Question

Tiny pores present on the leaves of plants are called as
A) Stomata
B) Cells
C) Chlorophyll
D) Grains

Answer 1

Hint: A leaf is a principal lateral appendage of a vascular plant system. It is specialized for photosynthesis. Leaves are mostly green in color as it contains chlorophyll which is essential for photosynthesis.

Complete answer:
>The stomata are the tiny pores present on the surface of leaves of plants.
>They help in exchange of gases.
>Each stoma has guard cells.
> Their opening and closing are due to change in the turgidity of guard cells.
>The guard cells are responsible to regulate the rate of transpiration by opening and closing the stomata.
> Stomatal pore may be defined as the guard cells occurring in pairs with gap between them.
>The guard cells have thick cuticles on the pore side and thin opposite to it.
>The opening of the stomata leads to increase in the turgidity of guard cells. The shape of outer walls become bulge while the inner walls become crescent shaped.
> The guard cells lose their turgidity when stomata close. The outer and inner walls get their original shapes. Cell walls of varying thickness and different orientation of cellulose microfibers are present in the guard cells which are responsible for their bending outward when they are turgid and thus stomata open.

Hence the correct answer is option ‘A’ Stomata.

Note:Turgor pressure of two guard cells regulates the opening and closing of stomatal pore. The movements of large numbers of ions and sugars into and out of guard cells regulates the turgor pressure.