Effects of NaCl Stress on AsA-GSH Cycle in Seedlings of Hibiscus hamabo

In November 2013, seeds of Hibiscus hamabo were harvested in Zhoushan, Zhejiang province, and in next June and July, sand cultured for experiment on response of ascorbate-glutathione (AsA-GSH) cycle of early stage seedlings under different concentrations of NaCl stress. The results showed that the activity of superoxide dismutase (SOD), ascorbic acid peroxidase (APX) and glutathione reductase (GR) of seedlings treated by 150 and 300 mmol·L-1NaCl was significantly higher than that of the control (no treatment), and of seedlings with cotyledons increased at first and then decreased. The content of AsA and GSH had negative relation with the concentration of NaCl, while O2 ·- production rate and H2O2 content had positive one. However, in the early stage seedlings, as high salinity buoyed up the O2 ·- production rate and H2O2 level, the activity of SOD, APX and GR and the content of AsA and GSH were increased with the concentration of NaCl.