西藏两种杨树光合特性及其释氧价值评估

采用Li-Cor-6400光合仪对藏川杨和北京杨的日光合特性进行测定，结果表明：藏川杨和北京杨的日光合进程均表现为双峰曲线，藏川杨与北京杨的净光合速率日变化最大峰值均在14：00出现，分别为16.62μmol/（m^2·s）和15.52μmol/（m^2·s）；两种杨树的蒸腾速率日变化均呈单峰曲线，峰值均出现在12：00，藏川杨峰值为8.47 mmol/（m^2·s），北京杨峰值是8.74 mmol/（m^2·s）；单株藏川杨的年释氧生态价值高于北京杨，分别为348元和210元。

Valuation on Photosynthetic Characteristics and Oxygen Release of Two Kinds of Poplar in Tibet

Diurnal photosynthetic characteristics of Populus szechuanica and Populus beijingensis were measured by using Li-Cor-6400 photosynthesis system. The results showed that：Daily photosynthetic process of both kinds of Poplar showed bimodal curve,diurnal variation peak of net photosynthetic rate of Populus szechuanica and Populus beijingensis appeared in 1 4：00,the peak data were 1 6.62 μmol/（m^2 · s）and 1 5.52 μmol/（m^2 ·s）,respectively. Diurnal variation of transpiration rate of two poplar both showed single peak curve,and peak were 8.47 mmol/（m^2 ·s）and 8.74 mmol/（m^2 ·s）,respectively,occurred at 1 2：00,Annual oxygen releasing ecological value per tree of Populus szechuanica was higher than that of Populus beijingensis,which was 348 yuan and 21 0 yuan.