Question

(b) Describe the exchange of gases which takes place in the leaves of a plant (a) during daytime, and (b) at night.

Answer 1

Answer:
Exchange of gases in the leaves of a plant during daytime:
During the daytime, when photosynthesis occurs, oxygen is produced. The leaves use some of this oxygen for respiration and the rest of the oxygen diffuses out into the air. Again, during the daytime, carbon dioxide produced by respiration is all used up in photosynthesis by leaves. Even more carbon dioxide is taken in from the air. Thus, the net gas exchange in leaves during daytime is: $O_2$ diffuses out; $C{O}_2$ diffuses in.

Exchange of gases in the leaves of a plant at night:
At night time, when no photosynthesis occurs and hence no oxygen is produced, oxygen from the air diffuses into leaves to carry out respiration. And carbon dioxide produced by respiration diffuses out into the air.