关键词: 褪黑素, 烟草, 抗氧化, 光合作用

Abstract: 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.

Key words: melatonin, tobacco, antioxidant, photosynthesis