Question

Explain how does the exchange of gases occur in plants across the surface of roots, stem and leaves.

Answer 1

Hi friend !!!
the exchange of gases in roots of a plant takes place by the process of diffusion. the exchange of gases is mostly done with the help of stomata.Plant breath in through stomata present in their bodies.  
Hope this helps:D

Answer 2

Just like animals, plants respire to survive as well. Different parts of a plant have different systems or organs to respire gases.

In leaves there is special mouth like openings called stomata which performs the exchange of gases.

In stems of woody plants, there some pores which perform the exchange of gases .These pores are called Lenticels.

In roots, there are small pores present on the surface of root hair which exchange gases via diffusion.