小叶鸢尾兰及其近缘类群的物种划分研究

The delimitation of many difficult biological species and the understanding of species concept have been a major problem in taxonomy. Our previous research indicated that Oberonia japonica (Maxim.) Makino and its allies are monophyletic with a complex evolution history, while genetic divergence as well as morphological differentiation was little, and species boundaries were ambiguous. They are ideal materials for the study of species delimitation. In this study, the species delimitation of O. japonica and its allies will be examined by integrative methods. Based on field exploration and integrated with population investigations and statistics methods, the morphological variation will be assessed between inter- and intra- species. The whole plastid genomes and nuclear ribosomal DNA region will be retrieved through genome skimming approach. The phylogeny of these taxa will be reconstructed and species delimitation will be analyzed. All populations examined in the field and records from vouchers were used for niche modeling and comparisons. The niche divergence between various species will be examined by using Maxent. On the basis of different sources of data from morphometric statistics, genetic differentiation and ecological niche modeling, we expect to make a relatively objective, operational and unbiased species delimitation system for O. japonica and its allies and that these methods can also be applied to other taxa with serious taxonomic problems. This research will also shed light on the species concepts.

众多疑难生物类群的物种划分与界定以及对物种概念的理解一直以来都是分类学研究中的难题。前期的研究工作表明,小叶鸢尾兰及其近缘类群为单系，具有复杂的进化历史，形态上和遗传上种间差异均较小，种间界限模糊，是开展物种划分研究的理想类群。本研究拟在广泛野外调查的基础上，将居群概念和统计学方法应用于形态特征分析，明确种内和种间形态差异，评估各形态性状的分类学价值；基于基因组浅层测序的数据，揭示小叶鸢尾兰及其近缘类群的遗传差异，推测物种划分的合理性；利用野外采集和标本信息，进行生态位分化检测。最终结合形态、分子和生态学等方面的证据，澄清小叶鸢尾兰及其近缘类群物种划分与界定问题，为众多疑难植物类群的物种划分研究提供新思路和新方法，为物种概念的深入理解提供参考。

众多疑难生物类群的物种划分与界定以及对物种概念的理解一直以来都是分类学研究中的难题。前期的研究工作表明，小叶鸢尾兰及其近缘类群为单系，具有复杂的进化历史，形态上和遗传上种间差异均较小，种间界限模糊，是开展物种划分研究的理想类群。本项目在居群水平上，采用综合分类方法对小叶鸢尾兰及其近缘类群开展形态性状分析、基因浅层测序数据遗传差异分析和不同时期潜在生态分布区分析。结果表明，根据形态统计上的稳定过渡变异、基因遗传上的同一谱系和生态地理上密切联系，应将勐海鸢尾兰、无齿鸢尾兰和阿里山鸢尾兰并入小叶鸢尾兰；暂仅依据形态和生态地理上的联系和间断，密苞鸢尾兰亦应并入小叶鸢尾兰，而高士佛鸢尾兰则应保留独立种的地位。正确合理地处理类似复杂近缘类群，无疑能使我们更深入理解物种概念和界定，也表明基于居群水平多方面证据的综合分析对植物近缘类群的物种划分更加科学有效。