Plants using the C4 photosynthetic pathway use rubisco to catalyze the reaction between O2 and RuBP. divide photosynthesis between mesophyll and bundle sheath cells are mostly trees have a lower rate of photosynthesis than plants using the C3 photosynthetic pathway use rubisco to catalyze the reaction between O2 and RuBP. divide photosynthesis between mesophyll and bundle sheath cells are mostly trees have a lower rate of photosynthesis than plants using the C3 photosynthetic pathway.