Abstract: Tea plant was cultivated in Hoagland nutrient solution containing 0.5βmmol/L Cd²⁺ for 8 days. Tea leaves lost their green color gradually with the change in the ultrastructure of the chloroplast . At the early stage, there was a slight decrease in the number of granum thylakoids. Then, the thylakoids piled up loosely, and chloroplasts rounded off to different extents. At the late stage , the structure of the chloroplast related to thylakoid became unclear, while the thylakoid system was disintegrated abnormally with a few single bent and swell thylakoids, and some ruptured envelope of chloroplast. Cadmium ions significantly inhibited the photosynthesis activity and led to the decline in the chlorophyll content and chlorophyll a/b ratio. Further more the photochemical efficiency of PSII（Fv/Fm）and the potential activity of PSII（Fv/Fo）decreased in different degrees with increasing Cd²⁺ stress . The pollution duration resulted in the damage of photosynthetic structure in tea leaf cells.

Key words: Camellia sinensis, Cadmium ions, Chlorephyll fluorescence kinetics, Photosynthesis, Ultrastructure