What are Stomata?
Stomata are the small (tiny ) openings that are present on the leaf epidermis. It is helpful to exchange gases Stomata are also found on stems and other parts of some plants.
Structure of Stomata
Each stoma is surrounded by two guard cells.
The guards are kidney-shaped and contain chloroplasts.
There is a respiratory chamber present in each stoma.
Fig – Showing Mechanism of opening and closing process of stomata
Mechanism of opening and closing process of stomata
The opening and closing of the stomata are caused by a variety of mechanisms.
The turgor pressure in the guard cells affects both opening and closing.
Guard cell swelling brought on by water absorption opens stomatal pores, whereas guard cell shrinkage closes the pores.
Stomata open and close as a result of guard cell turgor changes. The stomatal pore is open in turgid guard cells while the stomatal aperture closes in flaccid ones.
The stomatal pore’s opening and closing are explained by other theories.
The sugar in guard cells changes into starch in the absence of light. Since the starch is insoluble, the guard cells are kept at a lower concentration than the surrounding cells. The surrounding cells then osmotically remove the water from the guard cells, causing them to become flaccid and their stomata to close.