Effect of selenium on tea (Camellia sinensis) under low temperature: Changes in physiological and biochemical responses and quality

Abstract Tea is a high-value cash crop, and it is a popular beverage globally owing to its unique flavor and health benefits. Selenium can increase tea yield, and the increasing demand for selenium-enriched tea has made it a research hotspot. However, the effect of selenium on the quality and cold resistance of tea has rarely been studied. The purpose of this study was to examine the effects of exogenous selenium application on the physiological and biochemical properties, antioxidant enzyme activity, and quality of tea under low-temperature stress (4℃). The results showed that selenium treatment increased the net photosynthetic rate of leaves under low-temperature stress. Furthermore, it reduced the contents of malondialdehyde and hydrogen peroxide to stabilize plant photosynthesis and the membrane system and to improve the cold tolerance of tea. Moreover, selenium treatment increased the activity of superoxide dismutase, peroxidase, ascorbate peroxidase, and catalase through regulating proline and increasing the activity of ascorbate peroxidase and catalase to prevent oxidative damage caused by cold stress. In addition, treatment with selenium regulated changes in the secondary metabolites of tea under low-temperature stress, including reducing the oxidation products of polyphenols, increasing the polyphenol content, increasing sugar accumulation, and promoting the synthesis of various tea amino acids to improve tea quality.