How do stomata regulate gas exchange in plants?

Stomata regulate gas exchange in plants by opening and closing to allow or restrict the flow of gases.

Stomata are tiny openings or pores, primarily found on the underside of plant leaves. They play a crucial role in photosynthesis, a process where plants convert light energy, usually from the sun, into chemical energy in the form of glucose. For this process to occur, plants need to take in carbon dioxide from the atmosphere and release oxygen, which is facilitated by the stomata.

The opening and closing of stomata are regulated by guard cells that surround each stoma. When these guard cells are filled with water, they swell, causing the stoma to open. This allows carbon dioxide to enter the leaf and oxygen and water vapour to exit. Conversely, when the guard cells lose water, they shrink, causing the stoma to close. This prevents the loss of water from the plant, a process known as transpiration.

The regulation of stomata opening and closing is influenced by various factors including light, carbon dioxide concentration, temperature, and humidity. For instance, in the presence of light, photosynthesis can occur, so stomata typically open to allow the intake of carbon dioxide. On the other hand, in conditions of high temperature or low humidity, stomata often close to prevent excessive water loss.

In summary, stomata serve as gatekeepers for gas exchange in plants. By opening and closing in response to environmental conditions, they balance the need for carbon dioxide intake for photosynthesis with the need to minimise water loss through transpiration.