Thursday, October 17, 2019
What Role does Bundle Sheaths Play in C4 Plants Essay
What Role does Bundle Sheaths Play in C4 Plants - Essay Example Bundle sheath cells are the major site of refixation of the CO2 and C4 acid decarboxylation. The mesophyll cells also concentrate the CO2 and send it to the bundle sheath cells. NADP-malic enzyme (NADP-ME) and phosphoenolpyruvate carboxykinase (PCK) are expressed in the bundle sheath cells of the C4 plants. They are the major enzymes responsible for the refixation of the CO2 from the C4 acid. (Nomura et al. 2005). In C4 leaves, each vein is surrounded by a ring of the bundle sheath cells surrounded again by the mesophyll cells. These bundle sheaths have the chloroplasts arranged centrifugally with the large starch granules and unstacked thylakoid membranes. In the bundle sheath cells ribulose-1,5-bis-phosphate carboxylase/oxygenase (Rubisco) enzyme accumulates extensively. The specific enzyme activity can be easily determined by using the non aqueous fractionation techniques and pulse labeling techniques. (Majeran et al. 2005).