青海高原植物生理生态学研究——Ⅱ.高寒草甸植物的光合作用

THE PHYSIOLOGICAL ECOLOGY STUDIES ON PLANTS IN QINGHAI PLATEAU Ⅱ. THE PHOTOSYNTHESIS OF PLANTS IN ALPINE MEADOW

青海高原高寒草甸植物柔软紫苑(Aster flaccidus)和糙毛鹅冠草(Roegneria hirsuta),在同一海拔高度(3200m),由于种的不同,净光合速率(Pn)和表观光合量子效率(AQY=1/AQR)也不同。双子叶植物柔软紫苑较单子叶植物糙毛鹅冠草高一些。同一垂穗披碱草(Elymus nutans),而在不同海拔高度(2300m和3200m),由于海拔和气压不同,Pn和AQY也不同。在高海拔地区(3200m),长期生长的垂穗披碱草的Pn和AQY较低海拔地区(2300m)同一植物的低。在青海高原,同一海拔高度的不同植物或不同海拔高度的同一植物,在水分供应充足时,其Pn日变化多呈典型地单峰曲线。在水分供应不足的情况下,其Pn日变化会出现中午降低现象,变化曲线多呈典型的双峰曲线。

The Pn and AQY of different plants in Alpine meadow are difference on the same altitude. The Pn and AQY of Aster flaccidus is higher than Roegneria hirsuta. Whereas,the difference of Pn and AQY or the same plant on different altitude are greater. The Pn and AQY of the same plant in high altitude are lower than that in low altitude. The variation of photosynthesis of different plants in the same altitude is because of difference between species, and the variation of photosynthesis of the same plant in different altitude is connected with atmospheric pressure. The diurnal variation of net photosynthetic rate of different plants on the same altitude or the same plant on different altitude are typical one peak curve during abundance of water supply in the Qinghai Plateau. When serious deficiency of water of plants in Alpine meadow are caused by drought of soil and atmosphere, the midday depression of diurnal variation of net photosynthetic rate would occur. That is to say, the diurnal variation of net photosynthetic rate are typical two peak curve during lack of water supply.