EFFECTS OF SALINITY ON ANTIOXIDANT ENZYMES AND PROLINE IN LEAVES OF BARLEY SEEDLINGS IN DIFFERENT GROWTH STAGES

摘要

The participation of antioxidant defence under mild and severe salt stress conditions (120 and 240 mM) on barley (Hor-deum vulgare L.) seedlings in different growth stages, antioxidant enzyme (superoxide dismutase, peroxidase and catalase) activitiesand proline content were determined. Plants grown in Hoagland solution served as control. Salinity induced proline accumulation in both 2- and 4-week-old-seedlings (up to 8.7-fold and 1.8 fold, respectively, as compared with control). The activities of antioxidant enzymes in leaves increased under NaCl stress, the seedlings in the early growing stage (2-week-old) being generally more responsive than 4-week-old ones. The highest peroxidase (POX) and superoxide dismutase (SOD) activities were 165 and 152% of control, respectively. Catalase (CAT) activity reached about 7- fold increase in NaCl treatment of 2-week-old seedlings. This dramatic increase might indicate that CAT is a major enzyme among antioxidant enzymes examined in barley under salt stress.Thus, antioxidant defence system induced by salinity plays prominent role particularly in early growth periods and its efficiency decrease with age of the plants.