Question

Motor cells help in

• A. Inward rolling of leaves
• B. Transpiration
• C. Guttation
• D. All of the above

Answer 1

The correct option is A Inward rolling of 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 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. Folded leaves offer less exposure to sunlight, so they are heated less thus, reducing evaporation and conserving the remaining water in the plant. They are thought to play a role in the unfolding of developing leaves and in the rolling and unrolling of mature leaves in response to alternating wet and dry periods. So, motor cells helps in inward rolling of leaves and not in transpiration or guttation.
Thus, the correct answer is option A.