Question

Which of the following statements is correct about CAM plants?

• A. The stomata remains open throughout day and night
• B. The stomata remains open during the day and close during the night
• C. The stomata remains closed during the day and open during the night
• D. The stomata remains closed throughout day and night

Answer 1

The correct option is C The stomata remains closed during the day and open during the night

In CAM plants, the stomata remain closed during the day and open during the night. This happens so as to reduce loss of water due to transpiration. This process happens in plants occurring in desert regions. During the night, phosphoenolpyruvate accepts $C{O}_2$ to form oxaloacetic acid, which is then converted to malic acid. This malic acid is stored in the vacuole. During the day, the stomata remains closed; so $C{O}_2$ will not be able to enter into the leaf. So, vacuolar malic acid is converted to malate which is further broken down into $C{O}_2$ and pyruvate. This $C{O}_2$ is then used in photosynthesis.