Plant Growth Regulator
- 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….