樟科润楠属植物ITS序列贝叶斯分析及其系统学意义

Bayesian Inference of nrDNA ITS Sequences from Machilus (Lauraceae) and Its Systematic Significance

应用nrDNA Internal Transcribed Spacer(ITS)序列,使用Bayesian分析法对樟科润楠属的系统学问题进行了初步探讨,结果表明润楠属在鳄梨属群中本身作为一独立分支,是一个自然的单系类群;由于其花被裂片果期宿存且强烈反转与同产自亚洲的楠属和油丹属存在清晰界线。本研究否定了前人依据花被片外面被毛情况及果实大小所建立的润楠属属下系统,但同时暗示着花序类型可能是解决润楠属下系统演化的关键性状。本研究对解决润楠属属内种间的系统演化关系尚有不足,建议今后补充更多的属内物种以及寻找新的分子标记进行更深入的研究。

The phylogeny of the genus Machilus was analysed by means of Bayesian Inference of nrDNA ITS sequences. Our results indicated that Machilus is a monophyletic clade within the Persea group, and its persistent and spreading to reflexed tepals on fruit are an important character for its generic delimitation against the related genera Phoebe, Alseodaphne and Persea. This study rejects the former infragenerie systematic arrangement of Machilus based on the pubescence type of tepals abaxially and the size of fruit, but suggests that the type of infloreseenees may be valuable for the understanding of its infrageneric evolution. However, the species relationships within Maehilus are poorly resolved. Samplings of additional taxa from Machilus and more powerful markers are needed in further study.