中文摘要：

在自然条件下,测定了3种引种杨树和3种乡土杨树苗木叶片的光合气体交换参数和叶绿素荧光参数。3种引种杨树为芬兰山杨A21、芬兰山杨16、加杨,3种乡土杨树为小青杨、小叶杨、兴安杨。其测定结果表明,3种引种杨树苗叶的净光合速率（Pn）显著高于3种乡土杨树,同时蒸腾速率（E）、瞬时水分利用效率（WUE）的平均值也高于3种乡土杨树的苗叶。从而说明3种引种杨树的光合能力较强,对吸收的光能和水分的利用效率较高。3种引种杨树苗叶的初始荧光（Fo）、最大荧光（Fm）、PSⅡ光能捕获效率（F′v/F′m）、稳定荧光（Fs）、光适应下最小荧光产量（F′o）、最大荧光产量（F′m）的平均值均高于3种乡土杨树,3种引种杨树的可变荧光（Fv）、PSⅡ最大光能转换效率（Fv/Fm）、可变荧光与初始荧光之比（Fv/Fo）、PSⅡ电子传递量子效率（ΦPSⅡ）、非光化学猝灭系数（NPQ）、光化学猝灭系数（qP）的平均值均低于3种乡土杨树。相关分析表明,Pn与Tr、Tr与Ci、Fm与Fo、Fv/Fo与Fv/Fm、ΦPSⅡ与Fo均呈极显著正相关（P〈0.01）;ΦPSⅡ与Fm、F′v/F′m与Fv/Fo呈显著正相关（P〈0.05）;Fv/Fo与Fo、Fv/Fm与Fo、NPQ与Fv/Fm、NPQ与Fv/Fo均呈极显著负相关（P〈0.01）;qP与F′v/F′m呈显著负相关（P〈0.05）。

英文摘要：

The gas exchange,chlorophyll fluorescence parameter of three introduced poplars and three native poplars were determined under natural conditions.Three study introduced poplars were Finland poplar A21（Populus tremula×Populus tremuloides）,Finland poplar 16（Populus tremula×Populus tremuloides）and Jiayang（Populus deloides Marsh×Populus nigra L.）,and three study native poplars were Xiaoqingyang（Populus pseudo-simonii）,Xiaoyeyang（Populus simonii Carr.） and Xing＇anyang（Populus hsinganica）.The determination results showed that the net photosynthetic rates（Pn）of the introduced poplars were significantly higher than three native poplars,transpiration rate（Tr）and water use efficiency（WUE）of the introduced poplars were also higher than the native poplars.These results indicated that the phytosynthetic capacity of the introduced poplars were promising,and the efficiency of light and water absorption were also high.The mean values of the initial fluorescence（Fo）,maximal fluorescence（Fm）,actual efficiency of primary conversion of light energy of PS II（F′v/F′m）,stable fluorescence（Fs）,minimum fluorescence of dark adaptation（Fo）and maximum fluorescence of light adaptation（F′m）of introduced poplars were higher than those of native poplars,but the mean values of the variable fluorescence（Fv）,potential efficiency of primary conversion of light energy of PS II（Fv/Fw）,the ratio of variable fluorescence to initial fluorescence（Fv/Fo）,non-photochemical quenching coefficient（NPQ）,quantum yield of PS II electron transport and photochemical quenching coefficient（qP）were lower than that of native poplar.Correlation analysis among photosynthetic parameters showed that there were significant positive correlations between Pn and Tr,Ci and Tr,Fm and Fo,Fv/Fo and Fv/Fm,PS II and Fo（P0.01）,and between PSII and Fm,F′v/F′m and Fv/Fo（P0.05）.However,there were significantly negative correlations between Fv/Fo and Fo,Fv/Fm and Fo,NPQ and Fv/Fo（P0.