16576337-PHYTOHORMONES.ppt

PHYTOHORMONES

PRESENTED BY:- MEHREEN JAVERIA

HORMONESHORMONES Chemical that transfers information Chemical that transfers information

and instructions between cells in and instructions between cells in animals and plantsanimals and plants

Hormones act more slowly, and their Hormones act more slowly, and their effects typically are maintained over a effects typically are maintained over a longer period of time. longer period of time.

Required in very low concentration.Required in very low concentration. Synthesized at one part and Synthesized at one part and

translocated to another for their action.translocated to another for their action.

PHYTOHORMONESPHYTOHORMONES Also called Also called growth growth

hormoneshormones.. A hormone produced A hormone produced

naturally by naturally by plantsplants that activates or that activates or regulates their regulates their growth. growth.

The synthetic The synthetic equivalent used to equivalent used to promote growth in promote growth in cultivated plants are cultivated plants are called as called as growth growth regulatorsregulators..

Have promoting or Have promoting or inhibiting effect. inhibiting effect.

TYPESTYPES DifferentDifferent types:- types:-

AuxinAuxin GibberellinsGibberellins CytokininsCytokinins EthyleneEthylene Abscisic acidAbscisic acid Jasmonic acidJasmonic acid Other hormonesOther hormones

AUXINAUXIN Auxin (Gk. Auxin (Gk. auxein=auxein=to to

grow).grow). First to be discovered. First to be discovered. Name Auxin given by Name Auxin given by

WENT(1928).WENT(1928). First auxin isolated First auxin isolated

from human urine and from human urine and was named heteroauxin, was named heteroauxin, chemically it was indole chemically it was indole 3 acetic acid (IAA).3 acetic acid (IAA).

Weakly acidicWeakly acidic Capable of cell Capable of cell

elongation (shoots ).elongation (shoots ).

Heteroauxin found in humans Heteroauxin found in humans suffering from pellagra, a disease suffering from pellagra, a disease caused by deficiency of niacin caused by deficiency of niacin (vitamin B(vitamin B55).).

TYPESTYPES

Natural Auxins :-Natural Auxins :- PhytohormonesPhytohormones Synthesized in leaf primordia, shoot Synthesized in leaf primordia, shoot

apices and developing seeds.apices and developing seeds. Show polar movement.Show polar movement. Move slowly by diffusion from cell to cellMove slowly by diffusion from cell to cell Optimum concentration:Optimum concentration:

Shoots :10ppmShoots :10ppm Roots : 0.0001ppmRoots : 0.0001ppm

a tissue or organ in the earliest stage of embryonic development, found when the dividing cells in the fertilized ovum first differentiate .

ExamplesExamples : : IAA IAA 3 acetaldehyde3 acetaldehyde 4-chloro-idole 4-chloro-idole

acetic acidacetic acid

SyntheticSynthetic AuxinsAuxins :- :- Artificially made.Artificially made. Cause similar Cause similar

responses responses common to IAA.common to IAA.

Move in all Move in all directions.directions.

Eg:-Eg:- 2,4-D2,4-D IBA (Indole IBA (Indole

Butyric Acid)Butyric Acid) NAA (Naphthalene NAA (Naphthalene

Butyric Acid)Butyric Acid)

FUNCTIONSFUNCTIONS Cell enlargementCell enlargement Cell division in cambiumCell division in cambium Root growth (low conc.)Root growth (low conc.) Apical dominanceApical dominance Cause phototropismCause phototropism Parthenocarpic fruits Parthenocarpic fruits

(banana)(banana) Synthesis of ethyleneSynthesis of ethylene

( high conc. IAA) ( high conc. IAA) Respiration (stimulate)Respiration (stimulate)

USESUSES Eradication of weeds (2,4-D)Eradication of weeds (2,4-D) Rooting stem cuttings (IBA ,NAA)Rooting stem cuttings (IBA ,NAA) Parthenocarpy (grapes)Parthenocarpy (grapes) Flowering, plants like pineapple, Flowering, plants like pineapple,

litchi (NAA)litchi (NAA) Preventing pre harvest fruit drops of Preventing pre harvest fruit drops of

orange, apple ,tomato etc.(2,4-D)orange, apple ,tomato etc.(2,4-D) Prevention of falling of crop plants. Prevention of falling of crop plants.

(NAAM-Naphthalene acetamide)(NAAM-Naphthalene acetamide)

GIBBERELLINSGIBBERELLINS Isolated from Isolated from

Gibberlla fujikori Gibberlla fujikori by by Yabuta(1935).Yabuta(1935).

Weakly acidicWeakly acidic Cause cell elongation Cause cell elongation

of intact plant.of intact plant. Increase internodal Increase internodal

length of dwarfed length of dwarfed plantsplants

Synthesized in young Synthesized in young leaves near shoot tips, leaves near shoot tips, root tips etc.root tips etc.

NODE:the place on a plant stem where a leaf is attached or has been attached

They are synthesized from a They are synthesized from a precursor compound precursor compound mevalonic mevalonic acid acid (derived from acetyl co A).(derived from acetyl co A).

They are transported in plants by They are transported in plants by simple diffusion and also by simple diffusion and also by conducting channels.conducting channels.

TYPESTYPES

100 different types 100 different types have been have been identified.identified.

A single plant A single plant posses a no. of posses a no. of gibberellins.gibberellins.

They are termed as They are termed as GAGA11 (Gibberellic (Gibberellic acid), GAacid), GA22,GA,GA33,GA,GA44 and so on.and so on.

FUNCTIONSFUNCTIONS Stem and leaf growthStem and leaf growth Elongation of genetically dwarf plants (pea, Elongation of genetically dwarf plants (pea,

maize)maize) Bolting (cabbage): elongation of internodes.Bolting (cabbage): elongation of internodes. Induce floweringInduce flowering Seed germination (stimulate prod. of Seed germination (stimulate prod. of

hydrolytic enzymes)hydrolytic enzymes) Development of fruitsDevelopment of fruits Induce ParthenocarpyInduce Parthenocarpy Break dormancy Break dormancy

USESUSES

Fruit growth (size, bunch length in Fruit growth (size, bunch length in grapes)grapes)

Parthenocarpy (rice, pear)Parthenocarpy (rice, pear) Overcoming dormancyOvercoming dormancy Seed germination (lettuce, tobacco )Seed germination (lettuce, tobacco ) Delayed ripening (citrus fruits for Delayed ripening (citrus fruits for

storage)storage) Malt yield (increase the yield from Malt yield (increase the yield from

barley grains)barley grains)

CYTOKININSCYTOKININS They are basic in natureThey are basic in nature Promote cell division (cytokinesis) Promote cell division (cytokinesis) Work alone or with auxinWork alone or with auxin Discovered by Discovered by Miller Miller (1955) in coconut water(1955) in coconut water Skoog Skoog gave the term gave the term Cytokinins.Cytokinins. They are largely found in roots They are largely found in roots From roots they pass upward via xylemFrom roots they pass upward via xylem They are synthesized in endosperm of They are synthesized in endosperm of

seeds,growing embryosseeds,growing embryos and developing fruits.and developing fruits.

TYPESTYPES

First isolated was First isolated was ZEATIN (6-hydroxy ZEATIN (6-hydroxy 3-methyl trans, 2-3-methyl trans, 2-butenyl amino butenyl amino purine)purine)

Almost 18 types of Almost 18 types of Cytokinins are Cytokinins are knownknown

Miller discovered Miller discovered KinetinKinetin

KINETINKINETIN

6-FURFURYLAMINO-PURINE6-FURFURYLAMINO-PURINE

FUNCTIONSFUNCTIONS

Cell divisionCell division Cell elongationCell elongation Morphogenesis Delay in senescenceDelay in senescence Counter action of apical dominance.Counter action of apical dominance. Differentiation : Plastid etcDifferentiation : Plastid etc Increase resistance from diseasesIncrease resistance from diseases Stimulate enzyme activity especially Stimulate enzyme activity especially

photosynthesisphotosynthesis

SENESCENCESENESCENCE

AGEING OF LEAVESAGEING OF LEAVES

USESUSES

Tissue culture.Tissue culture. Increasing shelf life of fruits and Increasing shelf life of fruits and

vegetables.vegetables. Increasing resistance.Increasing resistance.

ETHYLENEETHYLENE

Gaseous hormoneGaseous hormone Stimulates transverse growthStimulates transverse growth Discovered by Discovered by CrockerCrocker (1935) (1935) Produced in plants from methionine.Produced in plants from methionine. Synthesized in all parts of plants.Synthesized in all parts of plants. High auxin conc. also causes High auxin conc. also causes

ethylene productionethylene production

FUNCTIONSFUNCTIONS

Transverse growthTransverse growth Inhibition of geotropismInhibition of geotropism Fruit ripeningFruit ripening Apical dominanceApical dominance Root initiation (low conc.)Root initiation (low conc.) Stimulate senescenceStimulate senescence Formation of ABAFormation of ABA Flowering (pineapple)Flowering (pineapple)

USESUSES

Ripening of fruits (ethylene lamps) Ripening of fruits (ethylene lamps) such as apple, banana, mango etcsuch as apple, banana, mango etc

Increase in number of fruits by Increase in number of fruits by increasing no. of female flowers increasing no. of female flowers especially in cucumberespecially in cucumber

Sprouting of storage organs such as Sprouting of storage organs such as tubers.tubers.

Sprouting of RhizomeSprouting of Rhizome

ABSCISIC ACIDABSCISIC ACID Mildly acidicMildly acidic Growth inhibitorGrowth inhibitor Counter acts all other hormonesCounter acts all other hormones First isolated by First isolated by AddicottAddicott (1963) (1963) He named it He named it Abscisin IIAbscisin II WareingWareing and and CornforthCornforth isolated a isolated a

substance which induced bud dormancy.substance which induced bud dormancy. They named it They named it Dormin.Dormin. Both abscisin and dormin later were Both abscisin and dormin later were

found to be same and named found to be same and named abscisic abscisic acid (ABA)acid (ABA)

Chemical structure of Chemical structure of ABAABA

FUNCTIONSFUNCTIONS Dormancy of buds and seedsDormancy of buds and seeds Abscission of flowers and fruitsAbscission of flowers and fruits Senescence of leaves by chlorophyll Senescence of leaves by chlorophyll

destructiondestruction Stomata closure ( during stress, prevents Stomata closure ( during stress, prevents

transpiration)transpiration) Inhibition of germinationInhibition of germination Delays floweringDelays flowering Tuberization in potato.Tuberization in potato. Enhances rooting Enhances rooting Controlled growth by checking activities of Controlled growth by checking activities of

other hormonesother hormones

tiny pore in the outer layer (epidermis) of a plant leaf or stem that controls the passing of water vapour and other gases into and out of the plant.

the natural process by which leaves or other parts are shed from a plant

USESUSES

Antitranspirant Antitranspirant Promote rooting of stem cuttingsPromote rooting of stem cuttings Prolongs dormancy of buds, seeds Prolongs dormancy of buds, seeds

and storage organsand storage organs Induce flowering Induce flowering

JASMONIC ACIDJASMONIC ACID

3-Oxo-2-pentenyl-3-Oxo-2-pentenyl-cyclopentaneacetic cyclopentaneacetic acidacid

It is biosynthesized It is biosynthesized from from linolenic linolenic acidacid

A member of the A member of the jasmonate class of class of plant hormonesplant hormones..

FUNCTIONSFUNCTIONS Growth inhibition, Growth inhibition, Senescence Senescence Leaf Abscission Leaf Abscission Tuber formation in potatoes, yams, and Tuber formation in potatoes, yams, and

onions.onions. It has an important role in response to It has an important role in response to

woundingwounding of plants and of plants and resistanceresistance. . When plants are attacked by insects, they When plants are attacked by insects, they respond by releasing JA, which inhibits respond by releasing JA, which inhibits the insects' ability to digest proteinthe insects' ability to digest protein

OTHER HORMONESOTHER HORMONES BrassinolidesBrassinolides ::Plant steroids chemically similar to Plant steroids chemically similar to

animal steroid hormones. First isolated from pollen animal steroid hormones. First isolated from pollen of the mustard family. They promote cell elongation of the mustard family. They promote cell elongation and cell division, differentiation of xylem tissues, and cell division, differentiation of xylem tissues, and inhibit leaf abscission.Plants found deficient in and inhibit leaf abscission.Plants found deficient in brassinolides suffer from brassinolides suffer from dwarfismdwarfism. .

Salicylic acidSalicylic acid ::In some plants activates genes that In some plants activates genes that assist in the defense against pathogenic invaders.assist in the defense against pathogenic invaders.

SysteminSystemin :: A polypeptide consisting of 18 amino A polypeptide consisting of 18 amino acids, functions as a long-distance signal to acids, functions as a long-distance signal to activate chemical defenses against herbivores. . activate chemical defenses against herbivores. .

Strigolactones:Strigolactones: Implicated in inhibition of shoot Implicated in inhibition of shoot branching.branching.

OTHER HORMONESOTHER HORMONES

BIBLIOGRAPHYBIBLIOGRAPHY

http://en. wikipedia . orghttp://en. wikipedia . org P.K.Garg, J.P.Sharma ; Biology; 2007; P.K.Garg, J.P.Sharma ; Biology; 2007;

Laxmi Publications.Laxmi Publications.

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