矮嵩草光合作用与环境因素关系的比较研究

 以青海高原不同海拔地区生长的矮嵩草(Kobresia humilis)为材料，研究高山植物光合作用随海拔梯度的变化特征及对生长环境和低温胁迫的反应。随海拔升高矮嵩草叶绿素含量有降低的趋势，而叶绿素a／b值和类胡萝卜素含量则随海拔升高而增高。生长地区海拔越高矮嵩草光合速率、光补偿点、光饱和点越高；而光合表观量子产额则随海拔升高而降低。光呼吸强度有随海拔升高而降低的趋势。矮嵩草光合作用特性受生长环境因素的影响。低温胁迫导致矮嵩草光合速率、表观量子产额降低，低温下的光照加剧了光合作用抑制的程度。

A COMPARATIVE STUDY OF PHOTOSYNTHETIC RESPONSE OF KOBRESIA HUMILIS TO DIFFERENT ENVIRONMENTAL FACTORS

The photosynthesis and its response of Kobresia humilis, which were obtained from different altitudes in Qinghai Plateau, to the glowing environmental conditions and cold stress were studied. The results showed that the chlorophyll content in the K. humilis leaves tended to decrease with increasing altitude, but the chlorophyll a to b ratio and the carotenoid content increased. The photosynthetic rate, light compensation point and light saturation point increased with the increase of altitude, and the photorespiration rate declined. The photosynthetic apparent quantum yield of K. humilis grown in the culture room (PAR: 60—70 μmol·m-2·s-1 mean day/night temperature: 15℃/10℃) was higher than that grown in the green house (PAR. highest 1250 μmol·m-2·s-1; mean day/night temperature: 24℃/13℃), whereas the photosynthetic rate and Hill Reaction rate were the opposite. The optimum photosynthetic temperature varied with the growing temperatures and the original growing altitudes. The photosynthetic rate and apparent quantum yield of K. humilis decreased after being subjected to cold stress. The cold stress was more inhibitive to the photosynthetic rate under light (90—100 μmol·m-2· s-1) than under dark conditions.