Osmolytes Accumulation, Cell Membrane Integrity, and Antioxidant Enzymes in Sugarcane Varieties Differing in Salinity Tolerance

Osmolyte accumulation (proline and glycine–betaine), chlorophyll content, nitrate reductase (NR) activity and antioxidative system in terms of superoxide dismutase (SOD), ascorbate peroxidase (APX), catalase (CAT) and malondialdehyde content was studied in two sugarcane varieties (CoM-265 and CoC-671) differing in salt tolerance. The result clearly indicated higher level of osmolytes like proline and glycine–betaine in CoM-265, a salt tolerant variety. The reduction in chlorophyll content and NR activity was less in salt tolerant sugarcane variety CoM-265 than that of CoC-671, a salt susceptible variety. Higher activity of SOD, APX and CAT with lower LPO content in salt tolerant (CoM-265) variety compared to salt susceptible (CoC-671) variety, suggests that antioxidant enzymes protect cell from oxidative burst. Proline and glycine–betaine protect cell membrane integrity by maintaining higher chlorophyll and NR activity by scavenging ROS under salt stress.