A Comparative Studies On Diurnal Course Of Photosynthetic Of Dominant Plants Of Alpine Meadow At Eastern Qinghai-Tibetan Plateau

The article comparatively studies on diurnal course of photosynthetic of dominant plants Sibiraea angustata, Spiraea alpine, Carex muliiensis, Kobresia setchwanensis of Alpine Meadow at Eastern Qinghai-Tibetan Plateau. The result shows that diurnal course of Photosynthetic rate of Sibiraea angustata, Spiraea alpine, Carex muliiensis both appears typical double-peak curves, and presents photoinhibition, the first and second peak value of Sibiraea angustata is 22.0 and 19.3μmol.m-2.s-1respectively, but that of Spiraea alpine is relatively low, which is 17.8 and 13.5μmol.m-2.s-1, Carex muliiensis is lower, which is 10.9 and 10.3μmol.m-2.s-1. Diurnal course of transpiration rate of Sibiraea angustata and Kobresia setchwanensis appear typical single-peak curves, but Spiraea alpine and Carex muliiensis appear typical double-peak curves. Diurnal course of Fv/Fm andΦⅡPSⅡof Sibiraea angustata, Spiraea alpine, Carex muliiensis and Kobresia setchwanensis are similar, Fv/Fm andΦⅡPSⅡare highest in dawn, and then decrease with increaseing photosynthetic active radiation, reach the lowest about 13: 00, which presents photoinhibition.