Final answer:
Desert plants close their stomata during the day to conserve water and reduce transpiration. Some, like cacti, also perform initial photosynthesis stages at night through temporal separation, helping them survive in arid conditions.
Step-by-step explanation:
Desert plants have developed various adaptations to conserve water and ensure they can continue to carry out photosynthesis under the arid conditions where they live. One key adaptation is the closing of stomata during the daytime. Stomata are small openings on the leaves through which plants take in carbon dioxide and release oxygen and water vapor. By closing these during the heat of the day, desert plants significantly reduce the loss of water via transpiration. Furthermore, some desert plants, like cacti, have evolved strategies such as performing the initial stages of photosynthesis at night when temperatures are cooler, which allows them to open their stomata and minimize water loss. This process is known as temporal separation of photosynthesis and is part of a suite of adaptations known as Crassulacean acid metabolism (CAM).