Response to NaCl stress in salix matsudana koidz seedlings

The effects of different NaCl concentrations (0.1, 0.2, and 0.4%) on plant growth, the enzymatic antioxidant system, lipid peroxidation, and cell damage were investigated in Salix matsudana Koidz to better understand the tolerant mechanism under NaCl stress. The results indicate that cell damage was induced in roots by NaCl stress as early as after just 1 h of exposure, which increased with increasing NaCl concentration and prolonged treatment. The activities of SOD, POD, and CAT in S. matsudana under NaCl stress were enhanced except for the SOD activity in leaves under 0.4% NaCl at day 28, and CAT activities in leaves exposed to 0.4% NaCl on days 21 and 28. NaCl exposure caused increasing O₂⁻ and H₂O₂ contents. The MDA content in roots exposed to 0.2 and 0.4% NaCl increased except for that in 0.2% NaCl on day 14 compared with control. The MDA level in leaves of control was lower than that of all NaCl treatments. The soluble protein contents in roots increased significantly (P<0.05), except for that 0.1% NaCl during days 21 to 28. It increased significantly in leaves exposed to 0.4% NaCl, but decreased sharply at day 28.