Abstract: Tea plant, as one of the plants with high fluorine contents, has fluoride-polymerizing property. In this paper, based on scanning electron microscopy, the roots of ‘Huangdan’ and ‘Foshou’ were treated with different fluoride concentrations (10 mg·L^-1 and 50 mg·L^-1) and different time periods (1 d and 16 d). The differentially expressed gene WSD1 of tea wax synthesis under fluoride treatment was screened from the transcriptome data of our research group. The results show that under 50 mg·L^-1 fluoride treatment, the epidermal cells of ‘Huangdan’ root had slightly more wax on the surface and relatively loose cell arrangement, while the epidermal cells of ‘Foshou’ root had blurred boundaries, significantly more wax on the surface, and fluorine intolerance symptoms such as cell wall distortion and breakage. Quantitative fluorescence results of WSD1 related to wax synthesis show that WSD1 had a significant up-regulation effect on the wax content of tea root under exogenous fluoride treatment. The prediction results of WSD1 protein interaction network and correlation analysis show that WSD1 was negatively regulated by CSS0041298, CSS0012327 and CSS0049082. This study provided a theoretical reference for alleviating fluorine stress in tea plants from the perspective of the interaction between tea plants and wax synthesis, and provided a scientific basis for further exploring the regulation of fluorine absorption in tea plants and the breeding of fluorine-tolerant tea cultivars.

Key words: tea plant, fluorine, SEM, wax synthetic genes