How does crassulacean acid metabolism help succulent plants conserve water?

Crassulacean acid metabolism (CAM) helps succulent plants conserve water by temporally separating the stages of carbon fixation, allowing them to keep their stomata closed during the hot, dry daylight hours.12

In most plants, stomata remain open during the day to facilitate gas exchange, which leads to significant water loss through transpiration. In contrast, CAM plants open their stomata only at night when the air is cooler and more humid, significantly reducing water loss. During these nocturnal hours, the plants assimilate carbon dioxide and fix it into organic acids, such as malate, which are stored in the cell vacuoles.23145

During the day, the stomata remain closed to prevent evaporation. The stored malate is then released and decarboxylated, providing the carbon dioxide necessary for the Calvin-Benson cycle to complete photosynthesis using Rubisco. By restricting gas exchange to the night, these plants require considerably less water than other species to fix the same amount of carbon dioxide.15