How do desert plants perform photosynthesis with closed stomata?

Desert plants have adapted to survive in arid environments by keeping their stomata closed during the day to reduce water loss through transpiration. However, this poses a challenge for photosynthesis, the process by which plants convert sunlight into energy. Despite closed stomata, desert plants have developed several mechanisms to carry out photosynthesis efficiently.

Crassulacean Acid Metabolism (CAM)
- Desert plants, such as cacti and succulents, utilize CAM photosynthesis, a unique pathway that allows them to open their stomata at night when temperatures are cooler and humidity is higher.
- During the night, these plants take in carbon dioxide and store it in the form of organic acids in their vacuoles.
- During the day, when stomata are closed, the stored carbon dioxide is released and used for photosynthesis, minimizing water loss.

Reduced Photorespiration
- By keeping their stomata closed during the day, desert plants also reduce the chances of photorespiration, a process that can occur when oxygen levels are high relative to carbon dioxide levels.
- Photorespiration can be energetically costly for plants, so minimizing this process allows desert plants to use their resources more efficiently for photosynthesis.

Efficient Water Use
- Desert plants have evolved to be highly efficient in their water use, maximizing the amount of carbon dioxide they take in through their stomata when they are open.
- By optimizing their water use, desert plants can carry out photosynthesis effectively even with closed stomata during the day.

In conclusion, desert plants have adapted to their harsh environments by employing strategies such as CAM photosynthesis, reducing photorespiration, and maximizing water use efficiency to perform photosynthesis efficiently despite having closed stomata during the day.