Dissertation Research: Molecular and Anatomical Systematics of Leafless Vandeae (Orchidaceae)

兰花是最大的植物家族之一，约有20，000种。 它们代表了一个极其多样化的生物群体，分布于世界各地，除南极洲外的每一个大陆都有。 大部落Vandeae占整个家庭的10%。 它拥有几个非常特化的成员，这些成员在进化上已经退化到无叶和几乎无茎的状态。 这些植物完全依靠它们的绿色根来制造食物。 本研究的主要目的是利用DNA分子证据以及根的宏观和微观结构证据，为这些无叶的Vandeae建立系统发育假说。随着最近大量的分子数据，植物类群的进化关系正在重新建立和重新界定。 令人惊讶的是，Vandeae是兰科中的一个重要类群，基本上没有被分子分类学家所触及。 这项研究将提供一个额外的字符集，它可以用来推导进化关系的假设。 更重要的是，关于最极端的附生模式之一的进化问题将得到回答。

Orchids comprise one of the largest plant families with approximately 20,000 described species. They represent an extremely diverse group of organisms with a worldwide distribution, occurring on every continent except Antarctica. The large tribe Vandeae makes up 10% of the entire family. It possesses several very specialized members that have been evolutionarily reduced to a leafless and often almost stemless state. These plants depend entirely on their green roots for food manufacture. The primary focus of this study is to develop a phylogenetic hypothesis for these leafless Vandeae using molecular evidence from DNA as well as evidence from macro- and microscopic root structure.With the recent spate of molecular data, evolutionary relationships of plant groups are being reestablished and recircumscribed. Surprisingly, Vandeae, a significant group within the orchid family, has been essentially untouched by molecular taxonomists. This study will provide an additional set of characters, which can be used to derive hypotheses of evolutionary relationships. More importantly, questions concerning the evolution of one of the most extreme modes of epiphytism will be answered.