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