Abstract: Ammopiptanthus mongolicus, an endangered evergreen leguminous shrub, which is endemic to the semi-arid desert region of central Asia was successfully introduced in Tianjin by our team. In order to understand the mitigative effect of IBA and CaCl₂ of A.mongolicus seedlings under salt stress, the seedlings were treated with 1.3% NaCl and different concentrations of IBA and CaCl₂ under water culture. Antioxidant enzyme activities, photochemical efficiency of PSII and other related physiological index are measured and analyzed. The results showed that several treatments improved the growth of A.mongolicus seedlings; they were also helpful to increase the content of chlorophyll, the activity of antioxidant enzyme. It was also found that the application of IBA and CaCl₂ could decrease the accumulation of malondialdehyde (MDA). Therefore, the injuries induced by the salt stress were mitigated and salt resistance of A.mongolicus was raised by the low concentration of IBA and CaCl₂. When the concentration of IBA and CaCl₂ reached 5 and 20 mmol·L^-1, respectively, the seedlings growth were inhibited. The application effect of CaCl₂ is better than IBA.

Key words: salt stress, Ammopiptanthus mongolicus, IBA, CaCl₂