Determination of photosynthetic parameters Vcmax and Jmax for a C3 plant (spring hulless barley) at two altitudes on the Tibetan Plateau

摘要: On the Tibetan Plateau, unique alpine climate factors of low air pressure, CO(2) partial pressure and temperature have significant but non-explicit influences on photosynthetic capacity plants. To evaluate these influences, we measured net rates for spring hulless barley leaves at two altitudes 3688 m (the altitude) 4333 high altitude), respectively. Two parameters-Vc(max), maximum rate Rubisco carboxylase activity, J(max) electron transport-were determined. The parameters Vc(max) were higher from plants grown altitude than those altitude. approximately 24% 22% greater, respectively, lower As a consequence, exposed to Plateau. optimal temperatures 6.5% 3.5% higher, in altitude, ratio was 12.7% Simulation analyses revealed that capacities decreased after long-term increases associated with global change