Abstract: Lycium barbarum has strong ability to salt and alkali resistance, and its cultivation in salinized soil can improve soil quality to a certain extent. However, less information was found about physiological adaptation to different saline habitats under different salinization level in L. barbarum. In order to analyze the physiological response difference of L. barbarum to single salt (NaCl or Na₂SO₄) and mixed salt (NaCl+Na₂SO₄), we selected one year seedling of Ningqi No.5 as the materials to treatment under different saline solution with different osmotic potential gradients (-0.48, -0.82 and -1.18 MPa, respectively). The results showed that chlorophyll (Chl) content decreased, but the content of malondialdehyde (MDA), proline (Pro) and soluble sugar (SS), and activities of anti-oxidant enzyme superoxide dismutase (SOD) and catalase (CAT) increased with the decreasing of osmotic potential under different salt treatment. Peroxidase (POD) activity was inhibited at osmotic potential of -1.18 MPa. Among different salt solution with the same osmotic potential, the contents of Chl, Pro, MDA and SS and activities of SOD and CAT more or less increased under mixed salt treatment. MDA, Pro and SS contents and CAT activity increased during treatment. All these results suggested that the protective capability enhanced from osmo-regulated substances and anti-oxidant enzyme system of L. barbarum at high salinization level. The physiological responses of L. barbarum were different in different saline environments, and the effect of mixed salt stress was greater than that of single salt at -1.18 MPa. The accumulation of osmo-regulated substances and ability to saline adaptation of L. barbarum increased during salt treatment.

Key words: Lycium barbarum, single salt, mixed salt, osmo-regulated substances, anti-oxidant enzyme system