| In this paper, 10% PEG was used to simulate drought stress, thereby studying the effects of exogenous hydrogen sulfide on the activities of antioxidant enzymes (SOD, POD, CAT and APX), the indexes related with membrane lipid peroxidation (MDA and the permeability of cell membrane) in the roots and leaves and the carotenoid content in leaves of maize seedlings under drought stress. The results showed that, compared with drought stress alone, 0.01、0.1、0.3、0.6 mmol·L-1 and 1.0 mmol·L-1 NaHS increased carotenoid content in leaf by 33.3%, 63.3%, 96.6%, 80.0%, and 26.6%, respectively. Compared with drought stress alone, 0.01, 0.1, 0.3, 0.6 mmol·L-1 and 1.0 mmol·L-1 NaHS increased the POD activity in leaf by 14.5%, 36.6%, 50.3%, 91.1% and 80.1%. Besides, pretreatment with 0.01、0.1 mmol·L-1 and 0.3 mmol·L-1 NaHS can significantly improve the activities of SOD and CAT in leaves, the POD activity in root and APX activity in root and leaf. Meanwhile, pretreatment with 0.01, 0.1 mmol·L-1 and 0.3 mmol·L-1 NaHS reduced the permeability of cell membrane and the MDA content in root and leaf. 0.6 mmol·L-1 NaHS could improve the activities of SOD and CAT in leaves and the activity of POD in root by 7.4%、16.3% and 45.0%, respectively. Meanwhile, 0.6 mmol·L-1 NaHS reduced the permeability of cell membrane of root and the MDA content in leaf by 12.0% and 18.0%, respectively. However, 1.0 mmol·L-1 NaHS reduced the activity of APX in root and leaf by 13.3% and 34.9%, respectively. Due to the decrease in the APX activity, 1.0 mmol·L-1 NaHS increased the permeability of cell membrane of leaf and the MDA content in root by 130.1% and 10.5%, respectively. Collectively, these results suggest that pretreatment with low concentrations of hydrogen sulfide can effectively improve the antioxidant capacities of maize seedlings under drought stress, especially for 0.3 mmol·L-1 NaHS. |