Growth: Vital process which brings about a permanent change in any plant or its part with respect to its size, form, weight and volume Differentiation: refers to qualitative changes that accompany growth. It leads to morphological and functional changes of plants Development: refers to sum of all the changes that an organism goes through in the life cycle－from germination of the seed upto senescence

1. “Physiology of growth and development of
pome and stone fruits”
Dr Jahangeer Ahmad Baba

2. Growth and development
 Growth: Vital process which brings about a permanent
change in any plant or its part with respect to its size,
form, weight and volume
 Differentiation: refers to qualitative changes that
accompany growth. It leads to morphological and
functional changes of plants
 Development: refers to sum of all the changes that
an organism goes through in the life cycle－from
germination of the seed upto senescence

3. Growth
Quantitative
Number, size,
and volume
increase
Differentiation
Qualitative
Emergence of
specialized
body parts

4. Development

5. Differentiation occurs at various levels. During the process of
differentiation, volume almost remains steady but there is
change in morphology and functioning
Organs Tissues Cells Molecules
Root
Stem
Leaf
Flower
Fruit
Conductive
Mechanic
Absorptive
Aerenchyma
storage
Xylem
Phloem
Root hairs
Genes
Proteins
Enzymes
Eye Microscope
Electron
microscope
Molecular
biology
Differentiation

6. Growth
Cell Division
Cell
Enlargement
Cell
Differentiation

7. Cell Division
Meristematic Cells
Primary
Shoot Apical Meristem
Root Apical Meristem
Secondary
Axillary Buds
Vascular Cambium
Cork Cambium
Pericycle (root)

8. Cell Division during fruit development
 There are 2 million cells in the flesh of apple few
days after anthesis and they require 21
doublings of cell number
 There are approximately 40 million cells in the
flesh of the fruit at harvesting stage
 Most of the post anthesis cell divisions occur in
first few weeks after bloom, but as long as
100 days in some cases

9. Duration of Cell Division in the Flesh of various Fruits
Fruit Duration After Blossom References
Apple 3-4 Weeks Bain and Robertson, 1951
Tetiey, 1931
Tukey and Young, 1912
Pear Early var. 25-30 days
Late var. 45 days
Poyama and Hayashi, 1957
Peach 1 month Reeve, 1959
Plum 4 Weeks Sterling, 1953
Cherry 10 days Tukey and Young, 1939
Avocado Until harvest Schroeder, 1953

10. Cell Enlargement
Begins soon after pollination continues through
cell division stage and then at diminishing rate
until harvest
Adjacent to Meristematic region
H2O Uptake
Turgor Pressure
Cell Wall Loosening
New cell walls are formed

11. Factors that tend to increase or decrease cell size
Increase cell size Decrease cell size
Few cells per fruit
Light bloom and set
Adequate soil moisture
Strong fruiting spurs
Centre bloom fruits
Excess nitrogen
High leaf fruit ratio
Healthy leaves
Excessive chemical or hand thinning
Many cells per fruit
Heavy bloom and set
inadequate soil moisture
weak fruiting spurs
side bloom fruits
Low nitrogen
Low leaf fruit ratio
Chlorotic / diseased leaves
Moderate or no thinning

12. Types of Growth
1. Determinate
Terminal shoot apex flowers
2. Indeterminate
Axillary buds flower
Terminal buds vegetative
3. Monocarpic
Flower once then die e.g. bamboo
4. Polycarpic
Flower repeatedly over several seasons

13. Fruit Development Stages
 Cell division
o Predominates after bloom
o Small fruited crops generally have a shorter period
of cell division
o Extended by some chemical thinners (BA, BAP)
 Pit hardening (stone fruits)
o Lignification of endocarp
 Cell enlargement
o Predominates later in fruit development (and
after pit hardening in stone fruit)
 Fruit maturation
o Final weeks (days) of fruit development

16. Factors influencing plant growth
1) Light
2) Temp.
3) Water
4) Minerals
5) Growth hormones
6) others

17. GENETIC FACTORS AFFECTING GROWTH AND
DEVELOPMENT
 DNA directs growth and differentiation
– Enzymes catalyze biochemical reactions
 Structural genes
– Genes involved in protein synthesis
 Operator genes
– Regulate structural genes
 Regulatory genes
– Regulate operator genes

18. Plant growth correlation
The growth among the different organs in a
whole plant coordinates and inhibits each
other, which is called the plant growth
correlation.

19. Role of Root-shoot ratio in fruit growth
 Root-shoot ratio is an index for the coordination
between root and shoot.
 Factors influencing root-shoot ratio and its regulation:
(1) Soil water content↓，the ratio↑
(2) Regulation with nutrition
• N↑, the ratio↓；N↓， the ratio ↑
(Leaf vegetable applied with heavy N)
• P and K↑ the ratio ↑
(Tuber root applied with much P and K)
(3) Sufficient light ↑ the ratio ↑

21. Mean expansion rates [10–40 DAFB] and mean harvest weight of fruit on trees
subjected to four controlled temperature regimes from 10 to 40 DAFB.
Cultivar Maximum/Minimum Temp. (0c)
Fruit expansion rate (mm.d–1)
13/3 16/6 19/9 22/12
Delicious 0.25 0.44 0.71 0.91
Golden
Delicious
0.21 0.42 0.63 0.82
Fuji 0.25 0.52 0.77 0.94
Harvested fruit weight (g)
Delicious 153 157 224 219
Golden
Delicious
112 132 171 186
Fuji 178 192 194 199
[Warrington et al., 2009]

22. Balance between Vegetative and Reproductive
growth
 The better vegetation promotes reproduction and
the poorer vegetation results in poorer reproduction
 Over-vegetation inhibits reproduction. Overgrowth
often gives rise to late flowering, bad setting, fruit
falling and yield decreasing.
 Over-reproduction reduces the vegetative organ
development and leads to premature plant
deterioration.

23. Fruit shape
Fruit length is negatively correlated with temperature
Hot days and warm nights result in oblate/flat fruits
Warm days and cool nights produce conical elongated fruits

25. Influence of crop load on fruit growth
and development
 Increasing leaf-fruit ratio (20-40 leaves/fruit) by thinning causes
remaining fruits to be larger, although not in direct proportion to
increase in number of leaves per fruit
 Early thinning helps to stimulate floral initiation for next year’s crop on
Cultivars that tend to be biennial by removing young embryos that
produce FBD inhibitors
 Apples initiate flower buds early, hence thinning must be done earlier
for good return bloom; and in pear floral initiation occurs later, thinning
can aid even upto later stages

26. Fruit Set Required for Commercial Crop
Large fruited crops 2 to 25%
o Apple: 2-8%
o Pear: 3-11%
o Peach: 15-20%
o Plum: 3-10%
o Apricot: 20-25%
Small fruited crops 40 -100%
o Almond: 20-100%
o Cherry: 20-75%
o Grape: 30-70%
o Kiwi: 95-100%

27. Fruit Thinning
 Disadvantage
– Reduce fruit yield
 Advantages
– Increase fruit size
 Other Advantages
Stimulate floral initiation
Avoid alternate bearing
Increase leaf to fruit ratio
Increase fruit color/quality
Reduce limb breakage
Improve plant health

29. Parameter Golden Delicious Red Chief
Standard
load
High load Standard load High load
Fruit weight (g) 214.4 a 161.1 b 183.1 a 132.6 b
Fruit size (mm) 78.10 a 70.04 b 73.73 a 65.14 b
TSS (Brix) 13.67 a 14.40 b 11.63 a 12.14 b
Flesh firmness
(kg/cm2)
7.03 a 7.79 b 7.65 a 8.34 b
Effects of crop load on quality parameters of apple fruits picked
from ‘Golden Delicious’ and ‘Red Chief’ trees carrying standard
and high crop load
[Robert et al., 2006]

30. Percentage of increase in volume of fruit in relation to increase in leaf area
on ringed branches of different varieties of Apple
Increase in leaves per fruit Percentage of increase in volume of fruit
Delicious York
Imperial
Baldwin Jonathan Average
From To Per cent
5 10 100 93.3 72.2 57.0 47.6 56.4
10 20 100 56.9 110.1 78.2 80.4 71.5
20 30 50 26.8 15.0 2.9 27.5 15.9
30 50 67 9.3 8.0 7.1 1.7 10.9
50 75 50 29.2 5.0 9.8 2.6 11.2
[Haller and Magness, 1999]

32. Relationship of seed number per fruit in mature Delicious apples to fruit
diameter, occurrence of senescent breakdown after storage and mineral
composition.
Seeds per
fruit
Fruit diameter
(mm)
Ca (ppm) Mg (ppm) Fruits that
developed
senescent
breakdown (%)
0-1 67 174 284 23
2-3 70 208 278 18
4-5 71 215 279 13
6-7 72 223 280 11
8-9 74 228 283 8
[Bramlage et al., 2009]

36. Role of PGR’S in fruit growth and development
1. Endogenous (Hormones)
a) Substance produced by a plant that affects the
pattern of growth and development.
b) Production by the plant is regulated by the
environment.
2. Exogenous (Regulators)
a) Substance applied to the plant that alters growth
and development in the same way as the
endogenous substances do.
b) May be the same or different chemically from the
endogenous substance

37. Primary
Auxins
Cytokinins
Gibberellins
Abscisic
Acid
Ethylene

38. Secondary
Or
Newly discovered
Jasmonic Acid
Brassinisteroids
Juglone
Salicyclic acid
Polyamines

39. Auxin Action
Mechanism of Action
Bind Receptor Protein Plasma membrane
Transport into cell
Activate ATPase in Plasma membrane
H+ ion extrusion
acidify cell wall
break hemi-cellulose-pectin bonds
cellulose microfibrils slide apart
cell enlarges

40. Fig. 39-8
Cross-linking
polysaccharides
Cellulose
microfibril
Cell wall
becomes
more acidic.
2
1 Auxin
increases
proton pump
activity.
Cell wall–loosening
enzymes
Expansin
Expansins separate
microfibrils from cross-
linking polysaccharides.
3
4
5
CELL WALL
Cleaving allows
microfibrils to slide.
CYTOPLASM
Plasma membrane
H2O
Cell
wallPlasma
membrane
Nucleus Cytoplasm
Vacuole
Cell can elongate.

41. Auxin Responses
Cell Enlargement
Shoot Growth
Internodes
Tubers
Bulbs
Root Growth
Storage Roots
Adventitious Roots
Fruit Growth
Strawberry - Receptacle enlargement
Apical Dominance
Auxin: Cytokinin Ratio
High - Dormant Axillary Buds
Low - Axillary Bud Growth

42. Importance of seeds-the source of auxins

43. Class Apple Strawberry Arabidopsis
ABP1 2 1 1
TIRI/AFB 8 4 5
ARF 37 18 23
Aux/IAA 40 26 29
PIN 11 9 8
GH3 (group 11) 15 9 10
Number of auxin related genes in apple compared
to strawberry and Arabidopsis
Devoghalaere et al. 2012

45. Cytokinins
 Responses
 Stimulate Cell Division
 Apical Dominance
 High Auxin in Shoot Apex
 High Cytokinin in Root Apex

46. Gibberellins
 Responses
Cell Elongation
Dwarf cultivars
Dwarfing rootstocks
apples, pears, peaches
height from roots
fruit quality from scion
Seed Dormancy
High ABA
Reversed by GA application
Synthesis of GA by embryo

47. Ethylene
Responses
Plays a role in fruit ripening
Promotes abscission (shedding of leaves, flowers and fruit)
Triggers enzymes that promote fruit loosening from trees
o Auxin prevents abscission (prevents pre-harvest)
o High concentration does the opposite

48. Abscisic Acid
Responses
Dormancy Maintenance
(high levels in dormant seed and buds)
Drought Resistance
(causes stomatal closure)