Abstract: This study was to investigate the physiological response of tea cultivar Longjing 43 seedlings to different aluminum (Al) concentrations by hydroponic culture. The results revealed the biomass increment, relative growth rate (RGR) and electron transfer efficiency (ETR) of the tea plants under low Al concentrations (0.2 and 0.4βmmol·L^-1) were significantly higher than the control group. However, The MDA content in roots showed an opposite trend. As Al concentration continued to increase, the increase rate of ETR began to decline and the growth rate became flat but still a great number of fresh roots were coming up. When Al concentration was higher than 1βmmol·L^-1, the efficiency of light energy conversion in PSⅡ(Fv/Fm) and ETR showed dramatic decline. Meanwhile, RGR decreased and the growth of tea plant was also inhibited. Simultaneously, the results of Al contents in the different tissues of tea plants followed lateral roots, mature leaves > stems > main roots > young leaves. More Al was found in the lateral roots with Al concentration increasing. The study suggested that when Al concentration was lower than 1.0βmmol·L^-1, it could promote the growth of tea plants, but the growth would be inhibited under an Al-free environment or the Al concentration was higher than 1 mmol·L^-1. These results laid a foundation for further study on the physiological mechanism of how Al would promote the growth of tea plants.

Key words: aluminum, tea plant, physiology response, promote growth