Stomata of CAM plants

The correct answer is option 'D' - CAM plants open their stomata during the night and close them during the day. To understand why this is the correct answer, let's first understand what CAM plants are and how they differ from other types of plants.

What are CAM Plants?
CAM stands for Crassulacean Acid Metabolism, which is a unique photosynthetic pathway found in certain plants. CAM plants are adapted to arid environments and exhibit a specialized form of photosynthesis that allows them to conserve water.

Stomata and their Function
Stomata are small openings found on the surface of plant leaves and stems. They play a vital role in the exchange of gases, such as carbon dioxide and oxygen, as well as the regulation of water loss through transpiration. Stomata are surrounded by two specialized cells known as guard cells, which control the opening and closing of the stomatal pore.

Explanation of the Correct Answer
CAM plants, unlike most other plants, have a different strategy for minimizing water loss and maximizing carbon dioxide uptake. They keep their stomata closed during the day to prevent excessive water loss through transpiration. This is especially important in arid environments where water availability is limited.

During the night, when the temperature is cooler and the relative humidity is higher, CAM plants open their stomata. This allows them to take in carbon dioxide needed for photosynthesis while minimizing water loss. The carbon dioxide is initially incorporated into organic acids and stored in vacuoles within the plant cells.

Advantages of Opening Stomata at Night
Opening stomata at night offers several advantages for CAM plants:

1. Reduced Water Loss: By opening stomata at night when the air is cooler and humidity is higher, CAM plants can minimize water loss through transpiration.

2. Efficient Carbon Dioxide Uptake: Opening stomata at night allows CAM plants to take in carbon dioxide when it is less likely to be lost through transpiration. This helps them maximize their carbon fixation efficiency.

3. Minimized Overheating: Opening stomata during the day in hot and arid environments can lead to excessive water loss and overheating of the plant. By keeping stomata closed during the day, CAM plants can avoid these issues.

4. Energy Conservation: The stored organic acids produced during the night are then used during the day for photosynthesis. This allows CAM plants to conserve energy and maintain their metabolic processes even when stomata are closed.

In conclusion, CAM plants open their stomata during the night and close them during the day to minimize water loss and maximize carbon dioxide uptake. This unique adaptation allows them to survive and thrive in arid environments.