Why does not photorespiration take place in C4 plants?
Photorespiration is associated with C3 cycle, where plant lose CO2 fixation because of the increase in concentrate ion of O2 and change the nature of activity of RuBP carboxylase oxygenase.
C4 plants have evolved a mechanism to avoid loss of CO2. There is not a direct contact of RuBP carboxylase-oxygenase as C3 cycle operates in bundle sheath cells (where both temperature and oxygen level low).
CO2 fixation is done by another enzyme PEP carboxylase in mesophyll cells and oxaloacetate is formed which is converted to malic acid and transported to bundle sheath cells.
There, it gives off CO2 which is used in Calvin cycle, operating in bundle sheath cells of C4 plants.
