中文摘要：

【目的】研究杨树幼苗生理生长变化与土壤Pb含量的关系及对Pb吸收分布的特征,为利用杨树修复环境提供依据。【方法】选取加拿大杨树幼苗为试材,按土壤中添加Pb的含量不同分成5个组进行盆栽,测量叶绿素含量、净光合速率、POD、SOD、CAT、丙二醛（MDA）、生物量、株高、Pb含量9个生理生长指标,依据杨树幼苗生理生长指标变化特点,将5个组分成无污染、轻度污染和重度污染3个大类别,采用方差分析法、综合相关分析法、矢量综合相关分析法和判别分析法进行分析。【结果】1）随着土壤Pb含量的升高,杨树幼苗的生长指标值（生物量和株高）和正生理指标值（叶绿素含量、净光合速率Pn）随之降低,负生理指标值（SOD、POD、CAT和MDA）则随之升高。2）杨树幼苗的生长指标值与正生理指标叶绿素含量、净光合速率Pn值在土壤Pb浓度〈1 045 mg·kg-1时,各组间基本无显著差异,≥1 045 mg·kg-1时,各组间存在显著差异。负生理指标（SOD、POD、CAT和MDA）正好相反。3）杨树幼苗的生长指标组（生物量、株高）、正生理指标组（叶绿素含量、净光合速率Pn）、负生理指标组（SOD、POD、CAT和MDA）分别在无污染、轻度污染和重度污染3大类别的正确判别率都很高,说明土壤Pb污染含量划分的正确性,能很好地反映杨树幼苗生长生理变化特征。4）杨树幼苗的生长指标组（生物量和株高）和正生理指标组（叶绿素含量、净光合速率Pn）无论是直接相关还是综合相关,都存在显著、极显著的正相关。杨树幼苗的生长指标组（生物量、株高）和负生理指标组（SOD、POD、CAT和MDA）无论是直接相关还是综合相关,都呈显著、极显著负相关。正生理指标和负生理指标间呈显著负相关。5）杨树幼苗根、茎、叶中富集的Pb浓度随土壤Pb含量升高而升高,但根是最主要的吸收部位。除无污染情

英文摘要：

【Objective】In this paper,we aimed at studying the impact of soil Pb on the physiological indicators and growth of Populus seedlings. 【Method 】 Potting seedlings of Populus canadensis were subjected to five different concentrations of the soil lead, and the physiological indicators, including the content of chlorophyll、the net photosynthetic rate（ Pn）,the activity of CAT,POD,SOD,the content of MDA,the height and biomass of plants and the content of Pb,were measured. According to the variation of physiological indicators,the five groups were classified into three categories,no pollution,light pollution and severe pollution. Data were analyzed with the methods of ANOVA,comprehensive correlation analysis, vector comprehensive and correlation analysis as well as discriminant analysis.【Result】Firstly,the growth indicators（ biomass and plant height） and positive physiological indicator（ chlorophyll content,the net photosynthetic rate（ Pn）） of the seedlings were decreased as the concentration of Pb was increased,but negative physiological indicators（ SOD,POD,CAT and MDA） were subsequently increased. Secondly,there were no significant differences in growth and positive physiological indicators among the five groups when the concentrations of Pb were less than 1 045 mg·kg- 1,however,when the concentrations of Pb were more than 1 045 mg·kg- 1,the differences were significant. However,the negative physiological indicators（ SOD,POD,CAT and MDA） were opposite. Thirdly,The correct discrimination rate of growth index,positive and negative physiological indicators in no pollution,light pollution and severe pollution groups was very high,indicating that the partition of Pb concentration was correct,and can well reflect the variation of growth and physiological indicators. Fourthly,the growth（ biomass and plant height） showed significantly positive correlation with the positive physiological indicators（ chlorophyll content,the net photosynthetic rate（ Pn））,but exhibited significan