Abstract: A.cristatum is one of C₃ sun herb that photosynthetic rate is higher and adaptability on temperature is stronger.Its light saturation point and photosynthetic rate are higher that are near to upper limit of general C₃ sun herb;light compensation point and CO₂ compensation point are lower that about close to lower limit of common C₃ sun herb;range of optimum temperature is wider,19-28℃;compensation point of high temperature is about 63℃ that far go beyond the bounds of C₃ herb in the appropriate condition.2.As compared with constructive species in typical steppe zone,C₃ herb Leymus chinensis ,compensation point of soil water of A.cristatum is lower,the change ratio of the characteristic index of photosynthetic ecology is smaller when the sufficient soil moisture became deficit,these prove that its ability of drought resistance is stronger,maximum photosynthetic rate of A.cristatum is higher and CO₂ compensation point is lower,these mean that use ability of A.cristatum on CO₂ is higher.In addition,differences of light saturation point and of light compensation point of two plants are not obvious,these show that adaptability of two plants on light is roughly the same.

Key words: Agropyron cristatum, Photosynthetic rate, Ecological factor

摘要： 冰草属于C₃阳性草本植物中光合效率较高,对温度适应性较广的一类。在适宜条件下,光饱和点和光合速率较高,接近一般C₃阳性植物的上限,其光补偿点和CO₂补偿点较低,在C₃阳性植物的下限。最适温度范围较宽,为19-28℃,高温补偿点高达63℃,远远超出C₃阳性草本植物的范围。与C₃植物羊草比较,冰草的土壤水分补偿点较低,当土壤由湿变干时,光合生态特性指标的变化率较小,表明其耐干旱能力较强。冰草的温度饱和点较低,高温补偿点较高,最适和适宜温度范围较宽,表明对温度的适应性较广。冰草的最大光合速率较高,CO₂补偿点较低,表明对CO₂的利用能力较强。此外,两种植物的光饱和点和光补偿点差异不明显,说明二者对光的适应性较为一致。

关键词: 冰草, 光合速率, 生态因子