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:

Water vapour comes out from the plant leaf through the stomatal opening. Through the same stomatal opening, carbon dioxide diffuses into the plant during photosynthesis. Reason out the above statements using one of the following options.

• A. The above processes happen only during night time.
• B. One process occurs during the day time and the other during night.
• C. Both processes cannot happen at the same time.
• D. Both processes can happen together at daytime.

Answer 1

The correct option is D Both processes can happen together at daytime.

The loss of water in the process of transpiration and the exchange of gases during photosynthesis take place through the stomatal pores. The rate of transpiration is higher in day in comparison to night. Photosynthesis on the contrary takes place during the day only. Hence, both transpiration and photosynthesis can happen at daytime.