| Effects of different concentrations of exogenous hydrogen sulfide were studied on the physiological characteristics of maize seedlings under drought conditions. The results showed that pretreatment with 0.01 mmol·L-1 NaHS could significantly increase relative water content (RWC), proline content in root and leaf, chlorophyll content and soluble sugar and soluble protein content in root, but this had no significant effects on soluble sugar content and soluble protein content in leaf under drought stress. Pretreatment with exogenous 0.1 mmol·L-1 and 0.3 mmol·L-1 NaHS could significantly increase RWC, proline contents in root and leaf, chlorophyll content, soluble protein and soluble sugar content of root and root activity, but these had no significant impacts on soluble sugar content and soluble protein content in leaf under drought stress. Pretreatment with 0.6 mmol·L-1 NaHS could significantly increase RWC of root and leaf, chlorophyll A content, soluble sugar content, soluble protein contents in leaf and root activity, but this had no significant effects on proline content, soluble protein in root and chlorophyll B content. Pretreatment with 0.6 mmol·L-1 NaHS significantly reduced soluble sugar and proline contents in root under drought stress. Pretreatment with 1 mmol·L-1 NaHS could significantly increase root RWC, soluble protein content and root activity, but this had no significant effects on leaf relative water content, soluble protein and chlorophyll A content. Pretreatment with 1 mmol·L-1 NaHS could significantly reduce soluble sugar and proline content in root and leaf, and chlorophyll B content under drought stress. Our results suggested that low concentrations of exogenous hydrogen sulfide could maintain the water balance and increase the drought-resistance of plant through increasing the contents of osmoregulation substances. |