Effect of Salt Stress on Antioxidant Enzymes, Soluble Sugar and Yield of Oat

The objective of this study was to evaluate the changing mechanism of soluble sugar, antioxidantenzymes of oat at reproductive stage under salt stress. Two cultivars selected (salt-tolerant Baiyan 2, salt-sensitive. Caoyou 1) were exposed to varied salt concentrations (0, 50, 100, 150, 200 mmol/L, respectively) at seedling stage. The salt was composed by NaCl, Na2SO4 (1:1). Our results were that (1) salt could decrease the yield and grain weight of oat, the adverse effect of salt on tolerant cultivar was less than that of sensitive cultivar. (2) In salt stress, the soluble sugar contents were reduced at heading stage and were increased at the grain filling stage. Larger increase percentage was observed in salt tolerant cultivar Baiyan 2 than in the salt sensitive cultivar Caoyou 1 compared to control. A positive correlation was detected between the soluble sugar and MDA contents at grain filling stage. (3) Salt stress improved the MDA contents at both stages and the MDA contents were higher in grain filling stage than in heading stage. Compared with the salt sensitive cultivar, the salt tolerant cultivar had the lower MDA contents. A negative correlation was found between MDA and yield. The salt increased the SOD, POD activity and decreased the CAT activity at heading stage. The increment of SOD, CAT activity and the reduction of POD activity were found at the grain filling stage. The result suggested that oat included the salt tolerance and the soluble sugar, antioxidant enzymes could be used for discriminating oats for their potential to tolerate salt.