Abstract:

Ecophysiological responses of Hippophae neurocarpa to elevated CO₂ concentration ([CO₂]were investigated), the leaf by measuring gas exchange, water use efficiency, growth and leaf traits in this experiment. Our results showed that elevated [CO₂] significantly increased the net photosynthetic rate, water use efficiency, and hence enhanced the accumulation of leaf, stem, root and total biomass of H. neurocarpa, with relatively more biomass allocated to aboveground (especially for stem). The specific leaf area, mean single leaf area and nitrogen content decreased by 27%, 33% and 41%, and the carbon/nitrogen ratio significantly increased by 73% under high [CO₂] compared with those under ambient [CO₂]. Overall, those results indicated that increased [CO₂] not only had a significant "fertilizer effect" on photosynthesis, growth and water use efficiency of H. neurocarpa, but also increased an acclimation ability by reducing decreases of specific leaf area, mean single leaf area and nitrogen content, which would confer this species to cope with other extreme environments.

Key words: Hippophae neurocarpa, elevated[CO₂], leaf gas exchange, growth, water use efficiency, leaf traits