摘要
青海高原主要 C_3植物叶片的净光合速率(Pn)日变化是随着自然条件下的日照和气温的变化而变化,呈典型的单峰曲线,无或有轻微的中午降低现象。表观量子需要量(AQR)在晴天的上午和下午基本不变,一天中不曾出现显著的光抑制现象。然而,在土壤严重缺水和气温超过30℃以上时,青海高原主要 C_3植物净光合速率的日变化仍呈双峰曲线。在一般情况下,青海高原主要 C_3植物的光补偿点和暗呼吸速率较低。光饱和点和表观量子需要量较高。因而,表观光合量子效率(_i=1/AQR)较低,这与青藏高原高海拔地区的低气压有关。
The biological yield is bound up with photosynthesis.Though the air temperature on Qing- hai plateau is very low,yet the intense solar radiation on the plateau and of the long sunshine hours are favourable to photosynthesis.While the air temperature is very high,it may cause the photosynthesis to midday depression in the areas of low elevation.However,this does not occur on alpine meadow in Qinghai plateau.Diurnal variation of net photosynthetic rate(Pn)of plant leaves in alpine meadow under natural environmental conditions depends on the change of air temperature and solar radiation intensity.It gives a typical curve with one peak.None or little midday depression of net photosynthetic rate was observed.The apparent quantum re- quirement(AQR)of plant leaves in alpine meadow under natural environmental conditions re- mains constant in the morning and afternoon on fine days,which indicated that no signifi- cant photoinhibition occurred.However,diurnal variation of net photosynthetic rate of plateau plant still revealed as of double peak when soil is seriously lack of water and air temperature is 30℃ or over.Under general conditions,the light compensation point and dark respiration rate in plant of alpine meadow are lower.The light saturation point and the apparent quantum requirement are higher.Therefore the apparent quantum efficiency is lower.This is related to low atmospheric pressure in the areas of high elevation on Qinghai plateau.
基金
中国科学院海北高寒草甸生态系统定位站和国家自然科学基金
关键词
C3植物
光合作用
净光合速率
Net photosynthetic rate
Apparent quantum requirement
