Question

Explain the structure of stomata.

Answer 1

Structure of stomata:

1. A stoma is a pore, found in the leaf and stem epidermis that is used for gas exchange.
2. The pore is bordered by a pair of specialised parenchyma cells known as guard cells which are responsible for regulating the size of the opening.
3. The inner wall of the guard cells is thicker than the outer wall.
4. The term stoma is also used collectively to refer to an entire stomatal complex, both the pore itself and its accompanying guard cells.
5. Subsidiary cells cells are located adjacent to the guard cell in the stoma of a leaf.
6. It functions by providing support in the movement of guard cells.
7. Stomatal pores are minute pores or the opening of the stomata.
8. These stomatal Pores play a significant role in gaseous exchange.
9. Air containing carbon dioxide and oxygen enters the plant through these openings where it is used in photosynthesis and respiration, respectively.
10. Oxygen produced by photosynthesis in the spongy layer cells (parenchyma cells with pectin) of the leaf interior exits through these same openings.
11. Also, water vapour is released into the atmosphere through these pores in a process called transpiration.

Diagram: