Molecular and Morphological Systematics of The Subtribe Oncidiinae (Orchidaceae)

Oncidiinae 亚族（兰科）的分子和形态系统学

• 批准号: 9815821
• 负责人: Norris Williams
• 金额: --
• 依托单位: University of Florida
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-02-15 至 2003-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9815821&HistoricalAwards=false
• 关键词: Molecular; Morphological; Systematics; Subtribe; Oncidiinae

9815821Williams The taxonomic classification of the orchid family, with an estimated 20,000 species or more (the largest family of flowering plants), has depended heavily upon features of the orchid flower. Many aspects of floral form in orchids appear to be adaptations to animal pollinators, to facilitate or ensure within-species transfer of pollen, and are less likely to signify close genealogical relationship than previously assumed. As data have accumulated on other morphological and anatomical features, these cases of suspected convergence or parallelism in floral form have become more numerous and troublesome for a stable classification of the group. Modern DNA sequencing technologies now provide sources of independent genetic data for use in assessing phylogenetic or genealogical relationships among species, genera, and tribes within the family. Dr. Norris Williams of the University of Florida is studying the neotropical subtribe Oncidiinae for DNA sequences from nuclear ribosomal genes and from chloroplast gene regions, to amass data bearing on mutational differences among this large array of orchids. The group comprises about 80 genera and 1500 species, and sampling will cover all the genera and ca. 500 of the species, with particular attention to the large genera Oncidium, Odontoglossum, and Cyrtochilum. The subtribe Oncidiinae includes orchids with a wide spectrum of pollination relationships, including pollen transfer by male euglossine bees (collecting floral fragrance compounds), by other species of bees and insects collecting nectar or pollen, and by hummingbirds. Controversial cases of pollination by insects where no apparent food reward is discernible have been described under the rubric of pseudocopulation. In addition, the subtribe includes numerous small orchids that are "twig epiphytes," growing literally on the ends of twigs in neotropical rainforests, and including some of the smallest known orchid plants. A stable classification of these and other orchids, based on substantial gene sequence data from both nuclear and plastid sources, will establish a solid framework for the study of evolution of pollination relationships and of growth form and function in tropical forests.

9815821威廉姆斯兰科的分类学分类，估计有20，000种或更多（开花植物中最大的家族），在很大程度上取决于兰花的特征。兰花花形的许多方面似乎是对动物传粉者的适应，以促进或确保花粉的种内转移，并且不太可能比以前假设的那样表示密切的系谱关系。随着其他形态学和解剖学特征的数据积累，这些疑似花型会聚或平行的病例变得越来越多，对该组的稳定分类造成了麻烦。现代DNA测序技术现在提供了独立的遗传数据来源，用于评估科内种、属和部落之间的系统发育或谱系关系。佛罗里达大学的诺里斯威廉姆斯博士正在研究新热带亚族Oncidiinae的核核糖体基因和叶绿体基因区域的DNA序列，以收集与这一大系列兰花之间的突变差异有关的数据。该类群包括约80属1500种，采样将涵盖所有属和ca。500个物种，特别关注文心兰属、齿舌兰属和仙草属。文心兰亚族包括具有广泛授粉关系的兰花，包括雄性真舌蜂（收集花香化合物）、其他种类的蜜蜂和昆虫收集花蜜或花粉以及蜂鸟的花粉转移。有争议的情况下，授粉的昆虫没有明显的食物奖励是可辨别的已被描述下的标题下的假交配。此外，该亚族还包括许多小兰花，它们是“树枝附生植物”，生长在新热带雨林的树枝末端，包括一些已知的最小的兰花植物。基于来自核和质体来源的大量基因序列数据，对这些和其他兰花进行稳定的分类，将为研究热带森林中授粉关系和生长形式和功能的进化建立一个坚实的框架。