<正>对内蒙古西部地区国道公路旁侧土壤与植物中重金属（Cd、Hg、Pb、Cu、Zn、Ni、Cr、As和Se）含量以及土壤重金属（Cu、Zn、Ph、Ni、Cr）形态进行测定，分析了公路旁侧土壤和植物油松（Pinus tabulae formis）、小叶杨（Populus simonii）中重金属元素含量特征，分析该区域土壤的重金属分布状况以及重金属的生物有效性。结果表明：Cd、Pb、Cr、Ni、Cu、Zn、Hg、As、Se的含量随距公路垂直距离的分布并不是简单的线性负相关关系。土壤重金属元素的吸附及污染程度以cd为最高，土壤中Cd、Pb含量偏高可能因为机动车辆运行导致向公路两旁释放Cd、Pb元素，并在土壤中沉积所致。重金属在植物体不同器官中的含量存在一定差异。植物的根部和茎叶中重金属的含量均表现出”N”字形变动趋势。重金属元素有效态占总量百分比的大小序列与重金属元素在不同植物不同器官中的含量大小序列基本相同，5种重金属元素有效态占总量百分比的大小序列为：c（Zn）>c（Pb）>c（Ni）、c（Cr）>c（Cu），与重金属元素在不同植物不同器官中的含量大小序列趋于一致。

Cellulase-poor xylanase was used to pretreat wheat straw pulp in order to study its reduction effects on the Cl2 consumption and its influence on the variation of lignocellulosic components during CEH bleaching process. The results indicated: After xylanase pretreatment, the Clz dosage could be decreased by 50% without affecting the targeted brightness. Xylanase pretreatment had removal effects on lignin of the pulp and could boost the dissolving of lignin during alkali extraction process. However, xylanase showed various degrees of depolymerization on pentosane and cellulose. The final lignin and pentosane content after bleaching of the enzyme-treated pulp were slightly lower than that of the control, whereas cellulose content was a little higher than that of the control.