To survive in a dry environment with little and irregular rainfall, succulent plant may store water in any of their body parts, i.e. leaves, stems and roots. This system is only effective with sufficient isolation and with a large storage capacity.
These plants often show specific adaptations in their metabolism (CAM metabolism).
The various adaptations are connected and mutually reinforce their adaptive value.
To prevent water loss, the stomata of these plants are closed by day, to open only at night when temperature decreases and humidity rises. Since the absorption of
CO2 is only possible at night, CO2 storage and changes in metabolism are necessary to carry out photosynthesis by day.
At night CO2 is stored as malate in the large vacuoles, to be released for photosynthesis by day.
This mechanism was discovered first in Crassulacean plants, such as Crassula and therefore is called Crassulacean Acid (acid: malate) or CAM Metabolisme.
This type of metabolism appeared to occur not only dicot plants, but also in a number of monocots, among others the crop pineapple and the pot plant Sanseveria.
