentration in the substrate was increased.

49

B toxicity decreased with increasing concentrations of

Ca so that toxicity became negligible at the highest Ca
level. Jones and Scarseth (13) have suggested that an
upset of the Ca-B balance by a small intake of Ca, such
as may occur on acid soils, will result in the plant
having a very low tolerance for B. This suggestion that
soil pH may have a role in the development of breakdown
may be substantiated by the correlation Of high Mn levels
with breakdown in 1969 (Fig. 4). The association of high
Mn content in tobacco, soybeans and cotton with low soil
pH was reported by Tisdale and Nelson (43). High Mn,
rather than directly increasing fruit breakdown, may simply
reflect a soil condition that may be deleterious to fruit
quality for other reasons.

The positive association found between fruit N and
breakdown (Table 7) was in agreement with the results of
Letham (16) who reported that fruit from 'Sturmer pippin'
and 'Cox's' apple trees which received only N had the
largest cells and the highest incidence of internal break-
down in storage. Tiller 35 El. (42) conducted an NPK
fertilizer experiment in apples for 27 years. Increased
internal breakdown occurred with N alone on 'Cox's',
'Jonathan' and 'Sturmer'. The harmful effects of N were
largely offset by addition of PK, but apples from NPK trees

did not store as well as fruit from unfertilized trees.

50

The negative correlation between breakdown, water
core and K levels (Tables 7, 9 and 10; Fig. 5) were in
agreement with the finding of Buneman g; 31. (5) in an
earlier survey of 'Jonathan' orchards in Michigan. Taken
together, the results of the 2 surveys suggest that the
hypothesis that low K levels result in increased internal
breakdown is sound and should be tested experimentally in
Michigan. The negative relationship observed between K and
breakdown was in agreement with Tiller pp 21. (42). Overly
and Overholser (25) also reported that K used either alone
or in combination with N and P reduced the percentage of
breakdown in 'Jonathan'. Treatment with K, according to
Perring (28) decreased the incidence of senescent breakdown
in one experiment but not in another. The physiological
role of K which may be related to internal breakdown is

unknown.

CONCLUSIONS
The incidence of internal breakdown during the storage
of 'Jonathan' apples is likely to be extensive if one or
more of the following conditions exists:
(1) Large-sized fruit are grown on trees with a
light crop.
(2) Harvest is delayed past the Optimum stage of
maturity for long-term storage.
(3) Leaf or fruit K levels are relatively low (or
specifically below 1.0% in leaves in July or

below 0.6% in fruit in September).

51

(4) Levels of Ca in fruit are relatively low
(or specifically below 0.03% in September).
(5) Leaf Mn levels are unusually high (or
specifically over 400 ppm in September).
(6) A high incidence of water core occurring in
the fruit at the time of harvest.
Three hypotheses for remedial treatments to reduce
the incidence of breakdown are suggested by the correlations
which were found: (1) application of K would reduce the
incidence of breakdown in an orchard with low levels of K
in leaves; (2) applications of Ca would reduce the incidence
of breakdown in an orchard with low levels of Ca in fruit;
(3) correction of the conditions which resulted in unusually
high leaf Mn levels in an orchard would reduce the incidence
of breakdown among fruit from that orchard.
Since trees which produced fruit with a high incidence
of internal breakdown in 1969 were not the same ones with
the most breakdown in 1968, no orchard with a history of

internal breakdown was located for future experimentation.

LITERATURE CITED

Bernstein, Paul,and Roy B. Marshall. 1942. A study
of internal breakdown on 'Northern Spy' apples
in storage. Mich. Agr. Expt. Sta.figuar. Bul.
25:156-162.

 

Bramlage, W. J.,and A. H. Thompson. 1961. Effects of
early seasons sprays of boron on fruit set, color,
finish and storage life of apples. Proc. Amer.
Soc. Hort. Sci. 80:64-71.

 

 

Bramlage, W. J.,and M. R. Shipway. 1966. Loss of
water core and development of internal breakdown
during storage of 'Delicious' apples as determined
by repeated light transmittance measurements of
intact apples. Proc. Amer. Soc. Hort. Sci.
90:475-483.

Bukovac, M. J., S. H. Wittwer,and H. B. Tukey. 1956.
Anesthetization by di-ethyl ether and transport
of foliar applied radiocalcium. Plant Physiol.
31:254-255.

 

Bfinemann, Gerhard, D. H. Dewey,and A. L. Kenworthy.
1959. The storage quality of 'Jonathan' apples in
relation to the nutrient levels of the leaves and
fruits. Quart. Bul. Mich. Agr. Expt. Sta., Mich.
State Univ. 41:820-833.

Clijsters, H. 1966. Fine biochemische Erklérung
der Fleischbréune beim 'Jonathan'-apfel.
Der Erwerbsobstbau 12:234-236.

 

Daly, P. M. 1924. The relation of maturity to
'Jonathan' breakdown. Proc. Amer. Soc. Hort. Sci.
21:286-291.

 

Evans, H. J.,and R. V. Troxler. 1952. Relation of
calcium nutrition to the incidence of blossom-end
rot in tomatoes. Proc. Amer. Soc. Hort. Sci.
61:346-352.

 

52

10.

ll.

12.

13.

14.

15.

16.

17.

18.

19.

20.

53

Gerard, C. J.,and B. W. Hipp. 1968. Blossom-end
rot of 'Chico' and 'Chico Grande' tomatoes.
Proc. Amer. Soc. Hort. Sci. 93:521-531.

 

Geraldson, C. M. 1956. Control Of blossom-end-rot
of tomatoes. Proc. Amer. Soc. Hort. Sci.
69:309-317.

 

Goor, B. J. 1968. The role of calcium and cell
permeability in the disease blossom-end-rot of
tomatoes. Physiolgia Plantarum 21:1110-1121.

 

Haller, M. H.,and L. P. Batjer. 1946. Storage quality
of apples in relation to soil applications of
boron. J. Agr. Res. 73:243-253.

 

Jones, H. E.,and G. D. Scarseth. 1944. The calcium-
boron balance in plants as related to boron needs.
Soil Sci. 57:15-24.

Kohl, Wilhelm. Die Calcium Verteilung in Apfeln und
ihre Veranderung wérend des Wachstums. Doctoral
Diss. Inst. Obstbau Univ. Bonn. Germany; also in
Die Gartenbauwissenshaft 31:1966.

 

Kollas, David Anthony. 1968. Physiology of water core
develOpment in apple. Ph.D. thesis, Cornell Univ.,
USA.

Letham, D. S. 1961. Influence of fertilizer treat-
ment on apple fruit composition and physiology.
Austr. J. Agr. Res. 12:600-611.

 

Marsh, R. P.,and J. W. Shive. 1941. Boron as a
factor in the calcium metabolism of the corn plant.
Soil Sci. 51:141-151.

Marinos, N. G. 1962. Studies on submicroscopic
aspects of mineral deficiencies I Calcium deficiency
in the shoot apex of barley. Am. J. Bot.
49:834-841.

 

Martin, D., T. L. Lewis,and J. Cerny. 1954. The
physiology of growth in apple fruits. VII.
Between-tree variation of cell physiology in
relation to disorder incidence. Austr. J. Biol.
Sgi. 7:211-220.

, and . Variation between apple
fruits and its relation to keeping quality.
Aust. J. Agr. Res. 5: 392- 415.

 

 

21.

22.

23.

24.

25.

26.

27.

28.

29.

30.

31.

32.

54

, T. L. Lewis, J. Cerny, and A. Grassia. 1966.
Tree spray experiments with 'Jonathan'. Field
Sta. ReC. 6(2).

, , and . Interrelationships
of cropping level, chemical composition and dis-
order susceptibility of 'Jonathan' apples within
and between seasons. Field Sta. Rec. 6:29-36.

 

 

, and . 1967. Disorder inci-
dence and chemical composition of 'Jonathan'

apples following tree sprays of Calcium, Magnesium
and Potassium. Field Sta. Rec. 6:1.

 

 

 

Mason, J. 1970. Calcium and breakdown in 'Spartan'
apples. (Personal communications) British Columbia
Prov. Canada. Summerland Experiment Station.

Overley, F. L., and E. L. Overholser. 1931. Some
effects of fertilizer upon storage response of
'Jonathan' apples. Proc. Amer. Soc. Hort. Sci.
28:572-577.

Palmer, R. C. 1931. Recent progress in the study of
'Jonathan' breakdown in Canada. Sci. Agric. XI:
243-250.

Perring, M. A. 1968. Mineral composition of apples.
VII. The relationship between fruit composition
and some storage disorders. J. Sci. Fd. Agric.
19:186-192.

. 1968. Recent work at the Ditton laboratory
in the chemical composition and storage charac-
teristics of apples in relation to orchard factors.
Rep. E. Malling Res. Sta. for 1967, 1968: 191-198.

. 1968. Mineral composition of apples. VII.
The relationship between fruit composition and some
storage disorders. J. Sci. Pd. and Agric.
19:186-194.

. 1968. Mineral composition of apples. VII.
Further investigations into the relationship
between composition and disorders of the fruit.
J. Sci. Pd. and Agric. 19:640-645.

 

 

Pieniazek, S. A. 1943. Maturity of apple fruits in
relation to the rate of transpiration. Proc.
Amer. Soc. Hort. Sci. 42:231-237.

 

. 1944. Physical characters of the skin in
relation to apple fruit transpiration. Plant
Physiol. 19:529-536.

33.

34.

35.

36.

37.

38.

39.

40.

41.

42.

43.

44.

45.

55

Reeve, E., and J. W. Shive. 1944. Potassium-boron and
calcium-boron relationships in plant nutrition.
Soil Science 57:1-14.

 

Saito, T. 1951. On the outbreak of 'Jonathan' spot.
Studies from Inst. Hort. Kyoto Univ. 5:85-88.

 

Schumacher, Von R., and F. Fanhauser. 1966. Verhfitung
von Stippigkeit und Lagerkrankheiten. Schweizer-
ishen Zeitschrift ffir Obst und Weinbau 102:431-441.

 

 

, und K. Schaltegger. 1966. Stippenbefall
und Fruchtkalziumgehalt nach Behandlung der Apfel
und Blatter mit Kalziumchlorid. Schweiz. Z. fur
Obst und Weinbau 102:538-541.

 

 

 

Scott, K. J., and E. A. Roberts. 1968. The impor-
tance of weight loss in reducing breakdown in
'Jonathan' apples. Aust. J. Expt. Agr. and An.
Husb. 8:377-379.

Sharples, R. O. 1964. The effects of fruit thinning
on the development of 'Cox's Orange Pippin' apples
in relation to the incidence of storage disorders.
J. Hort. Sci. 39:224-33.

 

. 1967. The structure and composition of

apples in relation to storage quality. Rep. E.

Malling Res. Sta. for 1967: 185-189.

 

Steveninck, R. F. M. 1965. The significance of
calcium on the apparent permeability of cell mem-
branes and the effects of substitution with other
divalent ions. Physiol. Plantarum 18:54-69.

 

Taylor, G. A., and C. B. Smith. 1957. The use of
plant analysis in the study of blossom-end rot
of tomato. Proc. Amer. Soc. Hort. Sci. 70:341-349.

 

Tiller, L. W., H. S. Roberts, and E. G. Bollard. 1959.
The Appleby experiments. N. Z. Dept. Sci. and
Ind. Res. Bul.: 129.

 

 

Tisdale, S. L., and W. L. Nelson. 1966. Soil
fertility and fertilizers. The Macmillan Co.,
N.Y. p. 162.

Wilcox, J. C., and C. G. Woodbridge. 1942. Some
effects of excess boron on the storage quality of
apples. Sci. Agr. 23:332-341.

Wills, R. B. H. 1968. Influence of water loss on the
loss of volatiles by apples. J. Sci. Fd. Agric.
19:354-356.

CHAPTER II

INTERNAL BREAKDOWN OF 'JONATHAN' APPLE FRUIT
IN RELATION TO POSITION ON THE TREE

AND TIME OF HARVEST

Robert L. Stebbins

Michigan State University

Abstract. Fruit samples were picked from the outer,
middle and inner zones of large, mature 'Jonathan' apple
trees from the northeast and southwest sectors on three
dates. The incidence of internal breakdown Of stored
fruit increased with later maturity, and from inner to
outer zones. No significant differences were observed

due to tree sector. Fruit from the outer zone had
significantly less K, P, Ca, Mg, Cu, and B than fruit from

the innermost zone, but similar amounts of N.

Mature 'Jonathan' apple trees on seedling roots as
typically grown in Michigan have a branch-spread of 30
to 40 feet. The fruit in the interior portions are
partially shaded and never develop as much red color as

fruit well-exposed to sunlight on the exterior portions

56

57

of the tree. It is possible that development and quality
differences related to long-term keeping might distinguish
the fruit from interior and exterior portions of the tree.
Incidence of core flush and superficial scald of Sturmer
apples has been reported by Jackson (4) to be higher in
internally than on externally grown fruit, but variations
in internal breakdown were not consistent. The incidence
of internal breakdown of 'Jonathan' apples has been related
for some time to advanced maturity (2). Little was found
in the literature on the relationship of within-tree factors
to internal breakdown of the fruit after harvest.

This experiment was conducted to determine if the
tendency for some fruit to develop internal breakdown
during or after storage is related to its position on the

tree during development and growth.

MATERIALS AND METHODS

Six 40-year-old 'Jonathan' trees with a branch spread
of about 35 feet were selected for the experiment. The
trees were typical for well-maintained old 'Jonathan'
orchards in Michigan. Each tree was divided for sampling
purposes into southwest and northeast sectors and into
outer, middle and inner zones. The outer zones penetrated
no more than 2 feet inward from the outermost fruit. The
middle zone extended from the outer zone to 6-8 feet from
the vertical center-line of the main trunk. Fruits from

this zone were partially shaded. The innermost zone was

58

in the shaded area near and above the trunk. Ladders
were employed to pick the fruit sample approximately
midway between lowest and highest parts of the tree
whenever possible.

Samples were picked September 27, October 5 and
October 12, except from the sixth replication (tree)
which had been harvested by the grower prior to October
12. Samples of 25 fruit were picked at random. Ten
—extra fruit were selected for prestorage measurement of
flesh firmness, ground color, water core and mineral
analysis.

The samples were placed on molded fiber trays within
unsealed polyethylene liners in fiberboard boxes. They
were placed in air storage at 32°F immediately after
picking. Later a controlled atmosphere of 3% O2 and 5%
CO2 was established and maintained until April 10, 1969.
All samples were removed from storage April 10, 1969 and
held at 70° until May 1. Ground color was estimated by
visual comparison with Ditton Laboratory colored cards,
in which the lower numbers indicate a greenish color and
the higher numbers an increase in yellow color. Ground
color was estimated for each apple and the values averaged
for the sample.

Flesh firmness was measured on peeled cheek areas
10 fruit, 1 puncture per fruit, using a U. C. pressure

tester with a 7/16 inch tip and recorded as pounds. Water

59

core and breakdown were Observed by slicing the fruit
perpendicular to its axis at the calyx end and at the
equator. Fruit samples collected September 27 were
analyzed for P, Na, Ca, Mg, Mn, Fe, Cu, Zn, and A1 with

a photoelectric spectrometer. Samples were concentrated
eight times normal to allow more accurate determination
of the small quantities Of minerals found in mature fruit.
Nitrogen was determined by the Kjeldahl method and
potassium by flame spectrophotometry. Fruit samples for
mineral analysis included two slices taken from opposite
sides of the fruit and including skin and core but without
seeds. The slices were diced, mixed together, and a
sub-sample of about 150 grams was taken for analysis.
Samples were dried in an oven at 60° C, and ground in a

Wiley mill.

RESULTS AND DISCUSSION

There were no significant differences between fruits
taken from the southwest and northeast tree sectors for
any of the variables measured.

The incidence of internal breakdown (Table 1) appeared
to increase with later harvests. This observation was in
agreement with the findings of several workers (1, 2, 3,

4). Breakdown incidence was higher for fruit of the outer
zone and tended to decrease toward the inner zones on all
dates, however, a significant difference occurred only for

the last picking (October 12). Fruit size, as recorded by

TABLE 1. Mean percentage

60

of 'Jonathan' apples with

internal breakdown after storage according to

date of harvest

and location on the tree, 1968.

 

Harvest date

 

Zone 9/27 10/5 10/12

Outer 1.5 a 8.0 a 19.2 a
Middle 0.0 a 3.5 a 5.6 b
Inner 0.0 a 0.5 a 3.6 b

 

Note: Means followed by the same letter are not
significantly different (Pt0.05, Tukey's test).

TABLE 2. Mean weight (grams) of 'Jonathan' apples accord-
ing to date of harvest and location on the tree.

 

Harvest date

 

Zone 9/27 10/5 10/2

Outer 116.3 a 124.3 a 120.2 a
Middle 109.5 a 118.1 ab 115.7 b
Inner 106.3 a 107.8 b 108.5 a

 

Note: Means followed by the same letter are not

significantly different,

(P 0.05, Tukey's test).

61

weight in Table 2, varied inversely to breakdown between
zones, but the difference was statistically significant
only on October 5. A higher incidence of breakdown with
larger fruit has been reported by others (1, 2, 6).

Although red color was not evaluated numerically,
it was observed that fruit from the outer zones had much
more red coloration, than fruit from the inner zones.
Usually less than one-third of the surface of fruit from
the innermost zone was red while the outer fruit were more
than three-fourths red. The most consistent effect Ob-
served was the change from green to yellow color which
progressed from earlier to later harvest and outer to inner
zones (Table 3). Flesh firmness (Table 4) tended to de-
crease with later harvest. On the first and second harvest
dates, fruit from the inner zone was significantly softer
than fruit from one or both other zones.

The larger size and more advanced stage of maturity
Of fruit from the outer zones indicated by its consistently
more yellow ground color probably account for most of the
differences in incidence of breakdown. ,Differences in
mineral content may also contribute (Table 5). Perring (5)
associated low fruit Ca with increased amounts of internal
breakdown in 'Cox's Orange Pippin'. Tiller pp 31. (7)
found that applications of K along with N and P to 'Jona-
than' apple trees resulted in a lower incidence of internal

breakdown in the fruit than where N was used alone.

62

 

 

 

TABLE 3. Ground color of 'Jonathan' apples (Ditton
laboratory green-yellow color charts, 5 = green,
6 = greenish yellow) at harvest according to date
of harvest and location on the tree.
Harvest date
Zone 9/27 10/5 10/12
Outer 5.70 a 6.27 a 6.81 a
Middle 5.38 ab 6.05 ab 6.64 ab
Inner 5.14 b 5.82 b 6.08 b

 

Note: Means followed by the same letter are not

significantly different, (P’0.05, Tukey's test).

 

 

 

TABLE 4. Flesh firmness Of 'Jonathan' apples (pounds) at
harvest according to date of harvest and location
on the tree.

Harvest date

Zone 9/27 10/5 10/12

Outer 15.5 a 15.4 a 14.3 a

Middle 15.1 b 15.0 ab 14.0 a

Inner 14.7 c 14.6 b 13.9 a

 

Note: Means followed by the same letter are not

significantly different, (P 0.05, Tukey's test).

63

TABLE 5. Mineral content of 'Jonathan' apple fruits
according to location on the tree.

 

 

 

 

 

Element

Zone

N% K% P% Ca%
Outer 0.21 a 0.76 a 0.0958 a 0.0458 a
Middle 0.23 a 0.80 ab 0.0998 ab 0.0577 b
Inner 0.27 a 0.93 b 0.1133 b 0.0577 b

Mg% Cu ppm B ppm
Outer 0.0404 a 3.400 a 15.45 a
Middle 0.0445 ab 3.825 ab 17.44 ab
Inner 0.0484 b 4.343 b 19.95 b

 

Note: Means followed by the same letter are not
significantly different (P 0.05, Tukey's test).

64

The results of this study emphasize that in experiments
where fruit samples are picked for storage or mineral
analysis, sampling should be restricted to defined zones
of foliage. It appears that, within the limited scope Of
this experiment, any sector of the tree may be sampled for

these purposes.

L ITERATURE C ITED

Bernstein, Paul and Roy E. Marshall. 1942. A study
of internal breakdown on 'Northern Spy' apples
in storage.'Mich. Agr.'Expt. Sta. Quar. Bul.
25:156-162.

 

Daly, P. M. 1924. The relation Of maturity to
'Jonathan' breakdown. Proc. Amer. Soc. Hort. Sci.
21:286—291.

 

Jackson, D. I. 1967. Relationship between cell size
in the cortex and pith of apples and varietal
susceptibility to internal breakdown and core
flush. N. Z. J. Agr. Res. 10:319-322.

 

Jackson, D. I. 1967. Storage of 'Sturmer' in relation
to date of harvest. N. Z. J. Agr. Res. 10:301-311.

Perring, M. A. 1968. Mineral composition of apples.
VII. The relationship between fruit composition and
some storage disorders. J. Sci. Fd. Agric.
19:186-192.

Sharples, R. O. 1964. The effects of fruit thinning
on the development of 'Cox's Orange Pippin' apples
in relation to the incidence of storage disorders.
J. Hort. Sci. 39:224-233.

 

Tiller, L. W., H. S. Roberts and E. G. Bollard. 1959.
The Appleby experiments. N. Z. Dept. Sci. and
'Ind. Res. Bul. 129.

 

65

CHAPTER III

THE EFFECT OF Z-CHLOROETHYLPHOSPHONIC ACID (CEPA)
ON RED COLOR, MATURITY AND INTERNAL BREAKDOWN

OF 'JONARED' APPLES

Robert L. Stebbins

Michigan State University

Abstract. The application of 250 ppm 2-chloroethylphospho-
nic acid to 'Jonared' apple trees on August 27, 1969‘
hastened the develOpment of red skin color. The effect

on red color was visible within 1 week of application, but
with natural color development, treated fruits were in-
distinguishable from controls by October 3. Changes in
ground color, flesh firmness, weight loss in storage and
incidence of internal breakdown indicated that CEPA-treated
fruit were more mature. CEPA did not affect fruit size.
CEPA fruit could have been harvested commercially a week
earlier before it had grown to a size which rendered it

more susceptible to internal breakdown.

66

67

The incidence of the internal breakdown disorder of
'Jonathan' or 'Jonared' apples usually is greater in fruit
of advanced maturity. The demand for considerable red
coloration of fresh market fruit often results in the
picking of over-mature fruit for storage. Often fruit
which remain relatively small even at an advanced stage of
maturity do not develop internal breakdown while larger
fruit in the same lot may. Especially in years with light
crOps, when fruit tend to become large and thus susceptible
to breakdown, it might be advantageous to stimulate earlier
maturity. The fruit could then be harvested earlier before
it becomes unusually large. Since ethylene has long been
known to advance apple maturity (1), an experiment was
conducted to determine if 2-chloroethy1phosphonic acid
(CEPA) would advance maturity and allow earlier harvest

while the fruit was smaller.

MATERIALS AND METHODS
Eight trees of 'Jonared', an early-coloring mutant
of 'Jonathan', were selected in a commercial orchard near
Laingsburg, Michigan. The trees were 18 years old and
bearing a heavy crop. The east half of each of four trees
in a randomized-block design was sprayed with 250 ppm
CEPA on August 27. The other trees were used as untreated

controls. A commercial spreader-sticker, multifilm X77*

 

*Colloidal Products Corp.

68

at 500 ppm, was included. On September 17, 10 ppm of
the Na salt of NAA was Sprayed on the CEPA-treated parts
of trees in two replicates.

Samples of 25 fruit were picked in a random manner
from the east half of each tree on September 15. One-
bushel samples were picked on September 20, 27 and October
3. Ten-fruit subsamples within a size range of 2 1/2 to
2 3/4 inches diameter were weighed before and after storage
to determine weight loss. Flesh firmness was measured on
similar samples using a U. C. fruit pressure tester with
a 7/16 inch tip and recorded as pounds. Under-color was
estimated with the aid of Ditton Laboratory apple and pear
color charts in which greenish, 4, to yellowish, 8, shades
of color are numerically rated.

Samples were stored in air at 36-38°F, within 4
hours of harvest.. They were removed from storage on
December 9 and held in air at 70°F until December 22.

Eight co-workers served as judges to rate the coded boxes
of fruit from each harvest in order from least to most red
color. Diameter, ground color and incidence of internal
breakdown of 50-fruit subsamples were measured. The
respiration rates of lS-fruit subsamples from the September
27 harvest were measured four times daily from September 29
to October 2 as net CO2 evolution employing an infra-red

detector.

69

RESULTS AND DISCUSSION

The CEPA fruit from the first and second harvests
had more red color according to the judges ratings
(Table l). The difference between sprayed and unsprayed
half-trees was quite obvious on September 4, one week
following application of CEPA. The increase in red color
occurred even though there was no influence on fruit size
(Table l). Edgerton and Greenlaugh (2) reported a
reduction of fruit size due to CEPA sprays applied to
'Democrat' apples 10 days after full bloom. However,
although the size of CEPA-treated fruit was reduced 2 weeks
after application, they found no significant difference in
fruit size at harvest time.

CEPA-treated fruit were estimated to have sufficient
color for commercial harvest by September 27, one week
before the control fruit were judged by the grower to have
sufficient color for fresh market purposes. During the
one week period between Sept. 27 and Oct. 3 the fruit
averaged a 5 mm gain in diameter. This continued growth
resulted in larger, more mature fruit which were more
susceptible to internal breakdown.

All parameters of maturity measured, flesh firmness,
under color and anthocyanin development, indicated that
CEPA-treated fruit were more mature. Differences in
pressure and under color were rather slight in contrast

to the quite obvious difference in red over-color. These

70

TABLE 1. Effect of a 250 ppm foliar spray of CEPA on
mean values of several characteristics of
harvested 'Jonathan' apples.

 

Harvest Level of
Date Control CEPA Significance

 

Size (diameter in mm, 50 fruits)

9/20 59 59 n.s.
9/27 61 61 n.s.
10/3 66 63 n.s.

Red color (ranking)a

9/20 2.7 6.6 ---
9/27 3.4 5.6 ---
10/3 4.5 4.6 ---
Ground color (chart numbers)b
9/15 4.35 5.00 .05
9/20 7.20 7.69 n.s.
9/27 7.57 7.89 n.s.
10/3 7.93 7.91 n.s.
Flesh firmness (pounds)
9/15 20.27 19.30 .05
9/20 17.54 17.11 .05
9/27 17.25 16.73 n.s.
10/3 17.19 17.11 n.s.
Weight loss during storage (%)
9/20 3.87 4.26 .10
9/27 3.10 3.92 .05
10/3 3.86 4.62 .10

 

a1 = least, 8 = most.

bLow number = green; high = yellow.

71

findings were in agreement with the results of Allen (1),
who treated 'Gravenstein' apples with ethylene after
harvest. He observed a change in skin color from light
green to greenish yellow, softening of the flesh, and an
increase in reducing sugars and decrease in acidity.

Water core at harvest was not apparent until October
3. At this time, 80% of the subsamples from CEPA treat-
ments had water core, whereas the controls had none. Like-
wise, with the exception Of one fruit, internal breakdown
was confined to the CEPA-treated fruit picked October 3.
The extent of breakdown was small (5%), but all fruits were
rather small, being 59-66 mm in diameter, and relatively
little breakdown was expected.

ReSpiration rate ranged from 5.5 to 9.5 mg COz/Kg/hr
with no indication of a climacteric. There was no signi-
ficant difference in respiration due to treatment. This
was surprising since ethylene applications usually increase
the respiration rate and hastens the onset of the
climacteric (4). A rise in respiration rate Of CEPA—
treated fruit may have occurred earlier, before the time
of measurement. Later, the respiration rate Of the control
fruit may have risen to equal that of the treated fruit.
This possibility seems likely since other aspects of
maturity were not significantly different one week later.

Postharvest transpiration of water by apples has been

reported to decrease with advancing maturity until Optimum

72

maturity has been passed, when they again transpire at

a more rapid rate (3). CEPA fruit (Table l) appeared to
lose more weight than controls whether picked slightly
immature on September 20 or later. Water loss differences
for fruit picked September 20 and October 3 were significant
only at the 0.1 level. September 27 was considered to be
the Optimum picking date for storage; it was subsequently
found that the treated and control samples followed the
reported trend toward increased weight loss after this

date.

An average of 9 fruits drOpped from control half-trees
as compared with 27 fruits from CEPA-sprayed trees between
9/27 and 10/3. Fruit drOp was more severe in the week
following application than in later weeks. Edgerton and
Greenlaugh (2) also observed extensive thinning of apples
after application of CEPA. Stimulation of preharvest drop
could seriously limit the usefulness of this chemical,
especially since there was no apparent counter influence
of NAA. The oldest spur leaves also abscised following
treatment.

The results suggest that CEPA treatment, especially
of light-cropping trees, would allow earlier harvest of the
fruit at a smaller size. The treated fruit in this
experiment had sufficient red color to permit a one week
earlier harvest without adverse effects on storage quality

or the develOpment of internal breakdown.

LITERATURE CITED

Allen, F. W. 1930. The influence of ethylene gas
treatment upon the coloring and ripening of
apples and pears. Proc. Amer. SOC. Hort. Sci.:

 

Edgerton, L. H., and W. J. Greenhalgh. 1969. Regu-
lation of growth, flowering and fruit abscission
with 2-chloroethanephosphonic acid. J. Amer. Soc.
Hort. Sci. 42:231-237.

 

 

Pieniazek, S. A. 1943. Maturity of apple fruits in
relation to the rate of transpiration. Proc.
Amer. SOC. Hort. Sci. 42:231-237.

Spencer, M. 1965. In Bonner J. and J. E. Varner.
Plant Biochemistry. Academic Press, N.Y. p. 817.

73

CHAPTER IV

CALCIUM-RICH CRYSTALS IN APPLE TREES AND FRUIT

Robert L. Stebbins

Michigan State University

Abstract. Single crystals and clusters of crystals or
druses found by polarized light microscOpy in tissues

of Pyrus malus L. were found to contain Ca, 0, and C using
the electron microprobe. Crystals insoluble in 20% acetic
acid were found in cells adjacent to the vascular tissues
near the pedicel in mature fruit and in dormant flower
buds, stems, petioles, shoot apex, roots and callus tissue.
Deposition Of Ca as crystals may restrict translocation of
Ca into cortical cells of apple fruit which may result in
an increased incidence of internal breakdown due to low Ca

levels in those cells.

Molisch (9), in 1913, described precipitates of Ca as
carbonate, phosphate, tartrate, sulfate and, most commonly,
as oxalate. A positive relationship between oxalic acid
concentration in the stem and susceptibility to a Ca—

deficiency disorder in Nicotiana tabacum was described by

74

75

Brumagen and Hiatt (4). They suggested that high levels Of
oxalic acid in the upper stalks and young leaves of
susceptible varieties apparently induce Ca deficiency

by interfering with translocation and utilization Of
absorbed Ca.

Chang §£_al,(5) found that symptoms Of a Ca-deficiency
disorder in young tobacco leaves increased with temperature
from 21 to 30°C. The Ca content of the stems increased as
temperature increased, suggesting that Ca was immobilized
in the stems at higher temperatures. A similar phenomenon
with maize seedlings was observed by Walker (15). At
21°C soil temperature, leaves appeared normal. At each
one-degree increment higher temperature, symptoms were
more severe. The concentration of Ca in the maize shoots
did not indicate a Ca deficiency level. Ca concentration
in the top half of the blades of the youngest two leaves was
in the deficiency range. Whether the immobilization of Ca
in maize and tobacco was related to crystal formation was
not made clear by either Chang gg_al,(5) or Walker (15).

Several authors have reported that calcium oxalate was
a waste product which was neither dissolved nor re-used by
the plant (3, 9). Even with Ca starvation, calcium oxalate
crystals did not dissolve, according to Muller (10).
Wardowski (16) and Scott (13) reported a tendency for the
crystals to disappear in later stages of development of

the plant. Scott (13) described, in Ricinus communis,

 

76

crystals suspended in protOplasmic strands in vacuolating
cells. The larger druses are enclosed in a cellulose
sheath and anchored to the cell wall by one or more hollow
cellulose stalks. The mature solitary crystal was enclosed
within a heavy cellulose sheath. In the mature, leafless
lower stem, he reported, a few empty crystal sheaths were
present and indicated the disappearance Of druses, and
starch grains developed within the former crystal idioblast.
This disappearance of crystals was said to be very common
in the inflorescence and fruiting axis.

Since Ca deficiency has been related to susceptibility
to internal breakdown of the apple fruit (14), this Study
was undertaken to examine the formation of crystals as a
possible cause of Ca deficiency in the cortex of this

fruit.

METHODS AND MATERIALS

All apple tissues for cryostat sectioning were cut
with a razor blade and immediately mounted and frozen in
Optimum Cutting Temperature Compound (OCT -15 to -30°C,
Fisher Scientific Company), according to the method of
Rasmussen (11). Sections were cut with a cryostat at
-20°C. They were dried in air and examined under
polarized light. Individual crystals, or more often,
clusters of crystals, which will be referred to as

"druses," exhibited birefringence when the plane of

77

polarized light was rotated. It was more difficult to
observe birefringence in druses because only the individual
crystals of which they were composed changed from blue to
yellow.

Crystals were extracted from short shoots on year-old
seedlings by mascerating in a mortar and pestle with a few
ml of water. Druses survived this treatment with no
apparent change. Drops Of material thus prepared were
placed on slides and treated with 20% acetic or 0.1 N HCl.

The procedures employed in examination for crystals
by micrOprobe are described by Rasmussen g£_al. (11).
Sections for micrOprobe analysis were mounted on polished
carbon discs. Identification of elements present in typical
crystals was accomplished by scanning the x-ray Spectrum
emitted during bombardment of the crystal. Line profile
analysis showed the relative quantities Of various elements
in different parts of the section. Oscillograms showed

the distribution of a given element over the section.

RESULTS
Ca-rich crystals (Fig. l) were found near the stem
in a mature 'Jonathan' apple which had been in cold storage
at 38°F for 4.5 months and exhibited severe internal
breakdown. No crystals were found in the large cortical

cells or in the epidermis.

78

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Iflnumwp mounx mo .OHUCHE «Emumoaaflomo ucmuuso mHmEmm wmum>mu
.umma “SBOoxmmun Hmcuwucfl nuwz madam mudume m mo HOOHDOQ

map Home mwaocsn HMHSOmM> ou uneconom maamo Hanan cw wamumhno

.H

O mloflrm

79

x 00nd

>an

 

xoon

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80

The x-ray spectrum was scanned while the beam rested
on the crystal shown in Fig. 1, right. The crystal was
extremely high in Ca. It contained about 8 - 10% O and
about 10% C. Exact ratios could not be obtained because
the counts fluctuated, probably due to changes caused by
the heat of the electron beam. A relatively small amount
of K was found, but it is not known whether this was part
of the crystal or merely deposited on the surface. Scanning
showed none of the following elements to be present: B,

Na, Si, Mg, Zn, A1, Fe, Mn, Cu, P, S. Pb, Ni, Cr, v, Ti.
Similar crystals found by polarized light microscopy were
insoluble in 20% acetic acid.

Crystals were found in a dormant apple bud (Fig. 2).
Partial scans of these and other crystals corroborated the
results of the first complete scan. Ca was the only
metal found in large concentration.

Samples Of the bark of 'Jonathan' apple trees Of
bearing age collected in January contained many crystals.
Near the apex of the previous season's growth rectangular
and druse crystals were found. These were located in
rectangular cells between the sieve elements and the
periderm, Often in longitudinal rows (Fig. 3). The crystals
were either druses from 9 to l4u in diameter or rectangular,
about 28 x l4u. Bark from a limb about 5 years old sampled
at the same time appeared to have fewer druses but many

more rectangular crystals (Fig. 5). The rectangular

81

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amumuon 03» mo puma unfl3onm EonoHHHomo ucmnuso mamfiom mmum>mu
.uwma upon Hm3OHw mamas unmEHOC mo coHqum mmouo EH mamumhuu

.N

.36.

82

xoon

 

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xoon

>xnn

xoa—

L

. putt:
.:.l

>an

\ .6

En.»

83

.coflusnfluumwp mounx MO .uanH
«GOHuHOQ Hmucmo unmflu mo ucmEmmuchm .THUDHE “Amy puma co
Enmpflumm .Emumoaaflomo ucmnuso madame mmum>mu .umma "nuzoum
m.cOmmmm m50w>mum on» NO mpoonm madam mo xumn EH mamummuo mu

.m

emufih

84

 

500x

25kV

500x

25kV

I28X

25kV

85

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“COHDSQHHDMHU woulx mu ROHUCHE «EMHmOHHflomO ucmunco OHQEMm

OWHO>OH

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.v

.mem

86

xoon.u

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87

Fig. 5. Ca crystals in bark from an old apple limb;
left, reverse sample current oscillogram;
right, Ca x-ray distribution.

Fig. 6. Ca x-ray distribution in petiolar xylem
(left) and phloem (right).

88

 

25kV 1,000X 25kV 1,000 X

   

25kV 500x 25kV 500x

89

crystals, which measured about 22 x 6p, were arranged in
longitudinal rows within septate fibers. These were
located very close to the cambium where numerous phloem
rays were evident.

Druses (Fig. 4) were found in the region of
elongation immediately below the apical meristem of a
rapidly-growing apple seedling. Similar crystals were
found in the petioles of both young and old leaves. Many
crystals were found in petiolar phloem, but very few in
petiolar xylem (Fig. 6). Druses occurred singularly or
in rows in parenchyma cells between the sieve tubes and
epidermis. Rectangular crystals apparently deposited
in septate fibers were found in petiolar phloem. Petiolar
phloem of a senescing leaf appeared to be virtually
"choked" with rectangular crystals. Crystals also

occurred in callus tissue and in old roots.

DISCUSSION
The much higher Ca content of stems and the core
region of apple fruits in comparison with the flesh, as
observed by Wilkinson and Perring (17, 18) may be due to
the presence of crystals such as those which were observed
deposited along the vascular bundles (Fig. l). Deposition
of Ca in this region may deprive the cells of the middle

cortex of Ca.

Bark of mature Delicious apple trees, according to

Batjer pp 31, (1) may contain as much as 4.0 to 4.5% Ca on

90

a dry weight basis. Much of this is probably deposited

in septate fibers as described by Fahn (8). These fibers
are characterized by the presence of internal septa and
usually, of a living protOplast. Evert (7) described them
as fiber sclereids with associated crystal-containing cells.
Under polarized light, it was difficult to distinguish
between fiber sclereids and crystal—containing cells.
Probably deposition as crystals in the stem, under most
conditions, simply removes excess Ca from the system.
However, if environmental conditions stimulated formation
of crystals beyond the normal rates, lateral transport and

deposition could seriously inhibit acropetal transport of Ca.

Although a close correlation exists, as shown by
Chandler (6), between Ca content and total oxalates in
the leaves of many species Of trees, it is not known
whether Ca is absorbed as a result of oxalate formation
or oxalate is formed in response to absorption of Ca.
Richardson and Tolbert (12) found that the product,
oxalic acid, inhibits an enzyme, glyoxylic acid oxidase,
which is capable of catalyzing the synthesis of oxalic
acid. Precipitation by Ca would remove this product
inhibition, in which case oxalate would be formed in
response to absorption of Ca. Beevers (2), however,
found that oxalate synthesis may occur as a by—product
of acetate utilization in the TCA cycle. It is not
known which system is responsible for oxalate formation

in apple fruits.

10.

LITERATURE CITED

Batjer, L. P., B. L. Rogers,and A. H. Thompson. 1952.
Fertilizer applications as related to nitrogen,
phosphorus, potassium, calcium, and magnesium
utilization by apple trees. Proc. Amer. Soc.

Hort. Sci. 60:1-6.

 

 

Beever, H,and Cicheng Chang. 1968. Biogenesis of
oxalate in plant tissues. Plant Physiol.
43:1821-1828.

Bornkamm, R. 1965. Die Rolle des Oxalates in Stoff-
wechsel hOheren grfinen Pflanzen. Flora 156:139-171.

Brumagen, D. Mn and A. J. Hiatt. 1966. The relation-
ship of oxalic acid to the translocation and utili-
zation of calcium in Nicotiana tabacum. Plant and
Soil 24:239-249.

 

 

Chang, S. Y., R. H. Lowe,and A. J. Hiatt. 1968.
Relationship of temperature to the development
of calcium deficiency symptoms in Nicotiana
tabacum. Agron. . 60:435-436.

 

Chandler, R. F., Jr. 1937. Certain relationships
between the calcium and oxalate content Of foliage
of certain forest trees. J. Agr. Res. 55:393-396.

Evert, R. F. 1963. Ontogeny and structure of the
secondary phloem in Pyrus malus. Am. J. Bot.
50:8-37.

 

Fahn, A. 1967. Plant Anatomy. Pergammon Press.
Oxford. p. 87.

Molisch, H. 1913. Mikrochemie der Pflanze, 3. 46-53.
Jena Verlag Gustav Fischer.

 

Mfiller, W. 1923. Uber die Abhangigkeit der Kalkoxalat-
bildung in der Pflanze von den Ernahrungsbedingungen.
Beihefte Z. Botan Centralbl. 39:321-351.

91

ll.

12.

13.

14.

15.

16.

17.

18.

92

Rasmussen, H. P., V. E. Shull,and H. T. Dryer. 1968.
Determination of element localization in plant
tissue with the microprobe. Devel. in App.

Spectros. 6:29-42.

Richardson, K. E.,and N. E. Tolbert. 1961. Oxidation
of glyoxylic acid to oxalic acid by glycolic acid
oxidase. J. Biol. Chem. 236:1280-1284.

 

 

Scott, F. M. 1942. Distribution of calcium oxalate
crystals in Ricinus communis in relation to tissue
differentiation and presence of other ergastic
substances. Bot. Gaz. 103:225-246.

 

Sharples, R. C. 1967. The structure and composition
of apples in relation to storage quality. Rep. .
Malling Res. Sta. for 1967: 185-189.

Walker, J. 1969. One degree increments in soil
temperature affect maize seedling behavior. Soil
Sci. Amer. Proc. 33:729-736.

Wardowski, Wilfred F. 1966. Morphological and histo-
logical development of the Golden Delicious apple
(Malus domestica Bork.) as influenced by leaf
nitrogen. Ph.D. Thesis, Mich. State Univ. Hort.
Dept. East Lansing, Michigan.

 

Wilkinson, B. G.,and M. A. Perring. 1965. The mineral
composition of apples III. The composition of
seeds and stems. J. Sci. Food and Agric. 16:438-
441.

, and . 1964. Further investigations of
chemical concentration gradients in apples.
J. Sci. Fd. and Agric. 15:378-384.

 

CHAPTER V

THE INFLUENCE OF TRANSPIRATION AND PHLOEM TRANSPORT
ON ACCUMULATION OF 45Ca IN APPLE LEAVES AND
IN TOMATO LEAVES AND FRUIT OF PLANTS

GROWN IN SOLUTION CULTURE

Robert L. Stebbins

Michigan State University

Abstract. Experiments were conducted to determine whether

45Ca in apple seedlings (or rooted

the accumulation of
layers of apple) or tomato fruit is influenced by: (1)
transpiration rate, (2) phloem transport, (3) kinetin
applications, (4) age of leaf, and (5) length of one-year-

45 I O O 0
Ca accumulation in leaves increased with

old stem.
increasing rates of transpiration. The rate of 45Ca
accumulation in leaves was inversely related to the length
of the stem.

Accumulation of Ca in tomato fruit increased with
increasing transpiration rate of fruit relative to that

of leaves. Although young leaves accumulated 45Ca more

93

94

rapidly than old leaves, no difference in the rate of
transpiration between young and old leaves was observed.
More 45Ca accumulated in mature leaves below rapidly-
growing shoot tips than on pruned shoots. Cytokinins had

45Ca into old leaves. Girdl-

no effect on translocation of
ing experiments showed that translocation Of Ca was in the
phloem. It is proposed that Ca moves in the phloem and
leaks into the sylem at increasing greater rates as it
approaches the younger stem and growing apex.

The physiological disorders of apple fruit known
as bitter pit and internal breakdown have been associated
with low levels of Ca in the fruit (28). This fact has
generated interest in the factors which affect the Ca
levels of fruit. In the literature, the effect of trans-
piration (15) and of metabolic activity (9) on transport
of Ca have been reported.

Koontz and Foote (15) found that Ca accumulation

by leaves Of Phaseolus vulgaris was not influenced by

 

transpiration rate. They enclosed leaves in a plastic
container. Transpiration differences were established
by varying the air flow and shading the leaf. Air was

first dried by passage through a CaSO column. Transpir-

4
ation was determined by trapping water in another CaSO4

column and weighing.

95

Gerard and Hipp (10) reported that tomatos grown
under lower evaporative conditions had a higher Ca con-
tent and lower K/Ca ratios than those grown under high
evaporative conditions. They concluded that reduction
in leaf transpiration enhances Ca movement into the fruit.

Wiersum (37) found that 45

Ca entered only the extremely
young tomato fruits. Since colored dyes failed to enter
the older fruit, he concluded that only the young fruits
transpired. When fruiting clusters were enclosed in
polyethylene bags, the fruit absorbed much less Ca than
unbagged fruit. Bagged fruit showed a high incidence of
blossom-end rot, a Ca deficiency related disorder.
Wiersum also reported experiments with fruiting branches
cut from apple trees. These were held 3-4 days in a

45Ca. Some Ca did enter the fruit.

solution with
Bledsoe pp 31. (4) showed that the peanut fruit
did not completely develop unless Ca was available in the
fruiting medium. The Ca in the rooting medium was not
sufficient. Radioactive Ca entered all parts of the top
of the plant when applied to the rooting medium but only
entered the young gynophore, not the mature or partly
mature fruit. Wiersum (36) further showed that fast green

dye in the transpiration stream does not enter the gyno-

phores buried in the soil but does enter them when they

96

are exposed to air. He concluded that the xylem stream
does not enter the gynophore when buried in the soil.
Use of an artificial medium showed that Ca was the only
requirement from the fruiting medium needed for gynOphore
development.

Ca may also move out Of the fruits as shown by

Ziegler (38) for Cucurbita maxima. He injected 45Ca

 

into fruit over the vascular bundle and found radioactivity
in the stem 13 cm from the fruit 4 hours later. Movement

of 45

Ca from apple fruits into adjacent leaves was reported
by Martin (19).

Several workers (3, 20, 21) have reported that Ca
translocation takes place exclusively in the xylem. Mason
and Maskell (20) found no evidence that Ca moved either
upward or downward via the bark. They girdled cotton
plants and calculated the total amount of element above
and below the girdle 24 hours later. Accumulation below
and a decrease above the girdle would indicate upward
movement via the bark. Their results showed a slight
decrease in Ca both above and below the girdle. They
repeated the experiment using periods of 48 to 52 hours
during which they established that uptake had taken place.
Again there was no Sign of accumulation. In 1936, Mason
92 21.(21) reported more complicated girdling studies

which further suggested a lack of phloem transport of Ca.

Their experiment included two girdles with a section of

97

leafy stem between. The apical region Of such plants had
significantly less Ca than controls but the total content
appeared to have increased slightly during the experiment.
The basal region, even though ringed, had more than twice
the gain in Ca when compared with non-ringed plants. The
difference, however, was not statistically significant.

Heat—killing a centimeter section of the leaf petiole
of Phaseolus vulgaris, according to Koontz and Foote (13),
induced no change in the amount of water transpired or Ca
deposited in the leaf.

Evidence that Ca is either absent from phloem sap
or present in only trace amounts has contributed to the
conclusion that Ca is phloem immobile (38). Lack of 45Ca
in the phloem sap from Cucurbita maxima was reported by

Eschrigh pp al.(7). After roots were dipped in a 45Ca

 

solution for 18 hours, phloem sap was collected from the
apical half of the plant and xylem from the basal half.

The xylem sap from the basal half did show activity.

Young, functioning sieve cells Showed 45Ca only at sieve
plates on callose. Only non—functioning cells had 45Ca
throughout. No 45Ca was found in the cell walls of young
phloem elements. Callose formation occurred in sieve cells
after cutting the stem. This newly-formed callose absorbed
Ca rapidly.

Sap from the sieve tubes Of the willow, Salix viminalis,

 

was obtained by Peel and Weatherly (27) using the mouth

98

parts of the willow aphid. No Ca was detected by analysis
using flame emission spectrophotometry. The xylem Of a
willow segment 30 cm in length was perfused with a 100 ppm
solution of Ca in further work by Hoad and Peel (13).
Although uptake occurred, no Ca was found in the honeydew
during the course of the experiment. Movement of K from
the xylem to aphid style exudate was found.

Lauchli (17), using an electron micrOprobe, found Ca
present in the lumen of Sieve cells Of the fruit of Piggm
sativum. He concluded that Ca, since it was found in the
lumen of sieve cells which were apparently functioning,
was transported in both xylem and phloem Of the fruit
stem.

Studies Of phloem exudate and parenchyma sap from

mature trees of Fraxinus americana, F. pennsylvanica var.

 

 

lanceolate and Platanus occidentalis by Moose (25) showed

 

 

Ca in excess of 1 mg per cc. Sap was collected in August
and September from a 2-inch slit in the trunk.

Phloem exudate from the inflorescence stalk Of 12233
flaccida, according to Tammes and Van Die (34), contained
Ca at 0.014 mg per ml. Only phloem sap was included since
the xylem was under tension from the leaves below.
Presence of Ca in phloem sap or phloem cells may, however,
reflect deposition rather than transport.

In brussels sprouts, Millikan and Hanger (24) were

able to identify the xylem with methyl blue introduced

99

through a leaf midrib flap and excise it with the
unstained phloem. Appreciable concentrations of 45Ca
occurred in both the methyl blue stained xylem and the
unstained phloem. Although within the first 10-20 minutes
45Ca occurred in all vascular tissues including the
xylem, the latter lost its original content with time,
even though the dose was still being taken up by the
midrib flap and moving down the petiole. They maintained
that it was also apparent that internal moisture tension
did not affect the pathway of movement of the isotope.
They concluded that movement of 45Ca in the stem occurred
in the phloem as well as in the xylem.

A unique system which employed 2 B sensitive semi-
conductor detectors was employed by Ringoet, pp 31. (31)

to detect movement of 45

Ca applied to the surface of oat
leaves. Downward movement occurred at high concentration
(0.02 M CaClZ) and was delayed in relation to upward
movement. Upward and downward transport velocities of
respectively 30-75 and 15-30 cm per hour were recorded.
In a later paper (32) he concluded that the slow and
quantitatively limited redistribution of Ca is most
probably not due to inability to move in the phloem
elements but to the great accumulation and absorption
capacity for Ca of the various tissues. This conclusion
is reinforced by the finding of Millikan and Hanger (22)

that chelation enhanced the movement of foliar-applied 4SCa.

100

Stout and Hoagland (33) studied the upward and lateral
movement Of radioactive isotopes of K, Na and P. They
found that radioactive P passed upward through the xylem.
Lateral movement across the cambium through living cells
was SO rapid that analysis of wood and bark, separated
after the salt had moved up, showed the test material in
both tissues. Only by separating the bark from the xylem
by oiled paper were they able to demonstrate that conduction
was taking place in the xylem.

That Ca does not recirculate in plants after its
initial deposition has been cited as evidence against phloem
transport (3). Circulation patterns for Ca in the bean
plant were determined by radioautographic means from single
aliquots of tracer administered to the roots during a

45

one-hour period by Biddulph EE_EL.(3). The Ca did not

recirculate following its initial delivery via the
transpiration stream. Later Green (11) found some

45

retranslocation of Ca in bean under stress conditions.

Millikan and Hanger (23) reported redistribution Of
45Ca in Trifolium subterraneum.and.Antivihinum majus.
For both normal and low Ca plants, 2 weeks growth in
tracer-free solution resulted in a reduction of the mean
45Ca concentration in both laminae and petioles of the

old leaves, while the isotOpe appeared in new leaves

produced during this period.

101

Kohl (l6) and Wieneke and Benson 05) found that Ca
applied to leaves of apple was not translocated to the

fruit. Martin (19) reported that 45

Ca applied to the

leaves after harvest moves back into the tree and reappears
in the following season's leaves and fruit. Injected into
the branch it tended to travel to developing leaves rather
than to mature leaves. He concluded that applied Ca is
quite mobile in apple trees. Ghosheh (12) reported that
more than 30% of the Ca in woody tissues of apple moved into
new growth.

That applied Ck: tended to move into younger plant
parts has been reported by several authors (9, 4, 23, 36).
Norton (26) applied 45Ca to the root system of the
strawberry, Fragaria spp. It was absorbed and translocated
to the youngest runner plants past older runner plants
which absorbed relatively little. These results cannot
be explained by differences in transpiration rate.

Faust (9), reported that kinetin and benzyladenine
increased the movement of 45Ca into mature leaves of apple
seedlings when the isotOpe was applied to the roots. He
suggested that movement of Ca from the vascular system to
the parenchyma tissue of the leaf blade may be influenced
by the metabolic activity of the expanding leaf. Cytokinins
would then increase movement into mature leaves by increasing

their rate of metabolism. In contrast with the findings

of Faust are those of Enayat and Hofner (6) who found that

102

kinetin, applied to another part of a tobacco leaf, did

not attract 86RbCl, 42KNO3, KH232PO4, 59 3, 45

2!
65 235804, 6OCoClz, or S4MnCl2 when the radioactive

salts were applied to the surface of the leaf. In addition,

FeCl CaCl

ZnClz, Mn

 

Quinlan and Weaver (29) found with Vitis vinifera that N-6
benzyl adenine (BA) was much more effective in stimulating
movement of 14C labeled assimilates into darkened leaves
or into leaves which were not fully expanded. BA, applied
without darkening the leaves, had little effect on‘l4C
imported into older leaves.

Evidence in the literature cited above does not
clearly establish the effect Of transpiration on Ca
accumulation in apple. Furthermore, it does not establish
the occurrence or lack of phloem transport of Ca in apple.
Therefore, experiments to establish the influence of

transpiration in apple and tomato and the occurrence

or lack of phloem transport of Ca in apple were conducted.

MATERIALS AND METHODS

The experiments were conducted in a greenhouse using
plants growing in solution culture. A nutrient solution
used by Faust(9)‘was used throughout. Aeration was provided
by forced air passing through aquarium stones. The nutrient
solution was usually changed weekly. Plants were grown in
gallon jars. Three liters of nutrient solution were placed
in the jars at the start of an experiment. Deionized water

was added, as needed, for the remainder of the week.

103

Either one-year-old apple seedlings, or rooted
layers of 'Malling Merton 106' apple rootstock clone
purchased from nurseries were used. One—year-Old pear
seedlings were used in one experiment. One experiment
involved the use of tomato plants, 'Farthest North'.

Nursery trees were held in cold storage and started
in sand as needed. When well-rooted, the sand was washed
from the roots and the plants were transferred to solution
culture three or four days prior to use.

In all experiments, 45Ca as CaCl2 was applied to the
solution at 40 u Ci per 3 liters.

At the end of an experiment, the entire shoot from
each seedling was harvested. For autoradiography it was
placed in a plastic bag and held in a refrigerator up to
several hours before the leaves were separated and taped
to a blotter. Leaves were dried in a plant press for 5-7
days. Occasionally after autoradiography, the samples
were ashed and counted. In other instances the leaves
were harvested directly into paper bags and dried in a
forced air oven. They were ground in a Wiley mill or
by mortar and pestle, ashed in a muffle furnace and trans-
ferred to stainless steel planchets. The samples were
counted with a TGC-l4 Gieger tube and automatic scaler.
Counts were corrected for self-absorbance using a curve

obtained with apple leaf ash.

104

Trees were grouped in replicates by plant size.
Randomized complete block designs were used throughout.
Plots consisted of single trees or single branches.
Whenever practical, all trees in a replicate were grown
in the same solution culture jar.

Transpiration experiments. In a preliminary

 

experiment, plastic bags were placed over the tips of apple
seedlings. Wet paper towels were enclosed and the bag

was tied tightly around the stem. Slits were cut near the
top of the bags to facilitate gas exchange. Treatments
were replicated 3 times. The experiment was conducted for
1 week in September. Samples including leaves in the bag,
below the bag and lower and upper leaves on control plants
were counted.

The effect of conditions in a polyethylene bag on Ca
levels in tomato fruits and leaves was studied. The
treatments were: (1) control in open air, (2) branch
girdled by hot wax, (3) fruiting cluster in polyethylene
bag, and (4) entire plant in polyethylene bag. A wet
towel was placed in the bag and ventilation holes were out.
A single cluster with l or 2 fruit 6 mm or less in diameter
was selected on each plant. All other fruiting clusters
were removed. Fruits were nearly ripe after 20 days and
were harvested for analysis. One leaf from each of 10
shoots constituted a sample. The first fully expanded leaf

below the terminal was chosen. Leaves from plants with wax

105

girdles were not sampled. Ca content of fruit was
determined by atomic absorption spectrOphotometry. Leaf
samples were analyzed spectrophotometrically.

In an attempt to vary only the vapor pressure
deficit, another experiment using plastic bags was
conducted. Rooted layers of 'MM 106' with new shoots
14-16 inches in length were used. An air flow through
each bag of 2,000 ml per minute was maintained by means
of a system combining capillary tubes and water barostats.
Since the bags held approximately 6,000 ml, the air in the
bags was exchanged every 3 minutes. Five plants were in
bags through which humid air was passed. Dry air was
passed through 5 more. Each plant was in a separate jar.
Solution use during the course of the experiment was
measured. The tOps of the jars were covered with plastic
to reduce evaporation and no water was added during the
experiment. Air was humidified by first heating it on the
greenhouse heating pipes and then passing it through two
different water chambers. Air was dried by passing it
over silica gel and then through a small refrigeration
unit specifically designed for drying air. Temperature
and relative humidity of the air in the bags was determined
by pumping air out of the bags past dry and wet thermo-
couples using a small electric powered pump. Fine wire

thermocouples were used to measure leaf temperature.

106

One potted plant in a polyethylene bag without air
flow was maintained for comparison. Temperature and
relative humidity were measured 3 or 4 times daily.

Vapor pressure deficit calculations were based on air
temperature rather than leaf temperature. After 8 days
the leaves from each tree were harvested, weighed fresh,
dried at 60°C, weighed and counted.

Girdling experiments. In all girdling experiments,
a section of phloem 1.5 cm in length was cut from the one-
year-old stem with a sharp knife, care being taken to do
minimum damage to xylem tissues. The girdled area was
covered with black plastic tape. Plants thus girdled
usually appeared to grow normally. After 2 weeks, if the
shoot above was not harvested, the girdles were usually
callused over.

In Experiment 1, 8 apple seedlings with new growth
8-12 inches long were used. Four seedlings were girdled
on August 2. The leaves were harvested 6 days later and
dried for 6 days. X-ray film was then exposed to the
leaves for 11 days. The leaf samples were then divided into
those from lower and upper parts of the seedlings. Radio-
activity was counted with a Geiger tube for 50 minutes per
planchet on October 6.

In Experiment 2, 8 apple seedlings were girdled

45

at 9 pm. Sixteen hours later the Ca was added to the

medium. All 8 control and 8 girdled trees were harvested

107

8 days later and the upper leaves prepared for auto—
radiography. After 12 days drying in a plant press,

x-ray films were exposed to the specimens for 2 weeks.
Slices of phloem and xylem from both above and below

the girdle were included in the autoradiographs. The
leaves used for the autoradiographs were ground and 500 mg
were ashed and counted for 1 hour.

For Experiment 3, a group of one-year-old rooted
layers of the apple rootstock clone 'MM 106' were used.

When each stock had developed, a single shoot 8-10 inches
long, they were sorted by size into 5 replicate groups of
4 trees each. Each replicate was grown in a single jar.
Treatments were established as follows: (1) control,
undisturbed plants; (2) girdled; (3) girdled and a fresh
cut through the one-year rooted layer about 1/2 inch above
the lower end, usually with removal of some roots; and (4)
girdled between a lower and one or more upper shoots to
provide leaves to feed the root system.

Samples of 500 mg of leaf ash were counted for 1 hour.
Samples of phloem from treatments 1 and 2 were counted,
also.

Cytokinin experiments. The first experiment was to
determine if girdling would reduce or eliminate the accumu-
lation of 45Ca in a cytokinin-treated leaf spot. Treatments
were: (1) none, (2) cytokinin spot, (3) girdle 0.5 cm long,

(4) girdle plus cytokinin spot. Plots consisted of l shoot

108

on a plant with 2 shoots of equal length in the first 2
replicates. In the third replicate, plots consisted of
single trees. Girdling consisted of severing and care-
fully removing a section of bark about 0.5 cm. long. In
the first 2 replicates, the current season's shoots were
girdled. A synthetic cytokinin from Shell Development Co.,
6'—benzylamine-9-(tetrahydropyran 2-yl)9H - purine was
mixed at the rate of 1 mg cytokinin per gram of lanolin.
An area of about a cm2 on the upper surface of mature
leaves near the base of apple seedlings was covered. The
experiment was started May 23rd and the tissues were
harvested May 30.

Since lack of response to cytokinin in the first
experiment may have been due to lack of penetration of the
cuticle, a second experiment was undertaken in which an
attempt was made to eliminate this difficulty. Mature
leaves were taped to a board, underside up. Small plastic
rings were attached with silicon rubber glue to form a
well. A solution of kinetin (6-furfuryl amino purine),
from Cal Biochem, in aqueous solution at 2.5 x lO-4M,
was poured into the wells and allowed to dry. Water was
applied in the same manner to control plants. There were 3
replications. The results were evaluated by autoradiography.

The effect of stem length. By pruning the apple
seedlings at different heights, trees with: (1) short
[l-l l/2 inches]; (2) medium [4-5 inches]; (3) long

[7-8 inches], lengths of one-year—old wood were grown.

109

New growth was 10-12 inches long at the start of the
experiment. A knife score through the phloem was made
just below the new growth on half of the seedlings. A
split-plot design was employed with scoring as the main
plots and stem length as sub-plots. There were 8
replications, 18 trees in all, each in a separate jar
of solution. Trees were grouped in replications according
to size. The shortest trees had fewer, shorter roots than
the taller trees. One-year-old and,current xylem and phloem
of 3 tall trees were dissected, ashed and counted separately.
After 1 week, leaves were harvested and prepared for
counting.

Influence of leaf age. That older leaves absorb less

45Ca than upper leaves has been established (9). If

transpiration is important in the distribution of 45Ca

one would, therefore, expect the younger leaves to transpire
more rapidly. An experiment to determine whether young
leaves transpire more rapidly than old leaves was conducted.
Five pairs of trees of equal size were selected. Several

of the oldest, small leaves at the bottom of the 'MM 106'
rooted layers were removed. The shoot was then pruned just
above the youngest fully-expanded leaf. Pairs of trees were
adjusted to equal numbers of leaves by removal of l or 2

lower leaves as required. Solution use over the next 3 days

was measured.

110

Then one-half of the leaves were pruned off of each
plant by either (a) removing upper leaves or (b) removing
lower leaves. Water use was measured again after 3 days.
Fresh weight, dry weight and surface area of leaves was
measured. Water use per cm2 leaf area, per fresh weight
and per g dry weight was compared.

Effect of the_g£owing shoot tip. If the growing tip
of the shoot is competing with lower leaves for Ca, removing

it should increase 45

Ca uptake in the lower leaves. An
experiment to test this hypothesis was conducted using 4
pear and 2 apple trees. The stem above the highest fully—
expanded leaf was marked. Then the shoots were adjusted to
an equal number of leaves. The entire tip above the mark
was pruned off of one of the shoots selected randomly.

After 8 days, leaves below and above the mark were harvested,

dried, weighed and counted.

RESULTS

Transpiration experiments. Conditions within the
polyethylene bags strongly suppressed translocation of Ca
in apple seedlings (Table 1, Fig. l). The vapor pressure
deficit between water in the leaf and air was probably the
environmental factor most significantly altered by the
treatment. Leaf temperature was probably several degrees
higher during the day as was found in a later experiment
(Fig. 2). Even though slits had been cut in the bags, CO2

content of the air may have been reduced also.

111

Fig. 1. An autoradiograph4§howing restricted

translocation of Ca by conditions

within a polyethylene bag compared with
lower leaves outside the bag.

113

Fig. 2. Leaf temperatures of trees in humid vs.
dry air compared with air temperature;
(a) air temperature in bag, (b) leaves
in humid air, (c) leaves in dry air.

 

 

 

115

TABLE 1. Effect of conditions within polyethylene bags
on translocation of 45Ca to leaves of apple
seedlings (counts per minute per 100 mg dry
weight of leaf).

 

 

 

 

Bagged Trees Non-bagged controls
_ Within bag; Belowbagb Upper leavesa
1.5 26.5 104.3

 

aMean of 3 trees

b2 trees

A similar experiment with tomatos (Tables 2 and 3)
showed that Ca accumulation by fruits was reduced by
placing the fruiting cluster in a polyethylene bag. When
the entire plant was in a polyethylene bag (Table 2),
fruit Ca was not reduced in comparison with fruit from
non-bagged control trees. Leaf Ca, on the other hand,
was reduced by conditions in a polyethylene bag (Table 3).
The leaves also contained less Mg, Fe, Zn, and Al.

TABLE 2. Effect of girdling and conditions in a polyethyl—

ene bag on Ca content (percent dry weight) of
tomato fruits.

 

 

Treatment Ca content
Entire plant in a plastic bag 0.2856 a
Untreated control 0.2102 ab
Fruiting cluster in a plastic bag 0.1192 bc
Wax girdle of branch 0.0704 c

 

Means followed by the same letter are not
significantly different (P 0.05, Tukey's test).

116

These results suggest that a reduced transpiration
rate of the fruit relative to that of leaves was a factor
which, at least in part, reduced the Ca content of fruit.

The results of an experiment in which apple trees
were grown in moving humid or dry air clearly indicated
that accumulation of Ca in leaves increased with increasing
transpiration rate of leaves (Fig. 3). Leaves in dry air
transpired significantly more water than leaves in humid
air (Table 4).

TABLE 3. Effect of conditions in a polyethylene bag on
mineral element content of tomato leaves.

 

 

 

Element
Treatment
Ca(%) Mg(%) Fe(PPm) Zn(ppm) Al(ppm)
Control 4.11 a 1.19 a 205 a 47.5 a 325 a
Fruit in poly
bag 3.21 ab 0.93 ab 136 ab 32.0 ab 221 ab

Entire plant
in poly bag 2.71 b 0.70 b 127 b 29.9 b 193 b

 

Means followed by the same letter are not signifi-
cantly different (P 0.05, Tukey's test).

TABLE 4. Effect of vapor pressure deficit (VPD) on
transpiration of apple trees in solution culture.

 

 

Large VPD Small VPD
Water loss (ml per
g fresh weight of
leaves 170.6 101.2*

 

Means significantly different (P 0.05, Tukey's test).

117

Fig. 3. Regression between 45Ca accumulated in
leaves and water loss by apple trees.
[*Significant at 5% level.]

u u 5

”CA Acnvnv (1,000 cpm)

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118

 

 

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119

That the contrast in humidity was probably not as great
as in the bagging experiments without air flow was
illustrated by the much higher vapor pressure differences
in a tree bagged without air flow (Fig. 4) and the
greenhouse air. The calculated difference in vapor
pressure deficit between humid and dry air (Fig. 5) was
statistically significant at each measurement period.

The largest contrast occurred at midday. Even though the
air flow was high, 2,000 ml per minute, and the air was
thoroughly dried prior to entering the bag, transpiration
by the plants was so rapid that the high VPD in the
greenhouse could not be matched in the bags supplied with
dry air. Vapor pressure deficits in the bags with humid
air flow were usually as low as in the bag with no air
flow.

Girdling experiments. In Experiment 1, 3 of the 4

 

apple seedlings with girdles on the old stem produced no
autoradiograph image. A fourth showed faint traces of
45Ca in the midribs of leaves. Counts of the leaf ash
(Table 5) confirmed the results seen in the autoradiographs.
One of the girdled seedlings wilted during the course
of the experiment indicating that the xylem had been damaged.
Such damage undoubtedly would have caused wilting since
daytime greenhouse temperatures often exceeded 80°F and

reached a maximum of 94°F. Since the intensity of radio—

activity in control leaves was rather low, another

120

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124

experiment, which included twice as many trees, was con-

ducted. The results (Table 5) were substantially the same.

TABLE 5. Effect of stem girdling on assimilation of 45Ca

by apple seedlings in solution culture (counts
per minute per 100 mg dry weight of leaf).

 

 

Experiment 1 Leaves Experiment 2
treatment upper lower leaves
Control 40* 30* 101*
Girdled l l 3

 

*Means significantly different (P 0.05, Tukey's test).

The autoradiographs from Experiment 2 (Fig. 6) show
that the phloem below, and to a much more limited extent,
above the girdle had absorbed 4SCa. The xylem appeared
to have little or no labeled Ca except along the outer
edges. The roots of 3 of the girdled trees appeared
damaged or dead at the conclusion of the experiment so
these data were discarded. Roots on the other trees
appeared to be healthy. .

These experiments offer evidence that, in the old
stem at least, transport of 45Ca may be limited to tissues
outside of the xylem, probably the phloem.

The questions of root starvation and damage to the
xylem were answered in Experiment 3. In order to

demonstrate that Ca would pass a girdle if it had access

to the xylem, a fresh cut was made across the base of a

125

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126

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127

rooted layer under water. The layer was then quickly
transferred to the nutrient solution. Strong
radioactivity in the leaves would indicate that the
girdle did not directly impede translocation of Ca in the
xylem. The question of root starvation was answered by
girdling between a lower and an upper shoot. The leaves
on the lower shoot provided photosynthates for the roots
(Fig. 7).

The question of damage to the xylem was answered
through a fortuitous accident in Experment 3. On the
fourth day, the temperature in the greenhouse suddenly
increased to 95°F and possibly higher where it remained
for several hours until the vents were Opened. In
replicates l and 3, all girdled trees wilted, indicating
that the xylem had been damaged. The girdled and root-
pruned trees in 4 of the 5 replications also wilted. Some
other non-girdled trees which were not part of the
experiment also wilted, thereby indicating the severity
of the conditions. Since 3 of the 5 girdled trees showed
no sign of wilting it would seem evident that the xylem
was not seriously damaged. The data of this experiment
(Table 6) show that 45Ca was translocated in the xylem
past the girdle in large amounts When access was provided
through a fresh cut and that the reduced accumulation of
45

Ca in leaves above a girdle was not due to root

starvation.

Fig.

7.

128

Illustration of the treatment of rooted
apple layers in an experiment to determine
(1) if Ca would pass a girdle if it had
access to the xylem and (2) if lack of
translocation past a girdle was due to
root starvation.

129

 

 

 

 

 

 

71
'

 

 

 

 

 

 

 

 

 

 

 

 

l

control girdled girdled girdled with
and cut shoot below

130

TABLE 6. Effect of girdling, leaves below the girdle
and cutting the rootegslayer, on absorption
and translocation of Ca by apple plants in
solution culture.

 

 

Treatment Counts in leaves
(total/minute)
Untreated control 1,049 a
1.5 cm girdle on past season's wood 47 b
Girdled, cut end in nutrient solution 4,392 a

Girdled between main shoot and a short
lower shoot with a few leaves 36 b

 

Means followed by the same letter are not
significantly different (P 0.05 Tukey's test).

That translocation of 45Ca via the xylem (when
access is provided through a fresh cut at the base of
the rooted layer) was much more rapid than through the
intact root system was shown in another experiment (Fig. 8).
Discs were cut from lower leaves of 3 control plants without
cuts and 3 plants with cuts at 24-hour intervals for 1 week
and autoradiographed. The plants used were similar to
those used in the third girdling experiment. Even after
7 days, the lower leaves of control trees did not accumulate
as much 45Ca as trees with a fresh cut.

Counts of phloem samples (Table 7) show that Ca did
not accumulate in large amounts in phloem below the girdle.

That Ca did move in the xylem at a reduced rate was

indicated by the low counts in the phloem of the old stem

Fig.

131

Accumulation of 45Ca in lower leaves of

rooted apple layers: (a) intact control
plants and (b) with a fresh cut at the
base of the layer allowing access of the
nutrient solution to the xylem. Leaf
discs were punched at 24 hour intervals,
ph = phloem sample.

132

 

133

above the girdle. These data suggest that girdling also

reduced root absorption of 45Ca.

TABLE 7. Effect of girdling on accumulation of 45Ca in
phloem of apple (counts per minute per 100 mg

 

 

dry bark).
Treatment Counts in phloem
Non-girdled controls 316
Below girdle 60
Old stem above girdle 29

 

Results of an experiment in which cellulase acetate
film was slipped between phloem and xylem strips on either
side of the one-year-old stem of 4 'MM106' rooted layers
also indicated the occurrence of phloem transport of 45Ca.
Since the treatment could not be performed without damage
to the phloem, 11 days were allowed for callus formation
before the plants were transferred to the medium with
45Ca for one week. In each of the 4 plants involved, one
of the 2 phloem strips produced a strong autoradiograph
(Fig. 9). However, the treatment induced callus formation
which in itself might attract Ca.

That 45Ca in the vascular system of the one-year-old
stem of apple seedlings remained in a form which allowed
subsequent movement into new growth after the seedling

was transferred to non-radioactive medium and the main

shoot was removed was shown by autoradiography (Fig. 10).

134

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10.

136

Movement of 45Ca from vascular tissues of

the old stem of an apple seedling into
regrowth after removal of the current

season's shoot and transferral to non—
radioactive medium.

 

138

The seedlings were grown in medium with 45Ca for one

week. The current-season shoot was completely removed
and the one-year-old stem and root system were washed
with non-radioactive medium before completing the transfer
to non—radioactive medium.

In order to investigate retranslocation of foliar-

applied 45

Ca, leaves were treated with approximately 2 u
Ci of 45Cac12 on November 8. Subsequent leaf fall in the
greenhouse continued for a period of almost 2 months.
Autoradiographs of strips of bark collected after leaf

fall (Fig. 11) show that some of the 45

Ca applied to
leaf laminae moved out of the leaves during senescence.
The phloem was not strongly radioactive, however. New
growth in spring was not radioactive as determined by

autoradiography.

Effect of stem length. An inverse relationship of

 

the rate of accumulation of 45Ca in leaves to the length
of one-year-old stem is illustrated by the experiment
which involved plants with short, medium and long lengths

of old stem (Table 8).

139

Fig. 11. Autoradiograph of strips of phloem from

an apple seedling showing the presence
of 45Ca which was translocated from the
leaf lamina during leaf senescence.

141

 

 

 

TABLE 8. The effect of the length of one—year-old stem
on the rate of translocation of 45Ca to leaves
of apple seedlings (counts per minute per 100 mg
dry weight of leaf after 8 days).
Length of old stem above Counts per minute
highest root, inches Non-scored Scored
1.0 - 1.5 39 a 49 a
4 - 5 14 b 8 a
7 - 8 11 b 16 a

 

Means followed by the same letter are not
significantly different (P 0.05 Tukey's test).

A comparison of the amount of 45Ca accumulated in

phloem and xylem in the plants with 7-8 inches of old

stem shows
45

that the phloem accumulated 5 times as much

Ca as the xylem (Table 9).

 

 

TABLE 9. Accumulation of 45Ca by phloem and xylem of
apple seedlings in solution culture (counts
per minute per 100 mg dry tissue).

Tissue One-year-old stem Current season stem

Xylem 887 542

Phloem 4611 2761

 

142

The transpiration rates of apple plants with only
young or old leaves were not significantly different
(Table 10). The total amount of water transpired was
related to leaf surface area (Fig. 12) in the expected

manner .

TABLE 10. Transpiration rate by upper vs. lower leaves

 

 

of apple.
Water use measurement Plants With only:
Upper leaves Lower leaves
ml per cm2 leaf area 2.275 2.808
% of rate before leaf removal 140 167
ml per g fresh weight of leaf 136.6 164.3
ml per g dry weight of leaf 466.5 579.4

 

*
The differences are not significantly different.

The young leaves were typical of those which have

45 . . .
Ca in preVious experiments.

absorbed large quantities of
That old leaves accumulate much less Ca than young leaves
has been shown both by autoradiography (Fig. 13) and counts
(Table 5).

Effect of the young growing shoot tip. Leaves below

 

a rapidly-growing shoot tip accumulated significantly more
4SCa than the same number of leaves on an adjacent shoot
of the same plant from which the tip\had been removed

(Table 11). Therefore, it was concluded that the younger

leaves do not compete with the older leaves below for the

143

Fig. 12. Correlation between leaf surface area
per 'MM 106' apple layer and water used
over a 3 day period. [*Significant at
the 5% level.]

LOSS (liters)

WATER

 

144

 

 

0,6 —
0.5 .—
O.4 '-
t
J‘ Y3310.9*O.6099X r30.64
O L.‘ \— L l 4 l
\
O 250 300 350 400

LEAF suarAcs ( 6012)

145

.mm>moa 6H0

.usmfin “mo>moa mono» .umoq .mcwapomm mamas mamcwm

0 :0 0mm mcflmum> mo mo>mma an no

mv

MO COAMMHDEZUO‘

.ma

.mE

 

147

available supply of Ca. Leaves below a growing tip
probably receive more 45Ca simply because of the greater

supply moving up in the phloem.

TABLE 11. The effect of he presence of a rapidly-growing
shoot tip on Ca absorption of fully—expanded
leaves below (counts per minute per total dry
weight of leaves). The results are for
non-pruned and pruned shoots on the same plant.

 

 

 

Treatment
Tip removed Tip remaining Shoot tipl
26,641 51,711 63,979
a b

 

Means followed by the same letter are not
significantly different (P 0.05, Tukey's test).

lCounts from shoot tips were not included in the
statistical analysis.

No tendency for 45Ca accumulation in kinetin-treated

spots on old leaves of apple seedlings was shown by

autoradiography.

DISCUSSION
More 45Ca accumulated in leaves of apple and tomato
and tomato fruit at higher rates of transpiration than at
lower rates (Tables, 1, 2, 3 and 4 and Figures 1 and 3).
This is in agreement with the findings of Wiersum (36, 37)
for tomato and peanut fruit, but is contrary to the results

of Koontz and Foote (15) for leaves of Phaseolus vulgaris.

The possibility exists that the latter workers did not

148

actually establish differential rates of transpiration,
since different rates of air flow and shading were used to
obtain the different rates. One must assume, although they
gave no data on humidity, that the air had been (completely)
dried by passage through a CaSO4 column prior to entering
the leaf chamber, otherwise regardless of the transpiration
rate, water trapped from air leaving the leaf chamber would
be proportional to flow rate.

Since the rate of 45Ca accumulation in leaves of
apple seedlings was greater in plants with short (1.0-1.5
inch), old stems, as opposed to long (4-5 or 7-8 inch) old
stems (Table 8), it is believed that the rate of trans-
location as well as root absorption affected the amount

45 45

of Ca accumulated in leaves. If Ca moved freely in

the transpiration stream, one would not expect to find

4SCa accumulation between

much difference in rate of
seedlings with 1.0-1.5 inches of old stem as compared with
seedlings with 4—5 inches of old stem. However, if Ca
moves upward through the xylem only by exchange, as
proposed by Bell and Biddulph (2) and supported by Jacoby
(l4) and Faust (9), stem length would be an important
limiting factor. If Ca moves primarily through the
phloem, the length of stem would be a limiting factor

since the cells adjacent to the phloem accumulate Ca

crystals (8).

149

Since girdling the one-year-old stem of apple

seedlings and layers severely restricted accumulation of

45Ca in leaves (Tables 5 and 6 and Fig. 6), it is

concluded that 45

Ca is translocated primarily in the
phloem of the one-year-old apple stems. These results
do not agree with those of Mason and Maskell (21, 21)

with cotton and Koontz and Foote with Phaseolus vulgaris

 

(15). A girdling experiment can indicate acropetal
transport of Ca in phloem only if the girdle severely
restricts accumulation of Ca above the girdle. Phloem
might be a normal pathway of translocation of Ca in some
plants in which girdling does not severely restrict
translocation of Ca. Girdling such plants would not stop
translocation but only force lateral tranSport into the
xylem stream. One would expect that transport of Ca in
both phloem and xylem would normally occur in such plants.
Since the experiment with apple layers with a fresh
cut in the nutrient solution (Fig. 8) showed that 45Ca
transport in the xylem is rapid, it is concluded that
lateral transport from phloem into xylem of one-year-old

stems was limited. Otherwise 45

Ca would have by-passed
the phloem girdle and entered the xylem in much greater
quantities.

45Ca by roots with

Increasing absorption of
increasing water use by leaves probably accounts for some

. 45 . . .
of the increased Ca accumulation in leaves shown in

150

Fig. 3. Since leaves below a polyethylene bag accumulated
more 45Ca than leaves in the bag (Table 1, Fig. 1), it is
concluded that restricting transpiration rates restricts
the rate of translocation as well as absorption.

The fact that the rate of accumulation of 45Ca in-
creases with increasing transpiration rate appears to
contradict the phloem transport hypothesis. Transpiration
rate is generally thought not to influence the rate of
acropetal translocation in the phloem. Increasing rates
of transpiration may increase the rate of translocation of
45Ca by increasing the rate of movement from phloem to
xylem, particularly in the current-season's growth. The
failure of the 0.5 cm girdle on current season shoots in
the first kinetin experiment to severely restrict 45Ca
accumulation in leaves above suggests that 4SCa moves more
readily from phloem to xylem in the current season's growth.
When the phloem is fully turgid and the transpiration rate
is relatively low, as under conditions of low VPD, very
little lateral transport may take place. As the transpir-
ation rate increases, the relative concentration of Ca in
phloem may increase and consequently Ca may move into the
transpiration stream more rapidly. Lateral transport
through living ray cells and possibly through the cambium,
with subsequent leakage into tracheids would logically be
expected to be a function of concentration. This process
might be more rapid toward the shoot tip. The restricted

45

movement of Ca into old leaves is consistent with this

151

hypothesis. Once in the xylem, the movement of Ca into
old leaves is unrestricted (Fig. 8).

The results of the girdling experiment are in
agreement with the findings of Martin (19) who reported
that 45Ca appeared to move exclusively in the phloem of
apple trees.

Most of the Ca in an apple is absorbed early in
the season, according to Kohl (16). This may be due to
lateral transport from the phloem into the young xylem of
the cluster base and stem. Later, as the xylem matures,
lateral transport may be restricted. The phloem, as de-
scribed by Evert (8), is also more active early in the
season than later. Translocation may be hindered by
deposition of crystals in the phloem as suggested by
Lauchlii (17).

Although the evidence clearly indicates that
translocation of 45Ca in apple stems increases with in-
creasing transpiration rate, whether this is primarily due
to an increased rate of movement in the xylem or to an in-
creased rate of transfer from phloem to xylem remains to
be resolved. The evidence clearly indicates that in the
one-year-old apple stem, 45Ca moves primarily in the

phloem rather than in the xylem.

10.

LITERATURE CITED

Barber, D. A., and H. V. Koontz. 1963. Uptake of
dinitrophenol and its effect on transpiration and
calcium accumulation in barley seedlings. Plant
Physiol. 38:60-65.

Bell, C. W., and O. Biddulph. 1963. Translocation of
calcium. Exchange versus mass flow. Plant Physiol.
38:610-614.

 

Biddulph, 0., Susan Biddulph, R. Cory:and H. Koontz.
1958. Circulation patterns for phosphorus, sulfur
and calcium in the bean plant. Plant Physiol.
33:293-300.

 

BlEdSOE, Re We, Co Le COmarrand He Ce Harris. 19490
Adsorption of radioactive calcium by the peanut
fruit. Science 109:329-330.

Bowling, D. J. E., A. E. S. Macklon,and R. M. Spans-
wick. 1966. Active and passive transport of the
major nutrient ions across the root of Ricinus
communis. J. Expt. Bot. 17:410-16.

Enayat, A., and W. Hofner. 1965. Kinetin Einfluss
auf die Verteilung Anorganischer Stoffe in
isolierten Blattern von Nicotiana tabacum var.
rustica. Planta 66:221-228.

Eschrich, W., B. Eschrich, and H. B. Currier. 1964.
Historadiographischen Nachweis von Calcium 45 im
Phloem von Cucurbita maxima. Planta 63:146—154.

 

Evert, R. F. 1963. Ontogeny and structure of the
secondary phloem in Pyrus malus. Amer. J. Bot.
50:8-37.

 

Faust, M. 1970. Calcium transport in apple trees.
Submitted to Plant Physiology. In press.

Gerard, C. J., and B. W. Hipp. 1968. Blossom-end rot

of "Chico" and "Chico Grande" Tomatoes. Proc.
Amer. Soc. Hort. Sci. 93:521-531.

152

11.

12.

13.

14.

15.

16.

17.

18.

19.

20.

21.

153

Green, D. W., and M. J. Bukovac. 1968. Redistribu-
tion of calcium in Phaseolus vulgaris L. Proc.
Amer. Soc. Hort. Sci. 93:368-378.

 

Ghoshen, Najati Saleh. 1962. Accumulation and re-
distribution of potassium and calcium in young
apple trees. Ph.D. thesis. University of Illinois.

Hoad, G. V., and A. J. Peel. 1965. Studies on the
movement of solutes between the sieve tubes and
surrounding tissues in willow. I. Interference
between solutes and rate of translocation measure-
ments. J. Expt. Bot. 16:433-51.

 

Jacoby, B. 1967. The effect of the roots on calcium
ascent in bean stems. Ann. Bot. N. S. 31:725-730.

Koontz, H. V., and R. E. Foote. 1966. Transpiration
and calcium deposition by unifoliate leaves of
Phaseolus vulgaris differing in maturity. Physiol.
Plantarum 19:313-321.

 

Kohl, Wilhelm. 1966. Die Calciumverteilung in Apfeln
und ihre Veranderung wahrend des Wachstums.
Doctoral Diss. Inst. Obstbau Univ. Bonn, Germany.
Also in Die Gartenbauwissenschaft 31:1966.

Lauchli, A. 1968. Untersuchungen mit der Rontgen-
microsonde fiber Verteilung und Transport von Ionen
in Pflanzengeweben. II. Ionentransport nach den
Fruchten von Pisum sativum. Planta: 137-149.

Maas, E. V. 1969. Calcium uptake by excised maize
roots and interactions with alkali cations.
Plant Physiol. 44:985-989.

Martin, D. 1967. 45Ca movement in apple trees.
Experiments in Tasmania 1960-1965. Field Sta.
Rec. 6:49-53.

 

Mason, T. G., and E. J. Maskell. 1931. Further
studies on transport in the cotton plant. I.
Preliminary observations on the transport of
phosphorus, potassium, and calcium. Ann. Bot.
45:125-173.

, , and E. Phillis. 1936. Further studies
on transport in the cotton plant. III. Concern-
ing the independence of solute movement in the
phloem. Ann. Bot. 50:23-58.

22.

23.

24.

25.

26.

27.

28.

29.

30.

31.

32.

154

Millikan, C. R., and B. C. Hanger. 1965. Effects of
chelation and of certain cations on the mobility
of foliar applied 45Ca in stock, broan bean, peas
and subterranean clover. Aust. J. Biol. Sci.
18:211-26.

, and . 1967. Redistribution of 45Ca in
Trifolium Subterraneum L. and Antivihinum Majus L.
Austr. J. Biol. Sci: 20:1119-1130.

 

 

 

, and . 1969. Movement of foliar-applied
215Ca in brussels sprouts. Aust. J. Biol. Sci.
22:545-58.

Moose, A. 1938. Chemical and spectroscopic analysis
of phloem exudate and parenchyma sap from several
species of plants. Plant Physiol. 13:365-380.

 

Norton, Robert Alan. 1954. Nutrition of the straw—
berry (Fragaria spp.). With special reference to
foliar absorption of radiophosphorus and calcium.
Ph.D. thesis, Michigan State University, East
Lansing, Michigan.

Peel, A. J., and P. E. Weatherly. 1956. Composition
of sieve-tube sap. Nature 184:1955-56.

Perring, M. A. 1968. Mineral composition of apples.
VII. The relationship between fruit composition
and some storage disorders. J. Sci. Fd. Agric.
19:186-192.

Pierce, E. C., and C. O. Appleman. 1943. Role of
ether soluble organic acids in cation-anion balance
in plants. Plant Physiol. 18:224-238.

 

Quinlan, J. D., and R. J. Weaver. 1969. Influence
of benzyladenine, leaf darkening, and ringing on
movement of 14C labeled assimilates into expanding
leaves of Vitis vinifera L. Plant Physiol. 443:
1247-1252.

 

 

Ringeoit, A., R. V. Rechenmann, and H. Veen. 1967.
Calcium movement in oat leaves measured by semi-
conductor detectors. Radiat. Bot. 7:81-90.

, G. Sauer, and A. J. Gielink. 1968. Phloem
transport of calcium in oat leaves. Planta
80:15-20.

33.

34.

35.

36.

37.

38.

155

Stout, P. R., and D. R. Hoagland. 1939. Upward and
lateral movement of salt in certain plants as indi-
cated by radio-active isotopes of potassium, sodium,
and phosphorus by roots. Am. J. Bot. 26:320-324.

Tammes, P. M. L., and J. Van Die. 1964. Studies on
phloem exudation from Yucca flaccida. Haw. Acta.
Bot. Neer. 13:76-83.

 

Wieneke, J., and N. R. Benson. 1966. Makroautoradio-
graphische Untersuchungen zur Translokation von
5Ca in Apfelfrfichte. Die Gartenbauwissenschaft
31:551-558.

Wiersum, L. K. 1951. Water transport in the xylem
as related to Ca uptake by ground nuts (Arachis
hypogeae L.) Plant and Soil. III. 2:160-168.

. 1966. Calcium content of fruits and storage
tissues in relation to the mode of water supply.
Acta. Bot. Neerlandica 15:406-448.

Ziegler, H. 1963. Verwendung von 45 calcium zur
Analyse der Stoffversorgung wachsender Frfichte.
Planta 60:41-45.

APPENDIX

156

TABLE A-l. Mineral content of Jonathan leaves (July
samples).

 

Survey 1968 Survey 1969

 

 

 

 

 

 

Standard Standard
Element Mean deviations Mean deviations
N (%) 1.89 0.22 1.99 0.16
P (%) 0.26 0.08 0.31 0.11
K (%) 1.17 0.24 1.29 0.22
Ca (%) 1.46 0.19 1.90 0.20
Mg (%) 0.40 0.03 0.24 0.04
Mn ppm 56.5 43.5 91 75
B ppm 33.0 4.6 42 5
Fe ppm 147 24 138 25
Cu ppm 12.5 4.9 18.6 5.2
Zn ppm 15.0 3.8 26.5 10.3
Al ppm 442 153 340 128

Graham Station 1968 Graham Station 1969

N (%) 1.76 0.20 1.86 0.19
P (%) 0.184 0.022 0.222 0.030
K (%) 1.23 0.13 1.30 0.17
Ca (%) 1.69 0.22 1.30 0.18
Mg (%) 0.34 0.05 0.41 0.07
Mn (ppm) 67.9 12.4 56.7 8.1
B (ppm) 32.7 1.3 35.8 3.2
Fe (ppm)263 23 248 42
Cu (ppm) 11.9 3.2 13.3 1.8
Zn (Ppm) 24.6 2.8 10.1 2.1
A1 (ppm)562 83 154 23

 

157

in fruit after storage, 1969 survey.

Mineral content of leaves (July samples) and
incidence of water core and internal breakdown

 

 

Internal p
Break- Water N K Mn B

Orchard Tree downa Coreb (%) (%) (ppm) (ppm)
1 l 10 6 2.04 1.32 62 47.2
2 1 0 2.02 1.32 70 49.0

3 7 5 1.90 1.32 95 52.7

4 3 0 1.90 1.56 45 41.7

2 l 0 0 1.92 1.42 73 39.2
2 0 0 1.78 1.42 51 35.4

3 0 0 1.82 1.28 103 47.8

4 l 0 1.90 1.46 68 41.0

3 l 47 38 1.94 0.80 366 34.1
2 89 87 1.86 0.86 268 32.9

3 57 50 2.02 0.96 328 35.4

4 60 38 1.80 1.12 270 32.9

4 l 32 9 1.78 1.80 84 47.8
2 l 0 1.92 1.80 81 44.1

3 1 l 2.00 1.66 79 41.7

4 2 l 2.00 1.24 56 34.8

5 l. 4 l 1.96 1.20 73 41.0
2 0 0 2.26 1.32 79 41.7

3 20 12 1.80 1.32 59 42.3

4 0 0 2.04 1.32 51 40.4

6 l 3 1 2.14 1.38 135 42.9
2 0 0 2.30 1.12 79 43.5

3 2 0 2.42 1.04 56 39.2

4 0 0 2.18 0.96 73 37.3

7 1 24 8 2.12 1.20 106 42.9
2 43 l 1.96 1.32 43 35.4

3 22 11 1.94 1.12 43 35.4

4 l 0 2.28 1.12 48 40.4

158

 

 

TABLE A-2. (Cont.)
Internal
Break— Water N K Mn B

Orchard Tree downa Coreb (%) (%) (ppm) (ppm)
8 l 14 3 1.86 1.32 37 46.6
2 1 2.08 1.00 45 34.1

3 0 1.96 1.08 62 41.7

4 0 1.80 1.24 40 38.5

9 1 5 1.80 1.20 89 35.4
2 18 9 1.90 1.24 73 36.7

3 l3 9 1.98 1.20 87 44.1

4 10 8 1.72 1.12 124 44.8

10 l 2 0 2.04 1.08 98 57.5
2 10 0 2.00 0.92 45 46.6

3 14 2 1.98 1.04 68 50.3

4 4 0 2.08 0.96 56 42.9

11 1 0 0 1.98 1.46 40 51.5
2 2 0 2.12 1.46 54 44.8

3 3 0 1.98 1.46 62 52.1

4 0 0 2.20 1.56 62 48.4

12 l 1 0 2.20 1.32 81 47.8
2 0 0 1.96 1.24 65 42.3

3 6 0 2.00 1.38 51 37.9

4 23 3 2.06 1.50 56 37.9

 

aThe sums of the number of fruit from the first

harvest with internal breakdown in samples examined

12/15/69 and 2/19/70.

b

and 2/19/70.

The sums of the number of fruit from the first
harvest with water core in samples examined 12/15/69

159

 

 

TABLE A-3. Mineral content of cortical tissue of fruit

(September samples), 1969 survey.
Orchard Tree N (%) K (%) Ca (%) Mn (ppm) B (ppm)

1 1 0.24 0.68 0.0275 0.408 20.0

2 0.20 0.56 0.0338 0.408 22.0

3 0.16 0.62 0.0338 0.438 23.6

4 0.24 0.82 0.0300 0.438 28.5

2 1 0.20 0.82 0.0275 0.266 17.6

2 0.16 0.66 0.0362 0.485 20.0

3 0.12 0.66 0.0250 0.266 20.0

4 0.06 0.62 0.0300 0.408 23.6

3 1 0.18 0.44 0.0200 0.485 16.8

2 0.18 0.50 0.0338 0.671 22.7

3 0.20 0.52 0.0200 0.485 16.3

4 0.18 0.52 0.0200 0.438 15.2

4 l 0.18 0.76 0.0440 0.798 22.7

2 0.20 0.76 0.0288 0.438 18.3

3 0.22 0.68 0.0300 0.438 14.3

4 0.20 0.62 0.0437 0.673 16.5

5 1 0.22 0.52 0.0338 0.408 22.7

2 0.30 0.76 0.0463 1.311 31.8

3 0.16 0.66 0.0288 0.313 35.6

4 0.20 0.68 0.0238 0.360 38.9

6 1 0.24 0.72 0.0288 0.438 18.1

2 0.34 0.66 0.0325 0.438 20.9

3 0.18 0.66 0.0262 0.313 22.7

4 0.28 0.60 0.0362 0.485 25.7

7 1 0.20 0.62 0.0338 0.625 15.0

2 0.14 0.66 0.0175 0.219 16.5

3 0.14 0.66 0.0200 0.171 13.2

4 0.20 0.68 0.0288 0.438 22.0

160

 

 

TABLE A-3. (cont.)
Orchard Tree N (%) K (%) Ca (%) Mn (ppm) B (ppm)
8 1 0.16 0.62 0.0213 0.171 29.0
2 0.16 0.62 0.0300 0.265 22.2
3 0.16 0.60 0.0338 0.485 30.9
4 0.14 0.62 0.0362 0.438 32.8
9 l 0.16 0.52 0.0200 0.313 20.0
2 0.18 0.56 0.0238 0.408 25.7
3 0.20 0.56 0.0326 0.625 24.9
4 0.14 0.52 0.0213 0.265 24.1
10 1 0.32 0.60 0.0262 0.360 28.5
2 0.22 0.62 0.0262 0.408 45.2
3 0.24 0.50 0.0200 0.313 29.6
4 0.34 0.62 0.0588 1.236 44.3
11 1 0.24 0.72 0.0188 0.219 32.5
2 0.28 0.72 0.0188 0.360 30.6
3 0.20 0.72 0.0188 0.171 45.2
4 0.24 0.72 0.0175 0.140 25.2
12 1 0.22 0.66 0.0248 0.265 16.8
2 0.20 0.66 0.0462 0.844 22.2
3 0.24 0.62 0.0650 1.125 26.8
4 0.80 0.72 0.0175 0.313 23.2

 

TABLE A- 4 .

161

Mineral content of leaves (June samples) and

incidence of water core and internal breakdown
in fruit after storage, 1968 survey.

 

 

O‘Chard Tree Siiik‘ 3:::§_ 28:25 (E) (E) (32m) (3pm)
1 1 9 20 1.88 1.46 51 29.6
2 1 2.06 1.32 63 35.4

3 3 15 2.02 1.42 51 36.0

4 24 43 5 1.92 2.18 40 35.4

2 1 1 1 2.08 1.50 84 37.3
2 o 0 1.90 1.70 48 31.6

3 7 12 4 1.92 1.56 67 32.5

4 9 17 0 2.12 1.66 65 32.2

3 1 1 1 3 1.86 1.04 234 33.5
2 o o o 1.80 0.66 166 29.6

3 3 s 11 1.90 1.24 182 29.8

4 o 1 12 1.88 1.16 202 32.9

4 1 0 2 1.38 1.70 26 32.9
2 0 1 1.36 1.66 40 37.3

3 4 4 1.68 1.86 37 30.9

4 0 8 10 1.46 1.38 37 31.6

5 1 1 1 2 1.68 1.24 40 32.2
2 1 5 17 1.64 1.42 54 32.9

3 0 o 19 1.54 1.32 48 39.2

4 6 7 6 1.64 1.46 48 34.1

6 1 1 1 0 2.08 1.32 59 21.8
2 4 4 1 2.04 1.16 62 25.1

3 1 1 o 2.12 1.38 40 23.8

4 2 2 0 1.88 1.16 43 22.4

162

 

 

TABLE A-4. (Cont.)

Orchard Tree ,3532k- 35:: 7 22:25 (2) (g) (Ppm) (ppm)
7 1 1 13 1.64 1.46 28 22.4
2 O 5 1.70 1.50 31 25.1

3 2 0 1.68 1.56 26 23.1

4 8 13 6 1.98 1.32 23 23.8

8 1 O l 1.95 1.08 34 23.8
2 O 3 1.78 1.08 31 23.1

3 12 33 9 1.72 1.12 26 23.8

4 1 5 18 1.94 0.96 20 21.1

9 1 21 50 14 1.96 0.96 79 21.1
2 11 20 0 2.00 1.08 62 21.1

3 8 14 3 2.14 1.04 89 23.8

4 10 23 3 1.94 0.92 76 21.8

10 1 0 15 2 2.26 0.96 45 23.8
2 0 18 7 2.38 0.86 87 29.0

3 0 16 6 2.28 0.88 45 24.4

4 5 32 14 2.18 0.88 51 23.8

11 1 0 0 0 2.13 1.56 34 23.4
2 10 17 1 2.29 1.70 45 29.0

3 0 0 O 1.91 1.46 54 30.3

4 0 0 0 1.99 1.38 45 27.0

12 1 0 0 1 2.40 1.38 45 23.1
2 O 1 O 2.30 1.32 45 23.8

3 O 0 O 1.96 1.56 43 21.8

4 O 0 O 2.08 1.56 48 23.8

 

aNumber of fruits from the 1968 survey out of Ca
storage with internal breakdown on 5/7/69.

b

examined 2/25/69, 3/18/69 and 5/7/69.

CNumber of fruits with water core in sample
examined 12/28/68.

Sum of number of fruits with internal breakdown

163

TABLE A-S. Mineral content of fruit (including peel and

core), 1968 survey.

 

 

N (% K (% Ca (% Mn (ppm B (ppm
Orchard Tree Sept.) Sept.) June) June) Sept.)
1 l 0.34 0.76 0.32 9 23.8
2 0.26 0.70 0.35 14 18.4
3 0.32 0.68 0.35 11 17.0
4 0.28 0.76 0.32 11 21.1
2 l 0.36 0.72 0.37 17 22.4
2 0.28 0.76 0.29 14 16.4
3 0.24 0.64 0.32 20 16.4
4 0.26 0.80 0.32 17 18.4
3 1 0.26 0.46 0.27 17 16.4
2 0.22 0.50 0.29 23 17.7
3 0.26 0.56 0.32 20 16.4
4 0.24 0.56 0.32 28 17.7
4 l 0.19 0.76 0.42 11 26.4
2 0.16 0.78 0.37 11 20.4
3 0.19 0.76 0.37 11 16.4
4 0.17 0.76 0.37 9 21.1
5 1 0.19 0.68 0.42 17 22.4
2 0.24 0.80 0.40 17 25.1
3 0.24 0.81 0.47 11 27.7
4 0.26 0.74 0.42 17 15.7
6 1 0.32 0.76 0.35 20 19.1
2 0.28 0.66 0.37 23 22.4
3 0.27 0.59 0.32 11 21.1
4 0.24 0.51 0.35 14 19.8
7 l 0.24 0.70 0.27 9 17.0
2 0.27 0.66 0.29 6 17.0
3 0.34 0.70 0.32 9 17.0
4 0.32 0.76 0.24 3 26.4

164

TABLE A-S. (Cont.)

 

 

N (% K (% Ca (% Mn (ppm B (ppm
Orchard Tree Sept.) Sept.) June) June) Sept.)
8 1 0.22 0.56 0.27 0 23.8
2 0.21 0.61 0.29 6 21.1
3 0.25 0.54 0.29 6 26.4
4 0.20 0.63 0.32 6 19.8
9 l 0.18 0.46 0.22 6 19.1
2 0.49 0.53 0.27 11 24.4
3 0.20 0.50 0.27 11 25.1
4 0.19 0.53 0.24 11 23.1
10 1 0.30 0.51 0.32 9 26.4
2 0.39 0.51 0.32 9 31.6
3 0.34 0.58 0.27 6 30.3
4 0.31 0.56 0.32 9 31.6
11 1 0.31 0.91 0.37 9 27.7
2 0.25 0.80 0.29 14 27.7
3 0.26 0.80 0.35 17 32.9
4 0.22 0.78 0.35 25.1
12 1 0.29 0.78 0.32 17.0
2 0.25 0.68 0.27 11 19.8
3 0.25 0.68 0.27 22.4
4 0.27 0.81 0.27 25.7

 

GQN STRTE UNI V

111911191112 11191 91191119111191 191111111111911191111111s