Dissertation Research: Systematics and Flower Development in the Milkweed Tribe Gonolobeae (Asclepiadaceae)

在华盛顿大学的Barbara Schaal博士和密苏里州植物园的Peter Raven博士的指导下，研究生托马斯普林齐正在研究新热带乳草藤蔓（萝摩科中的Gonolobeae部落）的进化关系和花形态。马利筋花是高度专业化的结果复杂的融合花的部分和独特的冠结构的存在。在德克萨斯州和墨西哥南部的实地工作期间，Prinzie先生收集了大约60种鲜花，使他能够使用标准解剖切片技术和扫描电子显微镜详细研究它们的结构。通过收集许多发展阶段的信息，还可以追踪各种日冕结构的起源，其多样性在过去曾使分类学家感到困惑。这项研究的第二个组成部分是根据两个独立的核基因和叶绿体基因的DNA序列数据重建这个乳草部落的进化历史。由此产生的系统发育信息将补充其他研究正在进行更高的分类水平，在这个和密切相关的家庭。通过在一个独立建立的植物发生学的框架内研究Gonolobeae花的结构和发育，将有可能澄清导致其巨大多样性的进化修饰，并说明发育变化作为多样化机制的作用。

Schaal, Raven, and Prinzie Graduate student Thomas Prinzie, under the direction of Dr. Barbara Schaal at Washington University and Dr. Peter Raven at the Missouri Botanical Garden, is studying the evolutionary relationships and flower morphology of a neotropical group of milkweed vines (tribe Gonolobeae in the family Asclepiadaceae). Milkweed flowers are highly specialized as a result of complex fusion between floral parts and the presence of unique corona structures. During field work in Texas and Southern Mexico, Mr. Prinzie has collected fresh flowers of some 60 species, allowing him to study their structure in great detail using both standard anatomical sectioning techniques and scanning electron microscopy. By collecting information at many stages of development, it will also be possible to trace the origin of the various corona structures, whose diversity has confused taxonomists in the past. A second component of the research consists in reconstructing the evolutionary history of this tribe of milkweeds, on the basis of DNA sequence data from two separate nuclear and chloroplast genes. The resulting phylogenetic information will complement other studies being performed at higher taxonomic levels in this and closely related families. By studying the structure and development of Gonolobeae flowers in the framework of an independently established phylogeny, it will be possible to clarify the evolutionary modifications that gave rise to their great diversity, and to illustrate the role of developmental changes as a mechanism of diversification.