Question

When strips of chloride papers are placed on either side of a dorsiventral leaf, why the strip on the lower side become speedily pink?

• A. More $C{O}_2$ is evolved from the lower side.
• B. More $O_2$ is evolved from the lower side.
• C. More $H_{2}O$ is lost from the lower side.
• D. All of the above.

Answer 1

Answer: (C)

More $H_{2}O$ is lost from the lower side.

This is a simple experiment to prove transpiration occurs through leaf surface. And it is also used to compare the rate of transpiration from the upper and lower side of the leaf. Chloride strip on the lower side of the leaf changes colour (blue to pink) fast, because of the presence of more stomata on lower surface as compared to the upper surface. This proves that the rate of transpiration is more on the lower side of the leaf.