大气CO_2倍增对草原羊草的影响

Effects of Doubled CO 2 Concentration on Leymus chinensis in Grasslands .

羊草（Ｌｅｙｍｕｓｃｈｉｎｅｎｓｉｓ）是亚洲东部草原地带性植被的优势植物之一。羊草群落在我国广泛分布于东北和内蒙古东部，是该地重要的放牧场和割草场。羊草已广为栽培并建立了人工草地，是家畜优质的饲料植物。关于在自然条件下草原地区羊草的生长发育节律、光合...

The ecophysiological effects of doubled CO 2 concentration on Legmus chinensis which is a good herbagae in grasslands were studied.The results showed that doubled CO 2 concentration could promote the physiological process of Leymus chinensis ,such as:increassing net-photosynthesis rate and water use ratio and reducing water loss of leaf . It specifically showed that the stomatal resistance increased 4% to 13%, the transpiration rate reduced 6% to 13%, the Net-photosynthesis rate increased 49% to 87%,and the water use efficiency increased 65% to 101%. This kind of increase trend could continuously appear in every phenological period. This indicated that the Net-photosynthesis rate of the Leymus chinens is did not produce downward“acclimation”under high concentration of CO 2 within a vegetative season. Doubled CO 2 concentration made the physiological process active and accelerated its phenological couse as well. The changes of physiological and biological characteristics mentioned above were mutually affected and promoted. Doubled CO 2 concentration increased the biomass of the Leymus chinensis . Dry matter weight above ground increased 10.4% to 23.2%, the root increased 48.4%. Root/shoot ratio is obviously increased. In general, the physiological effect of doubled CO 2 concentration on the Leymus chinensis was positive and could increase bioproductivity.