1. Topic- Role of plant growth regulators in Vegetable Crops
Presenataion
Topic- Role of plant growth regulators in Vegetable Crops
Speaker
TInku Kumar Sharma
Roll Number
Venue-
Department of plant science (Horticulture)
BBAU, Lucknow

2. Plant Growth Regulator ?
An organic compound,
Can be natural or synthetic,
It modifies or controls one or more specific physiological processes within a plant but the sites of action and production are different.

3. Classification of PGR’s
Sr. No.
Growth regulator
Example 1
Auxins
IAA, IBA, NAA, 2,4-D 2
Gibberellins
Gibberellic acid 3
Cytokinins
Kinetin, Zeatin 4
Ethylene 5
Dormins
Abscissic Acid 6
Flowering hormones
Florigen, Anthesin, Vernalin 7
Miscellaneous natural sunstances
Cyclitols, Vitamins, Phytochrome, Traumatic substances etc. 8
Phenolic substances
Coumarin 9
Synthetic growth retardants
CCC, Phosphon D, Morphactins, Maleic
hydarzode (MH) etc.

4. Plant Growth Promoters Plant Growth inhibitors
Major classes of PGR’s
Auxins
Gibberellins
Cytokinins
Ethylene
Abscisic acid
Plant Growth Promoters
Plant Growth inhibitors

5. Plant Growth Promoters
Auxins
The word Auxins has been derived from a Greek word auxein- “to grow/increase”.
It was first isolated from human urine.
These are generally produced by the growing apex of stem and roots of the plants.
Types of Auxins
Natural Indole-3-Acetic acid (IAA)
Synthetic IBA, 2,4-D, NAA

6. Functions of Auxins Apical dominance Root initiation and development
Phototropism
Parthenocarpy
Inhibition of abscission layer
Used as weedicide
Flowering
Storage

7. Gibberellins
Gibberellins are named after the fungus Gibberella fujikuroi , which causes rice plants to grow abnormally tall (Kurosawa et al., 1930).
It produce in the embryos,roots and young leaves
More than 60 types of Gibberellins are known today.

8. Functions of Gibberellins
Stem elongation
Seed germination and Seedling growth
Breaking of seed dormancy
Promotes bolting & flowering – long day/cold requirement
Flowering and sex expression

9. Cytokinins They were first isolated from coconut milk.
Miller, Skoog and their coworkers isolated the growth factor responsible for cellular division from a DNA preparation calling it as Cytokinins (1950).
They are synthesized in root apex, endosperm of seeds, young fruits, where cell division takes place continuously.

10. Functions of Cytokinins
Promotes cell division, cell enlargement and cell differentiation (used in tissue culture).
They prevent aging of plants.
They inhibit apical dominance and help in growth of lateral buds.
Therefore it is also known as anti-Auxins.

11. Plant Growth Inhibitors
Ethylene
Ethylene is a colourless gaseous hormone
Found in ripening fruits, flowers and leaves and nodes of stem.
Synthesis of ethylene is inhibited by carbon dioxide and requires oxygen. 

12. Functions of Ethylene It induces ripening of fruits.
Promotes abscission and senescence of leaf, flowers etc.
In cells it only increases the width not the length.

13. Abscisic Acid
It is also known as dormins, which acts as anti-Gibberellins.
It is synthesized in leaves of wide variety of plants.
Responsible for closing stomata during drought conditions, hence acts as plant stress hormone.

14. Functions of Abscisic Acid
It induces dormancy of buds and seeds as opposed to Gibberellins, which breaks dormancy.
Involved with leaf and fruit abscission (fall).
It inhibits seed germination and development.
ABA also plays important role in controlling stomata opening and closing.

15. Commercial Use of PGR’s in Vegetable crops

16. List of plant growth regulators and their important uses in vegetable crops
Conc. (mg/l)
Method of application
Crops
Attributes affected
Cycocel (CCC)
Foliar spray
Cucurbits, tomato, okra
Flowering, sex expression, fruit yield
P-Chlorophenoxy Acetic acid (PCPA) 50
Tomato
Fruit set and Yield
Ethephon (CEPA)
Cucurbits, okra and tomato
Flowering, fruiting, sex expression and yield
2000
Post- harvest
Tomato, chillies
Fruit ripening
Gibberellic acid (GA) 10
Water melon, tomato
Sex expression, fruiting , yield
Indoleacetic acid (IAA)
10-15
Okra, tomato, brinjal,
Seed germination, fruit set and yield
Contd…

17. Naphthalene acetic acid (NAA)
0.2
Seedling roots
Tomato, brinjal, onion
Growth and yield
10-20
Foliar sprays
Chillies and tomato
Flower drop, fruit set and yield
25-30
Seed/ foliar
okra ,Tomato, brinjal, onion, cucurbits
Seed germination, growth and yield
Naphthoxyacetic acid (NOA)
25-100
Tomato, okra
Germination, growth and yield
Silver nitrate
500
Foliar spray
Cucumber
Induction of male flower in gyn, lines
Silver thiosulphate
400 -
Musk melon
2,3-5, tri-iodobenzoic acid (TIBA)
25-50
cucurbits
Flowering, sex expression and yield
Tricontanol 2
Chillies and peas
Fruit set and yield
Source :Chadha and Kalloo,1993

18. PGR’s provide an immediate effect Can be use for quality improvement
Conclusion
PGR’s provide an immediate effect
Can be use for quality improvement
Can be used for hybrid seed production
Can be used for long storage of produce .
Contd…