树种蒸腾作用、光合作用和蒸腾效率的比较研究

 各树种在年生长季不同测期的蒸腾速率日进程曲线一般呈单峰型。蒸腾速率与环境因子的相关性大小依次为：光照强度、气温、相对湿度和大气水势。蒸腾速率日变化一般可用具有光照因子的优化模型(即光照型、光温型、光湿型和光温湿型)来模拟。年生长季树种蒸腾速率(g·g-1LD·h-1)排序由大到小为：柠条(0.9269±0.2089)(平均值±标准差，以下同)、小叶杨(0.7177±0.2410)、河北杨(0.6256±0.1609)和北京杨(0.6007±0.2749)；净光合速率(mgCO2·g-1LD·h-1)排序自高至低为：柠条(14.5949±4.6627)、小叶杨(13.4055±2.9994)、河北杨(13.2569±4.3531)和北京杨(11.6989±2.5884)；蒸腾效率(gDM·g-1H2O)排序由高至低为：北京杨(1.41％±0.42％)、河北杨(1.35％±0.36％)、小叶杨(1.26％±0.23％)和柠条(1.00％±0.27％)。

A COMPARISON OF TRANSPIRATION, PHOTOSYNTHESIS AND TRANSPIRATION EFFICIENCY IN FOUR TREE SPECIES IN THE LOESS REGION

The diurnal course of transpiration rate generally showed a pattern of single peak and had a close relationship with Li (light intensity) in the species: P, hopeiensis, P. simonii,P, beijingensis and C. korshinskii. The four sorts of optimal models of transpiration rate consisted of the independent variable of Li; the independant variables of Li and T(temperature),the independent variables of Li and RH(relative humidity),and the independant variables of Li, T and RH, respectively. These four species had the transpiration rates (g·g-1LD·h-1) in the following order: C. korshinskii ( 0.9269 ± 0.2089 ) (mean ± 1 SD ) > P. simonii ( 0.7177 ± 0.2410 ) > P. hopeiensis (0.6256 ± 0.1609) >P. beijingensis (0.6007 ±0.2749); the net photosynthesis rate (mgCO2 ·g-1LD·h-1) was C. korshinskii(14.5949±4.6627)>P.simonii(13.4055±2.9994)>P. hopeiensis (13.2569 ±4.3531) > P. beijingensis (11.6989 ± 2.5884); and the transpiration efficiency (gDM·g-1H2O) was P. beijingensis (1.41% ± 0.42%)>P. hopeiensis(1.35%±0.36%)>P.simonii (1.26%±0.23%)>C. korshinskii (1.00%±0.27%).