Question

Guard cells are kidney-shaped
A) Rice
B) Beans
C) Grasses
D) Maize

Answer 1

Hint: Guard cells are the living cells that guard the opening and closing of the stomatal pore. These cells are generally of kidney-shaped and dumb-bell shaped.

Complete Answer:
Let us find the correct answer from the following,
Option A: Rice is a monocot as it has only one cotyledon. Hence, it has dumb-bell shaped guard cells. Therefore, it is an incorrect answer.

Option B: Beans is a dicotyledon. Hence, it has kidney-shaped guard cells. Therefore, this is the correct answer.

Option C: Grasses are monocot. Hence, it has dumb-bell shaped guard cells. Therefore, this is an incorrect answer.

Option D: Maize is a monocot having only one cotyledon. Hence, it has dumb-bell shaped guard cells. Therefore, this is an incorrect answer.

Thus, the correct option is B) Beans.

Additional information: Stomata are the minute structure present in the epidermis of leaves. They are absent in the epidermis of roots. Each stoma is composed of a pair of guard cells and a tiny stomatal pore
- The wall of the guard cells towards the stomatal pore is called inner walls and away from the stomatal pore are called outer walls.
- The outer walls of the guard cells are thin while the inner walls are highly thickened. The thickening is limited to the middle part in the dumb-bell shaped guard cells.

Note: Guards cells control the opening and closing of the stomatal pore. When they are turgid (swollen), the stomatal pore is open and when they are flaccid (shrunken), the stomatal pore is closed.