基于ITS序列的东亚当归属植物的分类学研究

Taxonomic study of Angelica from East Asia: Inferences from ITS sequences of nuclear ribosomal DNA

采用PCR直接测序法,测定了东亚地区狭义当归属Angelica s.s.及其近缘共7属40种代表植物的核糖体DNA ITS序列,并结合GenBank中相关植物的ITS序列(含外类群3种),应用遗传距离与系统树分析法对东亚地区狭义当归属植物内部以及当归属与其近缘属植物之间的亲缘关系进行了分析。结果表明:(1)广义当归属中的狭义当归属、柳叶芹属Czernaevia和高山芹属Coelopleurum之间的亲缘关系较近,山芹属Ostericum与它们的亲缘关系较远,这与果实形态、化学分析的结果一致,建议将山芹属作为一个相对独立的分类群处理。(2)ITS序列分析结果支持狭义当归属不是单起源的自然分类群,而应该被分成若干组的观点。(3)ITS序列以及化学成分分析结果表明,前胡属Peucedanum与狭义当归属之间的亲缘关系很近。(4)形态、化学成分以及ITS等多方面分析结果显示,当归A.sinensis与狭义当归属的多数植物之间均有一定的差距,其归属问题值得商榷。(5)ITS序列与化学成分的分析结果均显示藁本属Ligusticum不是一个自然类群。

In order to resolve the relationships among species from Angelica s.s. and its allied genera in East Asia, ITS （Internal Transcribed Spacer） sequences of 44 taxa were used to analyze their sequence divergence and to construct three phylogenetic trees in this paper. Three taxa were used as the outgroup. Some conclusions could be achieved as follows. （1） Angelica s.s., Czernaevia, and Coelopleurum were closely related, but the relationship between Ostericum and them was ulterior. It was also supported by analyses on fruit anatomy and chemical constitutes. Ostericum was proposed as a relatively independent genus. （2） Results from ITS sequences supported the view that Angelica s.s. was monophyletic and could be divided into several sections. （3） Results from ITS sequences and chemical constitutes indicated that the relationship between Peucedanum and Angelica s.s. was very close. （4） Results from ITS sequences as well as from conformation and chemical constitutes showed that the divergence of A. sinensis from other taxa of Angelica s.s. was great. The taxonomic position ofA. sinensis should be reconsidered. （5） Both analyses of ITS sequences and chemical constitutes revealed that Ligusticum was not a natural group.