Abstract: The net photosynthesis(Pn), transpiration(Tr), stomatal conductance(Sc), water use efficiencyβ(WUE), chlorophyll contents and nutrient elements content of tea plant under ambient and elevated CO₂ conditions were measured, and responses to elevated CO₂ were discussed. The results showed that Pn increased by 17.9% and 25.8% under elevated (550 and 750μmol·mol^-1)CO₂, compared to the ambient air CO₂ concentration. At the same time, midday depression of photosynthesis abated or disappeared. Sc reduced by 7.6% and 13.0% and Tr decreased slightly. WUE increased by 21.6% and 35.8%. It was also found that chlorophyll a, chlorophyll b, total chlorophyll and carotennoid contents increased by 12.8%~18.4%, 14.0%~22.0%, 13.1%~19.4% and 17.2%~20.1% in shoots of tea plant. However, the ratio of chlorophyll a to b reduced. The N, K, and Ca contents in shoots decreased to some extent. The Mg, Fe, Zn, Mn and Cu contents increased with CO₂ enrichment.

Key words: Eleveted CO₂, Tea plant, Net photosynthesis, Stomatal conductance, Chlorophyll