The document is an assignment submitted by Brahmbhatt Jay H on plant growth regulators and their role in vegetable crop production. It discusses various types of plant growth regulators including auxins, gibberellins, cytokinins, abscisic acid, ethylene, morphactins, anti-transpirants, anti-auxins, ripening retardants, and plant stimulants. It provides details on their functions, examples, and effects on plant growth and development processes.

1. WELCOME
Submitted to:-
Shri J.R. Vadodaria
Associate.Professor
H.O.D of Veg. science
College of Horticulture
SDAU, Jagudan
Submitted by:-
Brahmbhatt Jay H.
M.Sc.Horticulture

2. An Assignment
On
“Plant growth regulators in relation
To Vegetable production ;Role and mode of
Action of Morphactins , antitranspirants ,
anti-auxins , Ripening retardant and Plant
Stimulants in Vegetable crop Production”
Course No.: VSC-504
Course Title:-Growth And
Development of Vegetable crops

3. History of Growth Regulators
 Auxin was the first hormone to be
discovered in plant and at one time
considered to be only naturally occurring
plant growth hormone.
 Three types of plant hormones Auxins,
Gibberellins and Cytokinins and these
were discovered in the early decades in
thetwentieth century in 1930`s and in
1960`s respectively.

4. INTRODUCTION
 A Growth Regulator is
 An organic compound,
 Can be natural or synthatic,
 It modifies or controls one or more specific
physiological processes within a plant but the sites of
action and production are different.
 If the coumpound is produced within the plant, it is
called as plant hormone.
 Both internal plant hormones and lab created hormones
are called plant growth regulators.

5. What is Plant Growth Regulators?
 Plant growth regulators means, any
substance or mixture of substances
intended, through physiological action, to
accelerate or retard the rate of growth or
maturation, or otherwise alter the behavior
of plants or their produce.
 Additionally, plant regulators are
characterized by their low rates of
application; high application rates of the
same compounds often are considered
herbicidal. e.g 2-4 D

6. Cont…
 The growth of plants is regulated by certain
chemical substances, which are synthesized by the
plant in very small quantities.
 These substances are formed in one tissue or
organ of the plant and are then transported to
other sites where they produce specific effects on
growth and development. They are referred to as
plant hormones.
 Plant hormones are organic compounds which are
capable of promotion, inhibition or modification
of growth.
 The plant hormones are also known as growth
factors, growth hormones, growth substances,
growth regulators or phytohormones.

7. Two types of hormone
 Plant hormone: If the compound is produced
within the plant it is called a plant hormone.
 Synthetic Hormones: Synthetic chemical
compounds that mimic the activity of hormones
produced in the body, but differ in structure from
naturally occurring hormones.
 Phytohormones are grouped into 2 main types –
 Growth promoters have a positive effect on a
process and thus promote it.
 The growth inhibitors have a negative effect and
cause inhibition.

8. Major classes of plant growth regulators
1. Auxin
2. Gibberellins
3. Cytokinin
4. Abscisic acid
5. Ethylene

9. Auxin
 Growth promoting chemicals.
 Promote cell division and cell elongation.
 Primary plant auxin is indole acetic acid (IAA)
 Common synthetic forms of auxins are indole butyric acid (IBA)
and naphthalene acetic acid (NAA)
 Useful in phototropism, geotropism, apical dominance, and root
formation.
 Phototropism- plant growth toward a light source.
 Geotropism- plant growth in response to gravitational forces.
 Apical dominance- terminal buds prevent the development of
lateral buds on plant stem.

10. Gibberellins
 Also known as Gibberellic acid or GA
 Growth promoting chemicals
 Stimulate stem growth through cell
elongation and cell division
 Commercial supplies obtained from
the
fungus Gibberella fujikuroi

11. Cytokinins
 Promote cell division and delay leaf
aging
 Used as a growth promoter in tissue
culture
 Slows the process of senescence
(biological aging) by preventing the
breakdown of chlorophyll in leaves

12. Abscisic acid (ABA)
 Only natural plant growth inhibitor.
 Growth inhibitor that closes the stomates of
plants under water stress.
 Counteracts the effects of auxins and
gibberellins.
 Cycocel and B-Nine are two synthetic ABA type
growth inhibitors commonly used.

13. Ethylene
 Gas that forms in tissue undergoing stress.
 Important in the fruit-ripening process
and early petal drop of flowers.

14. MORPHACTINS
 Defination: Morphactins are the group of
substances which act on morphogenesis and
modulate the expression of plants.
 Chemically, they are the derivates of fluorine
compounds.
 Fluorine - inactive, but the addition of COOH
group in the 9th position makes it active.

15. Examples
 Chloroflurenol
 Flurenol
 Methyl benzilate
 Methyl chloroflurenol
 Methyl dichloroflurenol

16. Effects of morphactins
 Exhibit both synergistic and antagonistic
effectsdepends upon the relative
concentrations.
 They inhibit seed germination, sprouting,
growth of seedling and internode
elongation.
 They depolarize cell division which
probably leads to distorted
morphogenesis.

17. Cont…
 Very effective in inducing lateral bud
development, so tillering will be profuse.
 Some morphactins stimulate flowering in
certain short day plants.
 Resemble ABA in inducing seed
dormancy, bud dormancy and suppressing
stem elongation.
 Most of their effects can be reversed by
GA3 treatment.

18. Role of Morphactines
 Seed germination – inhibition.
 Growth of seedlings –inhibit.
 Stem elongation –dwarfing effect.

19. Anti-transpirants
 The term anti-transpirant is used to
designate.
 Any material applied to plants for the
purpose of retarding transpiration.
 Useful for reducing transplantation shock
of nursery plants (Horticultural plants).
 Applied to transpiring plant surfaces for
reducing water loss from the plant.

20. Types of anti transpirants
 1. Stomatal closing type :
 Fungicides like phenyl mercuric acetate (PMA)
and herbicides like Atrazine in lower
concentration serve as anti transpirants by
inducing stomatal closing.
 These reduce the photosynthesis.
 PMA was found to decrease transpiration than
photosynthesis.
 ABA induces closure of stomata.

21. 2. Film forming type
 Plastic and waxy material which form a
thin film on the leaf surface.
 Results in reduction of transpiration rate
and photosynthesis.
Examples:
 Silicone oils
 Ethyl alcohol
 Polyvinyl chloride
 Polyethylene, polypropylene

22. 3.Reflectance type
 White materials which form a coating on the
leaves and increase the leaf reflectance (albedo).
 Examples:
 Kaoline @ 5% spray reduces transpiration loss
 Diatomaceous earth (Celite)
 Hydrated lime,
 Calcium carbonate,
 Magnesium carbonate,
 Zinc sulphate

23. Features of anti-transpirants
 Non toxic
 Non permanent damage to stomata mechanism.
 Specific effects on guard cells but not to other
cells.
 Effect on stomata should persist at least for one
week.
 Chemical or material should be cheap and
readily available.

24. Cont…
 Phenyl mercuric acetate at 35 ppm, kaolinite at
5% were sprayed on onion seedlings(Arka
Pragathi, Arka Niketan, Arka Kalyan and Pusa
Red) 30, 50, 70 or 90 days after transplanting
and Irrigation was with held a week before
spraying.
 Anti-transpirants cause 27 to 40% stomatal
closure and reduction varied from 22 to 56%
depend on cultivars.
 kaolinite treatment was most effective in
reducing water stress and stomatal closure.

25. Anti-auxins
 These are chemicals which inhibit the
action of auxins
 They closely resembles auxin but lacks at
least one requirement for activity
 Inhibit the effects of auxin
 Synthetic chemical derived from α-p-
choloro phenoxy iso-butyric acid (PCIB).

26. Examples
 2, 3, 5 tri iodo benzoic acid (TIBA)
 Napthyl thalamic acid (NPA)
 Clofibric acid
 4,4,4-trifluoro-3-(indole-3-)butyric acid
(TFIBA)
 Naphthyl-methyl-thio propionic acid
 m-tolyl phthalamic acid

27. Ripening Retardant
 Any kind of Agent or Factor which
inhibit process of Ripening.
 The plant growth retardants are
synthetic substances, which inhibit,
for a period of time, the elongation of
stem and shoots, without irreversible
blocking the vital metabolic and
developmental processes in plants.

28. Examples
 Dialkyl amino ethyl amides
 2-chloroethylphosphonic acid (CEPA)

29. Plant Stimulants
 A plant stimulant is any substances or
factors applied to plant, which stimulate
growth and development of plants.
Examples
 Benzyl adenine
 NAA
 2-4-D
 IBA
 2 -4 -5 T
etc….