Question

when do the desert plant take up carbon dioxide and perform photosynthesis

Answer 1

Desert plant takes up carbon dioxide by their pores of stomata which is open at night at day the pores of stomata is closed to prevent the loss of water and the process of photosynthesis occurs at day in the presence of sunlight , carbon dioxide , water and chlorophyll .
I hope your doubts are clear

Answer 2

Desert plants take up Carbon dioxide at night and prepare an intermediate which is acted upon by the energy absorbed by the chlorophyll during the day.