Question

Delaying aging of leaves and opening of stomata are due to the action of _______

• A. Auxins
• B. Gibberellins
• C. Cytokinins
• D. Abscisic acid

Answer 1

The correct option is C Cytokinins

A. Auxins are the plant hormones which promote cell enlargement and cell differentiation. It also promote fruit growth. It is responsible for phototropic and geotropic responses of plants.

B. Gibberellins are plant hormones which promote cell enlargement and cell differentiation in the presence of auxins. It help in breaking the dormancy in seeds and buds. It also promote fruit growth. It stimulates elongation of shoots of various plants.

C. Cytokinins are plant hormones which promote cell division in plants. It also helps in breaking the dormancy in seeds and buds. The delay the ageing of leaves. It promotes opening of stomata.

D. Abscisic acid (ABA) is a plant hormone which functions mainly as a growth inhibitor. It promotes the dormancy in seeds and buds [ this is the opposite of breaking the dormancy. It also promotes closing of stomata. It promotes falling of leaves.

So, the correct answer is 'Cytokinins'.