Dissertation Research: Origin and Evolutionary Relationshipsof the Cultivated Passion Fruit (Passiflora)

小行星9701092 研究生安妮汉森，在教授的指导下。德克萨斯大学的罗伯特·詹森和劳伦斯·吉尔伯特正在研究南美洲的热带西番莲属植物。该属很大，分类学上很困难，有超过475种;西番莲亚属估计有100种，是研究的主要目标。在巴西的实地工作将增加从新热带其他地区收集的材料，补充植物标本馆的收藏。总的目标包括改进物种分类，描述可靠和稳定的字符识别，并构建一个组的基因组，从叶绿体基因组的限制性位点作图和核核糖体基因的DNA测序的新的分子数据。广泛种植的可食用西番莲（Passiflora edulis）是该亚属的成员，相关的目标是确定栽培物种的最近亲属和南美洲的可能原产地。 在美洲热带地区，西番莲属寄主植物与蝶类属的食草昆虫之间的相互作用已经做了大量的生态学研究。许多昆虫对特定的西番莲属物种具有特异性，并且一些昆虫被认为从其宿主植物中隔离有害的植物化合物（生物碱，生氰化合物）作为其自身的潜在化学防御。对这种生态相互作用的进一步研究受到西番莲属物种的系统发育缺乏的限制;目前还不知道是否密切相关的昆虫物种以密切相关的植物物种为食，或者宿主转换是否不受谱系关系的约束。该项目将改善西番莲属植物的分类，并通过提供可靠的植物系统学来促进未来的生态研究。

9701092 Jansen Graduate student Anne Hansen, under the direction of Profs. Robert Jansen and Lawrence Gilbert at the University of Texas, is studying plants of the tropical passion flower genus, Passiflora, in South America. The genus is large and taxonomically difficult, with over 475 species; the subgenus Passiflora with an estimated 100 species is the main target for study. Field work in Brazil will augment materials collected from other regions of the neotropics, complementing herbarium holdings. The general goals include improved species classification, with description of reliable and stable characters for identification, and the construction of a phylogeny for the group, from new molecular data derived from restriction site mapping of the chloroplast genome and from DNA sequencing of nuclear ribosomal genes. The widely cultivated edible passion fruit, Passiflora edulis, is a member of this subgenus, and a related goal is determination of the closest relatives of the cultivated species and the likely area of origin in South America. Considerable ecological work has been done on the interactions between Passiflora host plants and herbivorous insects of the butterfly genus Heliconius, in the American tropics. Many insects are specific to particular Passiflora species, and some are thought to sequester noxious plant compounds from their host plants (alkaloids, cyanogenic compounds) as potential chemical defenses of their own. Further research on this ecological interaction is limited by the lack of a phylogeny of the Passiflora species; it is not known whether closely related insect species feed on closely related plant species, or whether host switching is unconstrained by genealogical relationship. The project will improve the taxonomy of Passiflora species, and facilitate future ecological research by providing a reliable phylogeny for the plants.