Question

How does exchange of gases takes place across the surface of the stem of a plant?

Answer 1

The exchange of gasses in the roots of a plant takes place by the process of diffusion. During diffusion, oxygen diffuses into the root hairs and passes into the root cells, from where the carbon dioxide moves out into the soil.

The exchange of gasses in stems: In woody plants gaseous exchange occurs through the small pores in the stems called lenticels.

The exchange of gasses in leaves: In leaves respiration takes place by diffusion of oxygen through stomata into the cells of the leaf from where the carbon dioxide is released into the atmosphere