Use of Growth Regulator in Fruit Production
Use of Growth Regulator in Fruit Production
Defination of Growth Regulator:
Growth regulator may be defined as chemical substance, other than nutrient and vitamin regulate the growth of plant when applied in small quantities.
In term growth substance or auxin is often used to mean the same as growth regulators.
Types of Growth Regulators:
1. Auxin
2. Gibberellins
3. Cytokines
4. Ethylene
5. Inhibitors
6. Growth retardants.
1. Auxins:
Dr. Kogl and his co-workers in 1933 isolated auxin –‘a’ from human urine and auxin ‘b’ from corm germ oil. Afterwards physiological roles of auxin have been reported by many scientists. These auxin who are responsible for revolutionary changes in the field of horticulture.
Action:
1. Auxin transport – pola- basi- apex to base.
2. Cell elongation.
3. Promote root initiation.
4. Inhibits root elongation.
5. Delay leaf abscission.
6. Induce callus formation.
7. Restore apical dominance.
e.g. – 1. IAA (Indole Acetic Acid)
2. IBA (Indole Butyric Acid)
3. NAA (Naphthalene Acetic Acid)
4. 2, 4-D (2, 4 – Dichlorophenxy Acetic Acid)
5. 4-CPA (4-Chloropenoxy Acetic Acid).
2. Gibberellins:
In 1929 scientist ‘Yabata and Hayashi’ first isolated gibberellins from fungal culture. Since then number of gibberellins have been isolated from both the fungus and plants.
Action:
1. Promote growth (Specially those plants are genetically dwarf types).
2. Promote bolting and flowering.
3. Replace chilling requirements of plants and light requirements.
4. Promote seed germination and break dormancy.
5. Increase pollinations.
6. Increase cell elongation.
7. Induce maleness.
3. Cytokines:
The first Cyotkininn hormone in plant was identified by ‘Lethan and his co-workers’ from corn seeds which can stimulate cell division.
Actions:
1. Cell division.
2. Shoot initiation.
3. Breaking dormancy: promote seed germination.
4. Retard senescence: freeness’s of plants.
5. Promote hermaphrodite flower.e.g Grape.
6. Induce parthenocarpic and increase fruit size.
4. Ethylene:
A synthetic chemical known as Ethrel (Ethephon -2), Chloroethyl phosphoric acid (CEPA) which reduce ethylene when applied on plant.
Actions:
1. Apical dominance arrested.
2. Stimulate of lateral growth.
3. Promote abscission of leaves, flowers, and fruit.
4. Induction of flowering.
5. Helps in fruit ripening.
6. Promote rooting.
7. Helps in chlorophyll formation.
8. Promote seed germination.
9. Increase female flowers.
10. Breaks dormancy.
5. Growth retardants:
Slow cell division and cell elongation.
e.g. i) 2,4 DNC (2,4 Dichlorobenzyl ).
ii) CCC (Cycocel) and
iii) Alar.
Actions:
1. Regards stem elongation.
2. Prevents cell division.
3. Accelerate flower initiation.
4. Inhibits root development.
5. Inhibitors: Suppers the growth of plants.
Synthetic inhibitors:
1. MH- Maleic hydrazide.
2. TIBA- Tri- iodobenzoic acid.
Actions:
1. Accelerate the loss of chlorophyll.
2. Inhibits germination.
3. Induce flowering 9 by suppressing Vegative growth)
4. Increase the yield of tubers.
5. Induce male sterility.