Dissertation Research: Systematics of the Genus Dischidia (Marsdenieae, Asclepiadaceae) and of the Tribe Marsdenieae

论文研究：Dischidia属（Marsdenieae、Asclepiadaceae）和Marsdenieae部落的系统学

• 批准号: 9902073
• 负责人: Melissa Luckow
• 金额: --
• 依托单位: Cornell Univ - State: AWDS MADE PRIOR MAY 2010
• 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: 1999-05-15 至 2001-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9902073&HistoricalAwards=false
• 关键词: Dissertation; Research; Systematics; Genus; Dischidia

9902073Luckow and LivschultzDischidia (Asclepiadaceae, milkweed family) is a genus of succulent, epiphytic vines native to Southeast Asia. It is closely related to the ornamental plant Hoya (porcelain flower). The best known species, Dischidia major, has pitcher leaves that are used as nesting sites by arboreal ants. The ants accumulate organic debris inside the pitcher leaves and the plant grows adventitious roots into the leaf interior and derives nutrients from the accumulated debris. Many of the other 80 or so species of Dischidia also occur in arboreal ant nests, and they have a variety of structures that may function in ant/plant interactions. Some species have shell-shaped leaves that are held tightly against the bark of the host tree; like the pitcher leaves, these may also function as ant houses (domatia). Other species have normal leaves, but have oil-rich structures on the seeds (elaiosomes) that are attractive to ants and may facilitate seed dispersal to ant nests. There are also some species that do not occur in ant nests and do not have any structures that are considered to function in ant/plant interactions. Graduate student Tatyana Livschultz, under the direction of Dr. Melissa Luckow of Cornell University, is conducting research on the evolutionary relationships of Dischidia to understand the evolution of structures that function in ant interactions in this genus. Information from plant morphology and from nuclear and chloroplast gene sequences is being used to construct an evolutionary (phylogenetic) tree and retrace the sequence of origin of structures that facilitate ant interactions. This phylogenetic tree will also be used to revise the infra-generic classification of Dischidia and to prepare a detailed monograph of one section of this genus. Additional sampling of putative relatives of Dischidia will help in reconstructing evolutionary relationships in the tribe Marsdenieae, which comprises ca. 25 genera and about 570 species (25% of the species in the milkweed family). This analysis will test the hypothesized sister-group relationship between Dischidia and Hoya, examine relationships among genera in the tribe, and test the circumscription of the tribe. The research will provide the basis for a revised classification of these under-studied tropical groups. This classification, a summary of all available information on these plants, will be available to others interested in their evolution, ecology, conservation, cultivation, and medicinal properties.

9902073Luckow 和 LivschultzDischidia（萝藦科，马利筋科）是一种多汁、附生藤本植物，原产于东南亚。它与观赏植物Hoya（瓷花）密切相关。最著名的物种是Dischidia Major，其捕虫笼叶被树栖蚂蚁用作筑巢地。蚂蚁在猪笼草叶内积累有机残骸，植物在叶子内部长出不定根，并从积累的残骸中获取养分。其他 80 多个 Dischidia 物种中的许多种也出现在树栖蚁巢中，它们具有多种可能在蚂蚁/植物相互作用中发挥作用的结构。有些物种的叶子呈贝壳状，紧紧地贴在寄主树的树皮上。像猪笼草叶一样，它们也可以用作蚂蚁屋（domatia）。其他物种有正常的叶子，但种子上有富含油的结构（油质体），这对蚂蚁有吸引力，并可能促进种子传播到蚂蚁巢穴。还有一些物种并不存在于蚂蚁巢中，并且不具有任何被认为在蚂蚁/植物相互作用中起作用的结构。 研究生 Tatyana Livschultz 在康奈尔大学 Melissa Luckow 博士的指导下，正在对 Dischidia 的进化关系进行研究，以了解在该属蚂蚁相互作用中起作用的结构的进化。来自植物形态以及核和叶绿体基因序列的信息被用来构建进化（系统发育）树，并追溯促进蚂蚁相互作用的结构起源序列。该系统发育树还将用于修订 Dischidia 的下属分类，并准备该属的一个部分的详细专着。对 Dischidia 的推定亲属进行额外采样将有助于重建 Marsdeniee 部落的进化关系，该部落由约 100 名成员组成。 25属，约570种（占马利筋科物种的25%）。该分析将测试 Dischidia 和 Hoya 之间假设的姐妹群体关系，检查部落中属之间的关系，并测试部落的范围。该研究将为这些未被充分研究的热带群体的修订分类提供基础。该分类总结了有关这些植物的所有可用信息，可供对其进化、生态、保护、栽培和药用特性感兴趣的其他人使用。