Effects of NaCl stress on seed germination, leaf gas exchange and seedling growth of Pteroceltis tatarinowii

Effects of NaCI on seed germination, leaf gas exchange and seedling growth were investigated. The germination of P. tatarinowii seeds was delayed in the presence of NaCl, and was significantly inhibited when NaCl concentration exceeded 17 mM （1.0 g·L^-1）. NaCl treatments induced reductions of transpiration rate, stomatal conductance and net photosynthetic rate and their reductions were significant with the increasing of NaCl concentration. However, intercellular CO2 concentration in seedling leaves under salt stress was significantly higher than that of controls. There was a significant reduction in survival, basal diameter increment and height increment witl increasing NaCl concentration 50 days after NaCl treatment, and a significant reduction in the dry weight increment of roots, stems, and leaves was also observed in the NaCl treatments. The deleterious effect on the biomass increment was more evident in the case of stems and leaves. Results from this study suggest that P. tatarinowii is sensitive to salinity stress and the salinity threshold for seedling growth might be less 34 mM （2.0 g· L^-1）.