Abstract: In the context of global warming, drought has become an important factor restricting the development of crop production, but there were relatively few studies on the physiological and biochemical responses of different tea cultivars to drought stress. Here, a pot water control experiment was conducted using annual tea seedlings of 10 tea cultivars (strains) such as Huangjincha 1 (HJC-1), HPS-8, and HPS-15 as materials. The chlorophyll content, chlorophyll fluorescence parameters and soluble sugar content were studied. The results show that: drought stress shortened the leaf length and width, reduced the number of leaves, increased the number of lateral roots, and dwarfed the plant. Furthermore, leaf thickness, upper epidermal thickness, fence tissue thickness, sponge tissue thickness, lower epidermal thickness and ratio of fence tissue to sponge tissue also decreased under stress. Chlorophyll a, chlorophyll b, and total chlorophyll contents increased compared to the control group, and the increase of chlorophyll a content was significant. Photoinhibition was observed in all tea cultivars (strains) under drought stress. The values of Fo, Fv/Fm and Fv/Fo of tea cultivars under stress were lower than the control group, but the Fm values showed an opposite trend. The soluble sugar content of leaves significantly increased under drought stress compared with the control, except tea cultivar XN-1. Further analysis shows that HPS-8, XN-18, XN-9803, XN-9810 and XN-9809 have low drought tolerance but HJC-1, HPS-15, XN-1, XN-9802 and HPS-20 have relatively strong drought tolerance.

Key words: Camellia sinensis, stress, chlorophyll fluorescence, paraffin section