<正>对内蒙古鄂尔多斯地区4个公路段土壤中的重金属元素（Pb、cd、Cr、cu、Hg、Zn、Ni）和类金属（As、se）污染特征进行研究。结果表明：4个公路段都存在不同程度的土壤重金属污染，相对污染程度最低的东胜段公路而言，树林召段公路土壤中铬（cr）存在显著性污染，棋盘井段公路土壤中汞（Hg）存在显著性污染，薛家湾段公路土壤中铬（Cr）和类金属砷（As）存在显著性污染。通过分析发现，虽然机动车辆的尾气排放能够造成公路土壤中的重金属污染，但是此次调查的4个公路段土壤中的重金属污染来源主要是机动车辆运载煤时的煤尘飘落以及当地的工业排废。所以应该以加强对运煤车辆管理和工业污染源的控制为着力点，治理和降低公路绿化及公路旁耕地中重金属污染。

Genetic relationships were studied among 23 isolates of Sphaeropsis sapinea collected from China, United States, England, South Africa and Chile by using RAPD analysis method. 135 scorable DNA fragments were amplified with twelve random primers by PCR (Polymerase Chain Reaction) technique and the polymorphic score was 96.3%. The genetic dendrogram based on RAPD analysis showed that the all S. sapinea isolates could be clustered into three groups. The isolate CWS41 from Chile was separated genetically as a first group away from other isolates, and isolates F2 and J2 from China were as the second group. The third RAPD group accommodated other rest isolates (including B morphotype CWS43 from United States).