链格孢属(丝孢纲)数值分类研究初探

聚类分析树状图上Alternarla与其相似属Ulocladium、Stemphylium的种明确地分为三个表观群。36个OTU's,23个链格孢属的种,进一步形成四个清晰的亚表观群,恰与椐分生孢子喙的特征而划分的组,即无喙组、假喙组、真喙组和锥状真喙组相吻合。本试验系统中,相似属间、种间和种内的相似性值是在具体试验条件下确定的。其意义在于通过对大量有用分类信息的综合比较分析,以相似性值的形式,为不同等级单位分类地位的确定提供相应定量化的标准,从而能够比较全面地评价一个分类单位.根据研究结果,建议将Alternariamali Roberts作为细链格孢的一个分化型,即Alternarin tenuis C.G.Nees f.sp.,mali。

A PRELIMINARY STUDY OF NUMERICAL TAXONOMY OF THE GENUS ALTERNARIA (HYPHOMYCETES)

The species of Alternaria and its similar genera,Ulocladium and Stem- phylium,were clearly clustered into three apparent groups on dendrogram of cluster analysis. 36 OTU's,23 species of Alternaria were further divided into 4 subapparent groups.They were precisely identical with the groups divided on the basis of their conidial rostrum characters,i.e. Erostratae,Pseudorostratae,Eurostratae and Cone-rostratae.The similarities of inter-genera, inter-and intra-species were determined under concrete experimental conditions and were inf- luenced by the composition ond number of OTU's and the selected characters used in taxonomic studies,etc.Its remarkable significance is to provide a quantitative criterion for the identifi- cation and assessment of certain taxa.A new forma specialis,Alternaria tenuis C.G.Nees f. sp.mali was suggested.