Abstract: In this study, desert halophyte Limonium aureum(Linn.) Hill was used to investigate the changes of osmolyte content, reactive oxygen species production and antioxidant enzyme activities in the leaves of seedlings under different NaCl concentrations. The levels of proline, soluble sugar and H₂O₂ as well as the rate of O₂^-· production increased in the seedlings treated with different NaCl concentrations. Compared with the control, the amount of soluble protein decreased in the leaves of seedlings treated with 25 and 50mmol·L^-1 NaCl, but enhanced under 100 and 150 mmol·L^-1 NaCl treatments. Additionally, all applied NaCl concentrations resulted in the enhancement of superoxide dismutase (SOD) and ascorbate peroxidase (APX) activities. In contrast, the activity of peroxidase increased at first and then decreased, but significant decrease in catalase activity was observed in the leaves of L.aureum treated with NaCl, as compared with the untreated seedlings. These results indicated that the accumulation of osmoregulation substances and the enhancements of SOD and APX activities in response to salt stress elevated the osmotic adjust action and the oxidation resistance ability in the leaves of L.aureum, which might be associated with the elevation of plant tolerance to salt condition.

Key words: salt stress, Limonium aureum(L.) Hill, osmolytes, ROS, antioxidant enzymes