Question

Choose the correct answer from the alternatives given.
When stomata in a leaf close, then

• A. carbon dioxide in the air spaces in the leaf decreases
• B. oxygen in the air spaces in the leaf increases
• C. $C_3$ plants carry on photorespiration, using $O_2$ and producing PGA and $C{O}_2$
• D. all of the above

Answer 1

The correct option is D all of the above

When the stomata of the leaf are closed then the process i.e photosynthesis is replaced by the process called photorespiration in which they take up oxygen and give out the carbon dioxide. So the carbon dioxide level in the air space of leaf decreases and oxygen level increases. When Calvin cycle occur in the chloroplast of the leaf then it uses oxygen to work as a substrate for RuBisCo which uses ATP and NADPH and results in the formation of PGA molecule and Carbon dioxide is released out in the environment.

So the correct option is 'all of the above'.