AP BIOLOGY

Detailed explanation-1: -17.4. CAM plants uptake CO2 with nocturnal stomatal conductance followed by fixation of carbon into malic acid by PEP carboxylase and malate dehydrogenase. Substantial amount of malic acid is accumulated overnight. Stomata are closed next morning and malic acid is decarboxylated to release CO2.

Detailed explanation-2: -Pineapple (Ananas comosus (L.) Merr.) is the most economically valuable crop possessing crassulacean acid metabolism (CAM), a photosynthetic carbon assimilation pathway with high water-use efficiency, and the second most important tropical fruit.

Detailed explanation-3: -CAM Photosynthesis CAM pathway is adapted in plants to perform photosynthesis under stress. The CAM pathway reduces photorespiration. In CAM plants stomata are open at night and they absorb carbon dioxide at night to reduce water loss during the daytime.

Detailed explanation-4: -Their stomata remain open during the night. This is done because they tend to minimise the rate of transpiration. It is the characteristic feature of CAM plants. These plants fix carbon dioxide during the night but form sugars only during the day when RuBisCO is active.