Alleviation of cold damage by exogenous application of melatonin in vegetatively propagated tea plant (Camellia sinensis (L.) O. Kuntze)

摘要

Melatonin is involve in plant development and abiotic stress responses. In the present study, the effects of exogenous melatonin on chilling in tea plant were investigated. Compared to control, decreasing chlorophyll contents and increasing malondialdehyde levels in leaves were observed in tea plants treated with chilling at 4 degrees C. Interestingly, compared to chilling treatment, chlorophyll contents were increased significantly and malondialdehyde levels were dramatically decreased in tea leaves after melatonin treatments. Moreover, exogenous melatonin enhanced the anti-oxidation ability by increasing the activities of superoxide dismutase, catalase and peroxidase. It was also observed that there is increased the contents of reduced glutathione (GSH), decreased the contents of oxidized glutathione (GSSG), increased the ratio of GSH/GSSG, and increased the activity of ascorbate peroxidase and glutathione reductase in tea leaves after melatonin treatments. Meanwhile, the genes expression of CsGSHS, CsGR, and CsAPX were significantly up-regluated after the treatment of melatonin comparison with chilling treatment. Therefore, these data indicated that exogenous melatonin can attenuate the cold damage via enhancing anti-oxidation ability in tea plant.