Effects of NaCl stress on ascorbateglutathione cycle in vegetable soybean seeds

The peroxide(H2O2)content and ascorbate(AsA)glutathione(GSH)cycle in seeds of two vegetable soybean cultivars［Glycine max (L.)Merr.］with different salt tolerances were studied using the vermiculite culture under 100 mmol/L NaCl stress. The results show that H2O2 contents in seeds of two vegetable soybean cultivars are significantly increased under the NaCl stress, and the increased amount of Llingtezao resistant to the NaCl stress is lower than that of Lixianggaochan 95-1susceptible to the NaCl stress. During the NaCl stress period, the activities of ascorbate peroxidase(APX), dehydroascorbate reductase(DHAR)and glutathione reductase(GR), contents of AsA and GSH, and ratios of AsA/DHA and GSH/GSSG of Llingtezaoare higher than those of Lixianggaochan 95-1, and/or their decrease were lower than those of Lixianggaochan 95-1. While contents of dehydroascorbic acid(DHA)and oxidized glutathione(GSSG)of Llingtezaoare lower than those of Lixianggaochan 95-1. These results indicate that Llingtezaocould maintain efficient metabolism of AsAGSH cycle during the stress period, and further maintain lower H2O2 accumilation. This might be one of important reasons for higher salt tolerance of Llingtezao.