Final answer:
C4 plants minimize photorespiration by fixing CO2 in mesophyll cells and then releasing it in bundle sheath cells for the Calvin cycle, while CAM plants store CO2 as malic acid at night and use it during the day when stomata are closed.
Step-by-step explanation:
C4 and CAM plants have developed special adaptations to minimize the effects of photorespiration, which can be detrimental to plant efficiency, especially under hot and dry conditions. C4 plants, such as corn, utilize a two-step carbon fixation process where the first step involves PEP carboxylase in the mesophyll cells, enabling the fixation of CO2 as four-carbon malic acid that is then transported to bundle sheath cells. Here, malic acid is decarboxylated to release CO2 for the Calvin cycle, achieving higher CO2 concentration and efficiency while allowing the stomata to be open for part of the day.
CAM plants, including cacti and succulents, fix CO2 at night when their stomata are open, limiting water loss. They store carbon in the form of malic acid within their vacuoles. During the day, with stomata closed to save water, the stored malic acid is converted back to CO2 for the Calvin cycle. This adaptation allows CAM plants to thrive in arid environments by conserving water and avoiding photorespiration.