Phylogenetics of the slipper orchids (Cypripedioideae, Orchidaceae): nuclear rDNA ITS sequences
Phylogenetics of the slipper orchids (Cypripedioideae, Orchidaceae): nuclear rDNA ITS sequences
复制标题
DOI：
10.1007/bf00985442
复制
发表时间：
1997-01-01
影响因子：
1.9
通讯作者：
Chase, MW
中科院分区：
文献类型：
--
作者：
Cox, AV;Pridgeon, AM;Chase, MW
菊科(兰科)一直是许多分类处理的主题，对5属和150-170种之间的关系有相互矛盾的解释。我们已经产生了近100种拖鞋兰科植物的核核糖体ITS核苷酸序列，并使用简约分析来研究它们之间的关系。我们的结果表明，按照目前的划分，每个属都是单系的(Mexipedium和Selenipedium由一个分类单元代表)。与rbcL数据一样，ITS序列将Mexipedium列为芦荟的姊妹植物。Paphiopedilum在组水平上的关系很大程度上与Cribb所描述的一样。然而，兜兰亚属的分类结果表明。不支持短瓣草和兜铃草；短瓣藻与亚种属同源。兜兰属。与McCook的分类方案一样，芦荟被分为三个主要支系。折叶属和叠叶属是亚科其余部分的连续姐妹群，证实了普遍认为的它们与复叶属相比表现出多形性的观点。在ITS树的背景下对核型的调查揭示了染色体数量增加的总体趋势，这可能是由着丝粒分裂引起的。这些数据也符合之前提出的生物地理学假说，即北半球分布广泛，随后由于中新世冷却而出现范围碎裂。
Cypripedioideae (Orchidaceae) have been the subject of numerous taxonomic treatments with conflicting interpretations of relationships among the five genera and the 150-170 species. We have produced nuclear ribosomal ITS nucleotide sequences for nearly 100 slipper orchid species and used parsimony analysis to investigate their relationships. Our results demonstrate that each genus, as currently circumscribed, is monophyletic (Mexipedium and Selenipedium being represented by a single taxon). Like rbcL data, ITS sequences place Mexipedium sister to Phragmipedium. Relationships at the sectional level in Paphiopedilum are largely as described by CRIBB. However, the division of Paphiopedilum into subgg. Brachypetalum and Paphiopedilum is not supported; subg. Brachypetalum is paraphyletic to subg. Paphiopedilum. Phragmipedium species are divided into the same three major clades as in the taxonomic scheme of McCooK. The plicate-leaved genera, Cypripedium and Sebenipedium, are successive sister groups to the rest of the subfamily, confirming generally held opinions that they display plesiomorphic characters compared to the conduplicate-leaved genera. A survey of karyotypes in the context of the ITS tree reveals a general trend toward increased chromosome number, probably brought about by centric fission. These data also accord with a previously suggested biogeographic hypothesis of a widespread Northern Hemisphere distribution, followed by range fragmentation due to Miocene cooling.