What is the primary benefit of C4 photosynthesis over C3 photosynthesis?

The primary benefit of C4 photosynthesis over C3 photosynthesis lies in its increased carbon fixation at higher temperatures. C4 plants have specialized anatomy and biochemical pathways that allow them to efficiently capture carbon dioxide even in conditions that would otherwise inhibit the process in C3 plants.

Under high temperatures and intense sunlight, C3 photosynthesis can become less efficient due to a process called photorespiration, where oxygen competes with carbon dioxide for the active site of the enzyme RuBisCO. This competition reduces the overall efficiency of photosynthesis. C4 plants mitigate this issue by initially incorporating carbon dioxide into a four-carbon compound in mesophyll cells, which is then shuttled to specialized bundle sheath cells where the carbon is released for the Calvin cycle. This adaptation not only improves carbon fixation under high temperatures but also helps to minimize photorespiration, leading to a more effective overall photosynthetic process in warmer environments.

This adaptation is particularly beneficial in areas where temperatures are high and water availability can be limited, allowing C4 plants to thrive in environments such as tropical and subtropical regions.