Abstract: The Ammopiptanthus mongolicus seedlings were treated with different NaCl concentrations under water culture. Morphological indices and physiological indices were measured and analyzed. The result indicated that：Along with the increase of salt concentrations, the chlorophyll contents and the fluorescent parameters (F_v/F_o and F_v/F_m) decreased, the MDA contents increased. The activity of superoxide dismutase (SOD) and peroxidase (POD) first rose and then decreased as the salt concentration increased; the seedlings under 0.7% NaCl stress had the highest POD activity, the POD activity gradually decreased when the concentration rose to 1.0% and 1.3%. The contents of proline increased evidently with the increasing of NaCl concentrations, but the soluble sugar only increased in roots. With the NaCl stress degree intensifying, the death rate also increased, and reached 53.33% and 76.67%. It was thus suggested that the seedlings treated with 0.4%~0.7% NaCl showed strong resistance; when treated with 1.0%~1.3% NaCl, the seedlings were badly influenced.

Key words: NaCl stress, Ammopiptanthus mongolicus, seedlings, physiological characteristic