Answer and Explanation:
Stomata are small openings found on the surface of leaves and stems of plants. They play a crucial role in gas exchange, allowing the plant to take in carbon dioxide (CO2) and release oxygen (O2) during photosynthesis. Stomata open in light and in the presence of a low concentration of carbon dioxide for the following reasons:
1. Light: Stomata open in response to light because they are involved in the process of photosynthesis. During photosynthesis, plants use light energy to convert carbon dioxide and water into glucose and oxygen. To carry out this process efficiently, plants need an adequate supply of carbon dioxide, which is obtained through the stomata. When light is available, the plant cells produce energy in the form of ATP, which is used to actively transport potassium ions into the guard cells surrounding the stomata. This influx of potassium ions leads to an increase in osmotic potential within the guard cells, causing water to move into them by osmosis. As a result, the guard cells swell and bend, causing the stomata to open.
2. Low concentration of carbon dioxide: Stomata also open in the presence of a low concentration of carbon dioxide. When the concentration of carbon dioxide inside the leaf decreases due to its consumption during photosynthesis, the plant responds by opening the stomata to allow more carbon dioxide to enter. This ensures a continuous supply of carbon dioxide for the photosynthetic process and helps maintain optimal rates of photosynthesis.
Overall, the opening of stomata in light and in the presence of a low concentration of carbon dioxide allows plants to efficiently carry out photosynthesis by facilitating the uptake of carbon dioxide and the release of oxygen. It helps maintain a balance between gas exchange and the needs of the plant for energy production and growth.