Effects of exogenous betaine on seed germination and antioxidase activities of Lycium ruthenium seedlings under NaCl stress

In order to investigate the effects of exogenous betaine on seed germination, activities of antioxidase enzymes of Lycium ruthenium under NaCl stress. The L. ruthenium seed germination and seedling growth were studied in middle reaches of Heihe River of Hexi Corridor. Several physiological indexes, such as the germination percentage (GP), germination vigor (GV), germination index (GI), vigor index (VI), and relative salt damage rate, antioxidant enzymes (SOD, POD and CAT) were measured. The results indicated that, low NaCl concentration (25 mmol·L-1) could promote the seed germination but high NaCl concentration (50~300 mmol·L-1) could inhibit the seed germination. The NaCl concentration threshold for seed germination in L. ruthenium was 50 mmol·L-1, the maximum was 300 mmol·L-1; The SOD, POD and CAT activity showed a trend of first rising and then falling along with the salt concentration increasing. After the treatment by exogenous betaine, SOD, POD and CAT activity increased to some extent, but they had less decrease range under NaCl stress. Exogenous betaine could significantly alleviate the damages to the seeds and seedlings of L. ruthenium under NaCl stress and promote the salt resistance of the seeds and seedlings.