Dissertation Research: Systematics and Floral Morphology Evolution in the Genus Piper (Piperaceae)

9972600Manos和Jaramillo研究生Alejandra Jaramillo在杜克大学Paul Manos博士的指导下，正在研究胡椒大属（黑色和白色胡椒属，约有1200种）的分类学分类和这个热带类群中几个物种的花形态发展。在世界各地的热带森林中，风笛属植物以灌木、藤本植物和草本植物的形式存在。尽管单个Piper花很小，但该物种在单性和双性形式中表现出广泛的多样性，包括各种类型的完美花，其雄蕊的数量和位置关系不同。然而，花的变异模式还没有被独立测试作为系统发育（或谱系）关系的可靠指标。本项目将强调细胞核和叶绿体基因的DNA测序作为证据来源，构建约130个亚属代表物种的框架系统发育和已知属的地理多样性，以进一步研究花形态的个体发育阶段。个体发生的改变，如雌雄异株和雄蕊极度减少，将被映射到系统发育中，以测试花的创新和整个属的多样化之间的关系。系统发育分析还将改进这一大属的亚属和剖面分类，并有助于改进种水平的划分。对Piper的进化史的更好理解提供了一个机会，以确定“原始”dico的最大属多样化的关键花卉创新。

9972600Manos and Jaramillo Graduate student Alejandra Jaramillo, under the direction of Dr. Paul Manos at Duke University, is studying the taxonomic classification of the large genus Piper (the genus of black and white pepper, with ca. 1200 species) and the development of floral morphology in several species of this tropical group. Piper species occur as shrubs, lianas, and herbs in the understory and canopy of tropical forests worldwide. Although individual Piper flowers are minute, the species express a wide range of diversity in unisexual and bisexual forms, including various types of perfect flowers that differ in the number and positional relationships of their stamens. However, patterns of floral variation have not been independently tested as reliable indicators of phylogenetic (or genealogical) relationship. This project will emphasize the DNA sequencing of both nuclear and chloroplast genes as sources of evidence to construct a framework phylogeny for ca. 130 species representative of the subgenera and geographical diversity known for the genus, in order further to study ontogenetic (developmental) stages in flower morphology. Ontogenetic modifications, such as dioecy and extreme stamen reduction, will be mapped onto phylogenies to test the association between floral innovation and diversification across the genus. Phylogenetic analysis will also improve the subgeneric and sectional classification of this large genus, and help advance improved species-level delimitation. An improved understanding of the evolutionary history of Piper provides an opportunity to identify key floral innovations in the diversification of the largest genus of "primitive" dicots.