There are five groups of plant-growth-regulating compounds: auxin, gibberellin (GA), cytokinin, ethylene, and abscisic acid (ABA). For the most part, each group contains both naturally occurring hormones and synthetic substances

1. Plant Growth hormones

3. Hormones
•They are a especial type of proteins
that a living organism uses to
communicate different parts of the
body or trigger some
mechanism. Enzymes are other kind
of proteins which task is to destroy,
specifically, other proteins.

5. Control of stem Elongation
(auxin and gibberellic acid)
Initiation of flowering
(Flowering hormone from
leaves)
Growth of young fruits
(cytokinin's);
induction of fruit
ripening (ethylene)
Control of cell
division (cytokinin's
and gibberellic acid)
Stomatal closure
(abscisic acid)
Development of
abscission zone
(ethylene and auxin)
Gravitropism of roots
(auxin)
Hormonal Interaction
influence plant growth and
development

7. Auxins:
• Produced at the terminal or last buds in the plant, their job is to suppress lateral bud
growth.
• This ensures that a plant initially grows tall before it branches out to a more rounded
appearance.
• Auxins also stimulate root growth to keep the plant base secure.
• Promote stem elongation , adventitious root initiation and fruit growth inhibit axillary
bud outgrowth and leaf abscission

8. Auxin moves to the darker
side of the plant, causing
the cells there to grow
larger than corresponding
cells on the lighter side of
the plant.

9. Gibberellin Harmone:- (endogenous plant growth regulator)
“Gibberelin is a plant synthesis harmone that regulate the
development and growth of plant”
It also control the physiological process and function of
plant.
Present in young tissue, shoot, embryo, germinating seeds,
shout bud, etc.
Gibberellin (GA) is named as GA1, GA2, GA3…GAn depends
upon their type and order of discovery. There are more than
100 gibberellins reported. (GA3 - Gibberelin acid)

10. Discovery:-
First isolated from fungus disease
named ‘Gibbrella Fujikuroi’ in Japan
grown on rice causing the abnormal
growth like extra tall,thin,yellow
spotting,etc. Gibbrella Fujikuroi
discovered by ‘Kuro-Sawa’ the
Japanese Physiologist.

11. Application of Gibberelin:-
• Promote Stem elongation.
• Breaking seed & bud dormancy (seed germination).
• Increase size of leaves.
• Introduction of Parthenocarpy (development of fruit
without fertilization )
- also increase in size of seedless fruit.
• Increase yield (fruit size).
• Delay fruit mutuarity (ripening).
• Increase volatile oil ,content of Anethum Species.
• Promote vegetable & fruit growth.

13. • Plant Hormones
• Intercellular messenger molecules
• To control growth, development & control
the different functions in the plant
•Cytokinin (Adenine Derivatives):
• Cyto (cell) + Kinin (division) promote cell
division in the plant
• They Involve primarily in cell growth and
differentiation
• They are basically basic in nature

14. Types:
•Natural
•(Zeatin,dimethy
aminopurine,isopentanyl
aminopurine)
•Synthetic
•(kinetine, diphenyl urea)

15. Functions of Cytokinin:
Stimulate the cell division
Stimulate the Morphogenesis(stimulate the formation of stem and leaves)
Growth of lateral bud
Chlorophyll synthesis
It delay senescence(something bad for the plant e.g. untimely falling of foods, flowers by formation of protein).

16. Functions of Cytokinin:
• Stimulate the cell division
• Stimulate the Morphogenesis(stimulate
the formation of stem and leaves)
• Growth of lateral bud
• Chlorophyll synthesis
• It delay senescence(something bad for
the plant e.g. untimely falling of foods,
flowers by formation of protein).
•

17. Sites of Cytokinin Synthesis i.e.(examples):
• Primary site of synthesis root tips.
• High concentrations immature seeds and developing fruits
• Cytokinins extracted from coconut milk, Tomato juice
• Flowers and fruits of pear, plum
• Cambium tissues of Eucalyptus, Nicotina
• Immature fruits of Zea Mays, Musa sp.
• Root exudates of Sunflower
Uses:
• Used by farmers to increase the crops
• When applied to cotton seedlings, led to 5-10 % increase even in drought conditions.
• Plays a major role in plant pathogenesis by inducing resistance against certain disease-
causing bacteria.

18. Have you ever noticed that if you put a really ripe, brown banana right
next to a bunch of green bananas, the unripe bananas will ripen and
turn yellow much faster? How does that happen?
•Well, the brown banana is
communicating with the green
bananas using a hormone called
ethylene. Ethylene is a plant hormone
that affects ripening and rotting in
plants.

19. Ethylene
•Produced in most tissues under stress senescence or ripening
•Can I have some now actions in the development of
•Fruit ripening
•Leaf and flower sentescence
•Leaf and fruit abscission (control separation of plant part from the main
body)
•Floral gender determination in monoecious a species promote female

20. Experimentation with plant response to
ethanol commercial use
Muted Ethylene receptors Normal Etyelene receptors level

21. Introduction:
Plant hormone It is an naturally occurring compound in plants The
production of ABA is regulated by stress such as water loss and
freezing temperature It is often reflected as an inhibitory rather then
stimulatory Hormone It is involved in the closure of stomata, bud and
seed dormancy and is known to inhibit other hormonal actions.
---Acetic acid
is called stress hormones acid induced various responses in plants
against stress conditions it increase the tolerance of plants towards
various stressness it induces the climate of the stomata during water
stress it promotes seed dormancy in favorable conditions .

22. • Production:
• • abscisic acid produced in the
roots of the plants as well as the
terminal birds at the top of the
plant
• • It is synthesis in green fruits as
the beginning of the winter period
•• It translocate from the roots of
the leaves by The xylem.

23. Function of abscisic acid::
• Stem root growth inhibit stem and root growth not a value during
psychological stress for example draught water Logging
• Dormancy promotes bud and seed dormancy ..
• Flowering promotes flowering in short day plants and inhibits in long
day plants (Antaginistic to gibberelline.)
• Leaf senescence sometimes promote leaf senescence • Abscission
promotes abscission
.

24. • Closing of stomata. Promotes closing of stomata under conditions of water stress.
• Stress hormone. It induces various responses in plants against the stress
conditions. It induces the cleasure of the stomata during water stress