CBSE Class 10 Answered

Different plant hormones help to coordinate growth, development and responses to the environment. They are synthesised at places away from where they act and simply diffuse to the area of action.The important plant hormones are auxins, cytokinins, gibberellins, abscisic acid and ethylene.

Auxins promote stem elongation (by promoting cell elongation) and inhibit growth of lateral buds (maintains apical dominance).

Cytokinins promote cell division.

Gibberellins stimulate cell division and elongation in plants.

Abscisic acid inhibits growth. It promotes seed dormancy by inhibiting cell growth. Its effects include wilting of leaves.

Ethylene is a gaseous plant hormone that stimulates fruit ripening and the dropping of leaves.