Question
Write an account of auxins as growth regulators.
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Answer
- Auxins are plant growth regulators produced naturally by plants.
- They are weak organic acids capable of promoting cell elongation during the growth of stem and root.
- Auxins are synthesized in shoot and root apices besides young leaf primordia.
- Auxins may be natural or synthetic.
- Naturally occurring auxins are indole-3- acetic acid (IAA) and its derivatives.
- NAA, 2, 4-D and 2,4, 5-T are synthetic auxins.
- Auxins in higher concentration promote the growth of stem.
- Auxins play an important role in initiation and promotion of cell division.
- Auxins help in the formation of adventitious roots from cuttings when applied in lower concentration.
- Auxins play an important role in apical dominance.
- Auxin prevents abscission by preventing the action of hydrolytic enzymes in abscission layer.
- Auxins are used to produce parthenocarpic fruits in plants like orange, apple, tomato and grapes.
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