Question 49
Name various plant hormones. Also, give their physiological effects on plant growth and development.
Main plant hormones are :
(a) Auxin: Synthesized at shoot tip and helps in the growth of the plant. Auxin is also responsible for phototropism in plants that is more growth of cells towards the light.
(b) Gibberellin: Helps in the growth of the stem. It also has a role in other plant processes, such as stem elongation, germination, flowering, and fruit ripening.
(c) Cytokinins: Promotes cell division present in greater concentration in areas of rapid cell division, such as in fruits and seeds.
(d) Abscisic acid: Inhibits growth, causes wilting of leaves and also plays an important role in the inhibition of seed germination and budding. It is known as the plant stress hormone and is involved in the response of plants to weather stress, such as tolerance to cold and drought.