外源硫化氢对干旱胁迫下烟草幼苗生理生化特性的影响

为明确外源硫化氢（H2S）对干旱胁迫下烟草幼苗的缓解作用，以豫烟10号为研究对象，利用硫氢化钠（NaHS）作为外源硫化氢供体，研究了不同浓度（0.01 mmol/L、0.1 mmol/L、0.4 mmol/L、0.7 mmol/L、1 mmol/L）NaHS对15%PEG-6000模拟干旱胁迫下烟草幼苗生理生化特性的影响。结果表明：与对照（全营养液正常生长）相比，干旱胁迫下的烟草幼苗生长受到了显著的影响，在加入NaHS预处理后，与干旱胁迫相比，烟草幼苗的含水率、叶绿素含量、根系活力等指标显著提高，特别是脯氨酸含量显著增加，提高了幼苗的吸水和保水性，同时体内多种抗氧化物（SOD、POD、CAT、APX）的活性显著增强，叶片电导率、过氧化氢（H2O2）和丙二醛（MDA）含量下降，减小了干旱胁迫导致活性氧（ROS）含量升高对烟草幼苗带来的伤害。干旱胁迫下的烟草幼苗经过NaHS预处理后，各项生理指标反应有明显的梯度效应，表明0.4 mmol/L NaHS处理效果最佳，外源硫化氢可在一定程度上增强烟草幼苗对干旱胁迫的适应能力。

Effects of Exogenous Hydrogen Sulfide on Physiological and Biochemical Characteristics of Tobacco Seedlings under Drought Stress

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.