牵牛复合体(旋花科)的分类学研究

A Taxonomy Study on the Species Complex of Pharbitis nil(Convolvulaceae)

采用解剖镜和扫描电镜对牵牛复合体[牵牛Pharbitis nil(L.)Choisy、裂叶牵牛P.hederacea(L.)Choisy和圆叶牵牛P.purpurea(L.)Voigt]的叶形、萼片、果实和花粉形态进行了观察,同时对其叶绿体DNAtrnL-F和核基因ITS进行了分析。结果表明,牵牛、裂叶牵牛与圆叶牵牛的外部形态,在叶形、萼片的形状及毛被、果实形态上的差异明显;花粉形态的差别也较为明显;在trnL-F和ITS序列分别构建的系统树中,牵牛、裂叶牵牛和圆叶牵牛聚为一个分支,牵牛和裂叶牵牛聚为一个小分支,ITS序列系统树的支持率为70%,trnL-F序列分子树的支持率仅为63%。根据以上不同,本研究认为牵牛、裂叶牵牛和圆叶牵牛都应作为种级处理。

The morphologies of leaf, sepal, fruit and pollen of Pharbitis purpurea （ L. ） Voigt, P. nil （ L. ） Choisy and P. hederacea（ L. ）Choisy were examined under stereoscope and scanning electron microscope, and the sequences of the trnL-F region of chloroplast DNA and the nuclear ribosomal ITS region from three species were determined. The results indicated that the differences in the shape of leaf, sepal, fruit and pollen morphology are obviously different from them. In the majority-rule consensus trees from trnL-F and ITS region data, P. purpurea, P. nil and P. hederacea are included into one clade and the two latter clustered together with a support （70%） in the ITS tree ,but only 63% in the trnL-F tree. Therefore,P. purpurea （ L. ） Voigt ,P. nil（ L. ） Choisy and P. hederacea（ L. ） Choisy are respectively regarded as species.