Question

Bulliform or motor cells occur in

• A. Upper epidermis of dicot leaves
• B. Upper epidermis of monocot leaves
• C. Lower epidermis of monocot leaves
• D. Lower epidermis of dicot leaves

Answer 1

The correct option is B Upper epidermis of monocot leaves

Bulliform cells or motor cells are large, bubble shaped epidermal cells that occur in groups on the upper surface of the leaves of many grasses. Loss of turgor pressure in these cells causes leaves to roll up during water stress. During drought, the loss of moisture through vacuoles induces bulliform cells to cause the leaves of many grass species to close as the two edges of the grass blade fold up toward each other. Once, adequate water is available, these cells enlarge and the leaves open again. Bulliform cells are absent in dicot leaves.
Thus, the correct answer is option B.