基于三个DNA片段讨论菖蒲科的分子系统学

菖蒲属长期以来被置于天南星科，但近年来分子系统学的研究表明菖蒲属与天南星科的关系较远，应成立一个单型科，即菖蒲科（Acoraceae)。本文选择菖蒲科3个种及1个变种即金钱蒲（Acorus gramineus)，石菖蒲（A.ttrinowii)。金边菖蒲（A.tatarinowii)，金边菖蒲（A.tatarinowii var.flawo-marginatus)和菖蒲（A.calamus)不同染色体倍性的4个居群进行了核糖体RNA内源转录间隔段（ITS）进行测序。并据此讨论了菖蒲属的属下系统关系，结果表明，菖蒲科为一个自然的单系类群，不同倍性的菖蒲构成一个自展数据支持率为100%的分支，无中肋的金钱蒲，石菖蒲和金边石菖蒲构成另一个自展数据支持率为100%的分支，通过比较分析菖蒲科与其相关类群之间18S和rbcL两段DNA序列，对菖蒲科的系统位置进行了讨论，在基于18S和rbcL的系统树中，菖蒲均处于单子叶植物中较为孤立的位置。

Infrageneric Phylogeny and Systematic Position of the Acoraceae Inferred from ITS,18S and rbcL Sequences

Inferred from the recent molecular data, Acorus was upgraded as a monotypic family, Acoraceae, although it was placed in the Araceae for a long time. The internal transcribed spacer (ITS) regions of A.gramineus,A.tatarinowii,A.calamus (with four populations sampled, representing tetraploids and hexaploids,respectively) and A.tatarinowii var. flavomarginatus were sequenced to examine the infrageneric relationship of the genus. The Acoraceae is supported as a monophyletic group.The tetraploid and hexaploid populations of A.calamus from different areas of Yunnan constituted a firm clade with high bootstrap support (100%), while A.gramineus,A.tatarinowii and A.tatarinowii var. flavomarginatus constituted another monophyletic clade with a bootstrap value of 100%.The systematic position of Acoraceae is analyzed by using the sequence data of nuclear 18S and chloroplast rbcL genes. Inferred from both phylogenetic trees of the 18S and rbcL genes, Acoraceae is in an insular position in the monocotyledons.