盐胁迫下外源褪黑素对烟草幼苗抗氧化特性和光合特性的影响

褪黑素（melatonin, MT）是一种广泛存在于高等植物体内的小分子物质，在植物的生长发育和增强抗逆性等方面都有一定的作用，为明确外源褪黑素对烟草幼苗在盐胁迫下的生理机制，以烟草品种K326作为研究对象，采用水培方式，通过施加不同浓度的外源褪黑素，分析不同处理下烟草幼苗的抗氧化特性和光合特性。结果表明：盐胁迫处理后，烟草幼苗的叶片水分含量下降，破坏了正常的生理状态和光合作用过程，通过施用不同浓度的外源褪黑素处理后，叶片含水率有所恢复，叶绿素含量上升，脯氨酸含量显著增加，过氧化物酶活性显著增加，过氧化氢和丙二醛含量显著下降，光合效率上升，并且褪黑素处理有明显的浓度效应，在100 μmol/L时效果最好，为研究褪黑素的作用机理提供一定理论依据。

Influenes of Exogenous Melatonin on Antioxidant and Photosynthetic Characteristics of Tobacco Seedlings Under Salt Stress

Melatonin (MT) is a small molecule substance widely found in high plants and plays some roles in the growth and development of plants and enhances stress resistance. In order to clarify the physiological mechanism of exogenous melatonin in tobacco seedlings under salt stress, this study took tobacco cultivar K326 as the research object, and adopted water culture method to analyze the anti-oxidation and photosynthetic characteristics of tobacco seedlings under different treatments by applying different concentrations of exogenous melatonin. The results showed that the leaf moisture content of tobacco seedlings decreased after salt stress treatment, which destroyed the normal physiological state and photosynthesis process. After treated with different concentrations of exogenous melatonin, the leaf moisture content recovered and the chlorophyll content increased. Proline content increased significantly, peroxidase activity significantly increased, hydrogen peroxide and malondialdehyde content decreased significantly, photosynthetic efficiency increased, and melatonin treatment had a significant concentration effect, the best effect at 100 μmol/L, which provided a theoretical basis for the study of melatonins mechanism of action.