关键词: 褪黑素, 盐胁迫, 芦苇幼苗, 生理特性

Abstract: In order to reveal the physiological mechanism of exogenous melatonin improving the resistance to salt stress of Phragmites communis L.,  0.01 mmol/L exogenous melatonin was applied to P. communis seedlings stressed with 150 mmol/L NaCl. The physiological characteristics, including dry matter accumulation, photosynthetic characteristics, antioxidant enzyme activities, osmotic adjustment content and malondialdehyde (MDA) content of P. communis seedlings were tested. The results showed that salt stress inhibited the growth and dry matter accumulation of P. communis seedlings, and caused serious physiological damage to seedlings. Spraying exogenous melatonin could increase the chlorophyll content and photosynthetic performance of P. communis seedling leaves, and increase the activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) and the content of osmotic adjustment substances, such as proline and soluble protein, reduce the content of reactive oxygen and MDA. Therefore, foliage application of melatonin could increase antioxidant enzymes activity and the accumulation of osmotic adjustment substances in the leaves of P. communis under salt stress, and effectively remove excess reactive oxygen species, alleviate oxidative damage and enhance the salt tolerance of P. communis seedlings.

Key words: melatonin, salt stress, reed seedlings, physiological characteristics