Question

An adaptation for better gaseous exchange in plant leaves is

(a) hair on lower surface

(b) multiple epidermis

(c) waxy cuticle

(d) stomata on lower surface away from direct sun rays.

Answer 1

Answer-d) stomata on lower surface away from the direct sun rays.

The stomata present on the surface of the leaves have guard cells which open and close in response to light in the presence of water and gases. The pores of the guard cells open to allow the entry and exit of gases from the surface of the leaf. The guard cells have chloroplasts inside the plastids which help the plant during photosynthesis. When conditions are dry, the stomata close and prevent the entry of gases and the loss of water and other metabolites from the surface of the leaf. The other cells present in the stomata are the subsidiary cells.Hence, option (d) is correct.

hair on lower surface- It helps in reflecting light and protecting the surface of the leaf against harsh weather conditions of humidity, dryness ,pressure and temperature changes. hence, option (a) is incorrect.

waxy cuticle-- It is a protection layer made of lipids and hydrocarbon polymers and protects the loss of the water from the epidermal cells in the leaf.hence, option (c) is incorrect.

multiple epidermis-- The multiple layers of the epidermal cells provide a barrier against the loss, movement and the transport of water and mineral ions across the leaf. Hence, option (b) is incorrect.