CBSE Class 10 Answered

Desert plants are CAM plants i.e. they perform Crassulacean acid metabolism. This metabolism was first observed in Crassulacean plants.

At night, the stomata are open and take in carbon dioxide. PEP carboxylase fixes carbon dioxide and produces a four carbon molecule malate. The malate gets stored in the vacuoles of the mesophyll cells.

During day, the stored malate is pumped out of the vacuoles into the stroma of the chloroplasts and broken down into carbon dioxide and enters the Calvin cycle to produce glucose.