We all know that stomata are the tiny pores on the leaves which play a major role in the exchange of gases. The intake of carbon dioxide and the outgoing of oxygen both takes place through these pores. The respiration in leaves takes place through the tiny pores called stomata present on them. The exchange of gases occurs through these pores. The oxygen is transported to other cells of the plant by diffusion and in the same carbon dioxide is removed from the cells. In this way respiration takes place in leaves.
Guard Cells in Stomata
The cells in the leaf of a plant that control the opening and closing of stomata are guard cells. These cells are in bean shape and surround the stoma. These are the epidermal cells and help in exchange of gases by opening and closing of stomata. These also play a major role in transpiration and minimal loss of water. Light is a major aspect of these guard cells. The guard cells regulate the opening and closing of stomatal pores by the osmosis process. When water flows into the guard cells, they swell up and the curved surface causes the stomata to open. When the guard cells lose water, they shrink and become flaccid and straight thus closing the stomata.
Functions of the stomata
- They allow the exchange of gases (CO2 and O2) with the atmosphere.
- Evaporation of water from the leaf surface occurs through the stomata. Thus, the stomata help in the process of transpiration.
- Based on the climatic conditions, it closes or opens its pores to maintain the moisture balance.
- Allows the intake of carbon dioxide and to give out oxygen during the process of photosynthesis.
- Stomata remain open during the day and closed at night. This closure at night prevents water from escaping through open pores.