Interactions of elevated CO2 concentration and drought stress on photosynthesis in Eucalyptus cladocalyx F-Muell.

Response of net photosynthetic rate (P-N) Stomatal conductance (g(s)), intercellular CO2 concentration (c(i)), and photosynthetic efficiency (F-v/F-m) of photosystem 2 (PS2) was assessed in Eucalyptus cladocalyx grown for long duration at 800 (C-800) or 380 (C-380) mu mol mol(-1) CO2 concentration under sufficient water supply or under water stress. The well-watered plants at C-800 showed a 2.2 fold enhancement of P-N without any change in g(s). Under both C-800 and C-380, water stress decreased P-N and g(s) significantly without any substantial reduction of c(i), suggesting that both stomatal and non-stomatal factors regulated P-N However, the photosynthetic efficiency of PS2 was not altered.