ANTIOXIDANT ENZYMES RESPONSES OF DIFFERENT GENOTYPES OF LEYMUS CHINENSIS TO SALINE-ALKALI STRESS AND COMPREHENSIVE EVALUATION OF SALINE-ALKALI TOLERANCE

We conducted pot experiment with four genotypes of Leymus chinensis at different concentrations of saline-alkali treatment. The saline-alkali tolerance of different genotypes of L. chinensis were evaluated comprehensively by PCA, NIF and comprehensive evaluation value (D value). The results indicated that with the increase of intensity of saline- alkali stress, the content of soluble protein and the activities of CAT, POD, APX, GR, DHAR and MDHAR in the leaves of four genotypes of L. chinensis, ZS, MZ, DQ and CM, were increased compared with the control. And the activities of APX, DHAR and the content of soluble protein of ZS were significantly higher than those of other three genotypes. PCA was used to convert 8 single indexes into 3 comprehensive indexes under saline-alkali stress, and the cumulative contribution rate reached 100%. The D value of saline-alkali tolerance of four genotypes of L. chinensis were 0.167, 0.160, 0.158 and 0.149 respectively. Therefore, the four genotypes of L. chinensis have a certain degree of tolerance to saline-alkali stress, and their comprehensive saline-alkali tolerance of four genotypes were ZS > MZ > DQ > CM. This finding provides a certain method and material basis for further study on breeding of new varieties and antioxidant enzyme system of saline-alkali stress of L. chinensis.