Name various plant hormones. Also give their physiological effects on plant growth and development.

Explanation

The various plant hormones are:
Auxin, Gibberellin, Cytokinin, Abscisic acid.
Auxin: It helps in growth of the tissues. When growing plants detect light, a hormone called auxin, synthesised at the shoot tip, helps the cells to grow longer. When light is coming from one side of the plant, auxin diffuses towards the shady side of the shoot. This concentration of auxin stimulates the cells to grow longer on the side of the shoot which is away from light.
Thus, the plant appears to bend towards light.
Gibberellin: Helps in the growth of the stem.
Cytokinin: Promote cell division, they are present in greater concentration in areas of rapid cell division, such as in fruits and seeds.
Abscisic acid: Inhibits growth. Wilting of leaves is due to abscisic acids.