<正>对来自中国、美国、英国、南非和智利的松枯梢病菌23个菌株进行RAPD分析。用12个引物共扩增出135个RAPD标记，其中多态性标记占96.3%。各菌株间的Nei相似系数UPGMA法聚类结果表明，国内外23个菌株可大致分为3个类群：来自智利的CWS41与所有菌株的遗传关系最远；来自中国的F2和J2次之；其他的国外菌株与国内菌株的遗传关系则较近。此次实验未将来自美国的B型菌株与其他菌株区分开。

This study deals with the content of heavy metals such as Cu,Pb,Cr,Zn,Cd of forest litter in Nanjing urban forests. The results showed that the heavy metal content in forest litter was higher than that of soil background value and the plant content value of above ground part, the heavy metal content of different layers was Y layer>L layer, the order of heavy metal content in different plots was: urban district and outer suburbs>city suburbs, the coefficient of variation of different communities was between 17.91% and 63.47%, the order of different heavy metal content in forest litter was:rn(Zn)>m(Cr)>m(Pb)>m(Cu)>m(Cd), the content of Zn is 0. 909 2 kg/hmz.