Adaptive Responses of Birch-Leaved Pear (Pyrus betulaefolia) Seedlings to Salinity Stress

摘要: One-year-old birch-leaved pear (Pyrus betulaefolia Bunge) seedlings were subjected to 0, 50, 100, 150, and 200 mmol/L NaCl solutions for 27 days in order study the effects of salinity stress on photosynthesis, ion accumulation enzymatic non-enzymatic scavenging reactive oxygen species seedlings. The research was performed a greenhouse using potted trees. Salinity reduced photosynthetic rates, stomatal conductance water use efficiency leaves seedlings, but increased transpiration rates leaf temperature. Hydrogen peroxide superoxide anion radical contents with increasing concentrations, phenomena also observed malondialdehyde, suggesting that suffered from oxidative injury. Superoxide dismutase (SOD) catalase (CAT) activities quickly responded by when stress. Total protein content restrained stress, whereas ascorbate increased. glutathione once exposed low level (50 or 100 mmol/L) NaCl, high (150 NaCl) stimulated glutathione. Na+, Cl-, K+ Mg2+ Ca2+ levels ratio other ions Na+ except K+/Na+ under 50 conditions. This suggests possess capacity salt exclusion only conditions, does not play fundamental role as secondary messenger