Question

C4 plants, by decreasing photorespiration and efficiently carrying out photosynthesis, can?

• A. Decrease stomatal openings and thereby reduce water loss.
• B. Decrease stomatal openings and thereby reduce leaf temperature.
• C. Increase stomatal openings and thereby increase water loss.
• D. Increase stomatal openings and thereby increase leaf temperature.

Answer 1

The correct option is A

Decrease stomatal openings and thereby reduce water loss.

C4 plants convert carbon dioxide into malate in the mesophyll cells located on the outer part of the leaf using PEP carboylase. This malate is then transported to the bundle sheath cells where it is converted into pyruvate and carbon dioxide for Rubisco.
Since carbon dioxide is absorbed directly from the leaf surface, stomatal opening can be decreased to reduce water loss through photorespiration.