Melatonin treatment promotes cold adaptation and spring growth of tea plants

Cold stress can seriously affect the yield and quality of spring tea, ultimately leading to decreases in the economic benefits of tea production. Although melatonin can enhance the cold resistance of young tea plants indoors, its effects on mature tea plants in tea gardens and on the spring tea yield and quality remain unknown. In this study, we determined the optimal exogenous melatonin treatment concentration (100 µmol/L) and revealed that an exogenous melatonin treatment for 2 months can protect mature tea plants (Camellia sinensis cv. ‘Yinghong No. 9’) in tea gardens from cold stress. Following the application of exogenous melatonin, the quality of spring tea was not significantly affected, and the growth of spring tea was stimulated. Combining the melatonin and cover treatments was more effective in promoting spring tea growth. The study results may be used to further increase the yield and preserve the quality of spring tea under cold stress conditions.