关键词: 烟草幼苗, 硫化氢, 干旱胁迫, 生理生化特性

Abstract: In order to clarify the alleviating effect of exogenous hydrogen sulfide (H2S) on tobacco seedlings under drought stress, using tobacco variety Yuyan 10 as research object, and sodium hydrogen sulfide (NaHS) as donor of exogenous hydrogen sulfide, this paper studied the effects of different NaHS concentration (0.01 mmol/L, 0.1 mmol/L, 0.4 mmol/L, 0.7 mmol/L, 1 mmol/L) on the physiological and biochemical characteristics of tobacco seedlings under 15% PEG-6000 simulated drought stress. The results showed that: compared with the control, the growth of tobacco seedling under drought stress was significantly affected. Compared with drought stress, the moisture content, chlorophyⅡcontent of tobacco seedling and root vigor, etc. indexes were significantly increased after the pretreatment of adding exogenous hydrogen sulfide, especially the proline content increased significantly. The water absorption and retention of seedlings were strengthened. At the same time, the activities of many antioxidants in body（SOD, POD, CAT, APX）were significantly strengthened. The leaf electrical conductivity, the contents of hydrogen peroxide ( H2O2) and malondialdehyde (MDA) in tobacco seedlings were all decreased, thus reducing the damage to tobacco seedlings caused by rising content of reactive oxygen species (ROS) under drought stress. After pretreating tobacco seedlings with exogenous hydrogen sulfide, the response of various physiological indexes had obvious gradient effect. Results showed that 0.4 mmol/L NaHS treatment had the best effect. Exogenous hydrogen sulfide enhanced the adaptability of tobacco seedlings to drought stress at certain extent, thus providing some basis for improving the drought resistance of tobacco seedlings.

Key words: tobacco seedling, hydrogen sulfide, drought stress, physiological and biochemical characteristics