Ecophysiological responses of Hippophae neurocarpa to elevated CO2 concentration ( [ CO2 ] wererninvestigated) , 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.%通过测定CO2浓度倍增条件下肋果沙棘幼苗气体交换特征、水分利用效率、叶片性状和生长特性,研究青藏高原特有种肋果沙棘对大气CO2浓度升高的生理生态响应.结果表明:CO2浓度倍增可显著提高肋果沙棘幼苗的净光合速率、水分利用效率,促进幼苗营养器官(根、茎、叶)生物量和总生物量的积累,且肋果沙棘趋于向地上部分(尤其是茎)分配更多的干物质.CO2浓度倍增使肋果沙棘幼苗比叶面积、平均单叶面积、叶片氮含量分别降低27％,33％和41％,碳氮比增加73％,而叶片碳含量无显著影响.CO2浓度升高条件下肋果沙棘幼苗不仅通过增加光合能力、水分利用效率和生物量累积产生明显的“施肥效应”,而且通过降低比叶面积、平均单叶面积和叶片氮含量表现出较强的下调适应能力,进而有利于其应对更为复杂的生存环境.
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