Question

Case: Transpiration is the evaporative loss of water by plants. It occurs mainly through the stomata in the leaves. Besides the loss of water vapour in transpiration, exchange of oxygen and carbon dioxide in the leaf also occurs through pores called stomata. Normally stomata remain open during the day and close at night.

Based on the above case answer the following question:

Which of the following statements is not true for stomatal apparatus?

• A. Guard cells regulate the closing and opening of the stomatal pore.
• B. Guard cells enclose the stomatal pores.
• C. Stomata are involved in gaseous exchange.
• D. The guard cells shrink to open the stomatal pore.

Answer 1

The correct option is D The guard cells shrink to open the stomatal pore.

The opening and closing of the stomatal pores are regulated by the guard cells. The guard cells swell when water flows into them making the stomatal pore open. This leads to the exchange of gases via the stomata.