Question

Explain how gaseous exchange occurs in plants through stomata and lenticels.

Hint:

{Stomata} help in gaseous exchange and transpiration in leaves, while {lenticels} allow gaseous exchange in woody stems.

Answer 1

Concept: Plants require gases such as carbon dioxide for photosynthesis and oxygen for respiration. The exchange of these gases occurs mainly through specialized structures called stomata and lenticels.
Step 1:Gaseous Exchange through Stomata Stomata are tiny pores present on the surface of leaves, mostly on the lower epidermis. Each stoma is surrounded by a pair of guard cells that control its opening and closing.

• During photosynthesis, carbon dioxide from the atmosphere enters the leaf through stomata.
• Oxygen produced during photosynthesis diffuses out through the stomata.
• Water vapor is also lost through stomata in a process called transpiration.

Step 2:Gaseous Exchange through Lenticels Lenticels are small pores found in the bark of woody stems. They allow the exchange of gases between the internal tissues of the plant and the atmosphere.

• Oxygen enters the stem through lenticels for respiration.
• Carbon dioxide produced during respiration diffuses out through lenticels.

Step 3:Diffusion Process The movement of gases in plants occurs mainly by the process of diffusion, where gases move from a region of higher concentration to a region of lower concentration.