Talk about the mechanism of CAM plants.

Crassulacean Acid Metabolism. They differ from C4 plants by the fact that carbon sequestration is not separated in space (mesophyll / bundle sheath), but over time (day / night). CO2 fixation on phosphoenolpyruvate (PEP) and the production of oxaloacetate take place at night when the stomata are open. The oxaloacetate is converted to malate which quickly is stored in the vacuole overnight as malic acid. During the day, when the stomata are closed, malic acid is included in the vacuole overnight as malic acid. During the day, when the stomata are closed, malic acid is included in the vacuole and the CO2 is transferred to RUBP of Calvin cycle. In Crassulaceae, the stomata close during the day, which reduces water loss through transpiration.