MCQ IN MEDICINE

Detailed explanation-1: -Natural openings on the leaf surface, such as stomata, provide an entry site to pathogens. Plants have evolved a mechanism to close stomata upon sensing microbe-associated molecular patterns (MAMPs). This mechanism is known as stomatal defense.

Detailed explanation-2: -Stomatal closure is a common adaptation response of plants to the onset of drought condition. Stomata are microscopic pores on the leaf epidermis, which regulate the transpiration/CO2 uptake by leaves.

Detailed explanation-3: -The opening and closing of stomata depend on the turgor pressure, caused by the osmotic flow of water in the guard cells. When the guard cells are turgid, they expand resulting in the opening of stomata. When the guard cells lose water, they become flaccid leading to stomatal closure.

Detailed explanation-4: -The opening and closing of stomata is known as stomatal movement. When guard cells are turgid, stomata open and when flaccid, stomata close. The outer wall (convex) of guard cell is thin and inner wall (concave) is thick.