Plant Hormone its typess and its function

1. PLANT HORMONE
• Plant Hormone is known as
phytohormone
• Plant Hormones are the organic
compound (inter cellular messanger)
Plant Growth Regulates(PGR)
1.Native Substance (Endogenous)
2.Synthetic Substance(Exogenous)

2. CLASS OF PHYTOHORMONES(PLANT
HORMONE)
1. Auxin
2. Cytokinesis
3. Gibberellins
4. Abscisic Acid
5. Ethylene

3. Role of Plant Growth Regulates(PGR)
• Regulate Cell Division & Enlargment
• Cell Differentiation
• Senconce(ability of growth)
• Dormancy
• Ripening of Fruit
• In Plant Tissue Culture

4. PLANT GROWTH PROMOTER
1. AUXIN
2. GIBBERELLINE
3. CYTOKININ
• THESE THREE HORMONES ARE KNOWN AS
PLANT GROWTH PROMOTER
• PROMOTE CELL DIVISION , CELL ENLARGMENT,
FLOWERING, FRUTING,SEED FORMATION.

5. AUXIN
GREEK WORDS “AUXIN” MEANS ‘TO GROW”
NATURAL AUXIN
Eg:-
(IAA):- Indole-3-Acetic
Acid
SYNTHETIC AUXIN
Eg:-
(IBA):-Indole-3-butyric Acid
(NAA):-Nepthyl Acetic Acid
(2,4,D):-2,4,dichlonoxy acetic
Acid

6. FUNCTION OF AUXIN
• Stimulate Internodes elongation
• Apical(Apex) Dominance
• Promote Abscission(Arrangment or sepreation of plant
part)eg:- older leaves, fruit
• Diffrentiation of vasculal tissue(xylem,phloem)
• Stimulates Root initiation on stem cutting
• Adventetious rooting in tissue culture
• Delay Senescence
• Tropistic response of bending in response to gravity & light

7. Application Of Auxin
1. Vegetative Propagation
(Rooting from stem cutting)
(IAA) eg:- papaya, coffee
2. Parthenocarpy:- Fruit Development
(with fertilization development, no seed)
3. Herbicide:- selection weed Kills
(2,4 D)
4. Plant Tissue Culture

8. CYTOKININ
• Cyto(Cell) + Kinin(Division)
• Promote cell Division
TYPES
1. NATURAL:-
eg:- Zeatin, N6 dimethyl
aminopurine,Isopentonyl aminopurine
2. SENTHETIC:-
eg:-Kinetin , N,N diphenyl Urea

9. FUNCTION OF CYTOKININ
• Found in Young & actively dividing tissue
• Stimulates cell division
• Stimulates Morphogenesis (growth of lateral bud)
• Leaf Expension
• Chlorophyll Synthesis
• Delay Senescence (delay aging)
• Development of embryo during seed formation
• Inhance The Stomatal opening in some species
• Seed germination

10. APPLICATION OF CYTOKININ
• Induce Cell Divison in Plant Tissue Culture
• Shoot inititation in tissue culture & release of
lateral bud dormancy
• Growth Of vegetable & yield
• Break dormancy of Seed

11. GIBBERELLINES
• Present In young tissue , root, Embryo ,
germinating Seeds , Shoot Bud etc.
• Named as GA , GA2 , GA3 , …… Gan
• GA3:- Gibberllic Acid
• First discovered from fungus , isolated from
Gibbrella Fujikuraoi ( by KURO-SAWA-
Japanese Phyisologist)grown on rice

12. APPLICATION OF GIBBERELLINS
• Promote Stem elongation
• Breaking Seed & Bud dormancy (seed
Germination )
• Increase in size of leaves
• Induction Of Parthenocarpy (Seedless fruit
develpment)
• Delay Senescence in leaves & Citrus Food
• Promote Bolting & flowering long day plants

13. ETHYLENE
• Simple organic molecule present in the form
of gas (gaseous growth regulater)
• Also Known as volatile hormone
• Work as Inhibitor
• Formula :- C2H4
• Present is ripening fruit , flower , stom, root,
tubers, seed , leaf etc.

14. • Discovery:-
Gane(1934) found that agas evolved frrom ripe
apple can also effect the rippening of green
apple & foud that it was Ethyline gas .
• Crocker reconised it as plant hormone (1935)

15. FUNCTION OF ETHYLENE
• Fruit ripening
• Leaf Abscission (sepration)
• Supress stem & roof elongation
• Stimulates Flower & leaf sonesense
• Breaking Dormancy
• Stem Swalling
• Ethylene + Auxin = Supress letral bud formation
• Stimulation of Latex flow(white fluid) in rubber tree
• Flower Opening & Flower Petel Discoluriation

16. ABSCISIC ACID(ABA)
• Natural Plant growth Inhibitor
• Produced by aging leaves & Fruit & when
plants are Stressed(“Stress Hormone” also
called “Dormin’)
• Discovery :- Addicott & associates(1963) first
isolated Abscisin-I and Abscisin-II(Known as
“Abscisic Acid”) from cotton balls
• Osborne found it in Senescent leaves

17. FUNCTION OF ABISCISIC ACID(ABA)
• Abscission of different Organ (Leaves, Fruit, Flower
etc.)
• Seed and Bud Dormancy
• Inhibit Gibberellin Synthesis of α amylase & other
hydrolytic Enzyme ( counter effect of Gibberellin)
• ABA enhance in stress condition (water deficiency,
injurly droght, flooding, Freezing tempreature.
• Reverse the effect of other growth stimulating
hormone