Dissertation Research: Phylogenetic Relationships and Pollination of Acridocarpus and Other Old World Malpighiaceae.

0073299Baum，Donoghue和Davis Malpighiaceae是一个开花植物家族，是新旧世界热带森林和稀树草原的重要组成部分。 新世界金雀花科由专门的采油蜂（花蜂科雌性）授粉，尽管果实形态和习性存在巨大差异，但其花形态高度保守。 这些采油蜜蜂在旧大陆是不存在的。 一些旧大陆的分支，如Acridocarpus，被认为是来自新大陆的血统，他们表现出与油蜂授粉和“嗡嗡声”授粉相关的特征的组合。 这些群体提供了一个机会来研究失去专门的传粉者的后果。 研究生Charles Davis在大卫鲍姆博士和迈克尔多诺霍博士的指导下进行了这项研究，目的是（1）利用叶绿体和核DNA序列推断Malpighiaceae内的系统发育关系，（2）推断Acridocarpus物种的系统发育或谱系，以检查与传粉者转移相关的花形态进化模式，（3）记录非洲生境中的Acridocarpus授粉。初步的分子数据表明，旧大陆属的Malpighiaceae属于几个独立的谱系，这表明蜂音授粉相关的形态已经独立进化了不止一次。 然而，冲突的几个领域仍然没有得到很好的解决。 此外，需要将几个额外的旧世界血统添加到现有的数据集。 使用核糖体DNA序列分析的Acridocarpus揭示了两个主要分支，一个包括马达加斯加和新喀里多尼亚特有的物种，另一个包括分布在非洲各地的物种。 马达加斯加和新喀里多尼亚的物种似乎完全没有油腺，但在一些非洲物种中出现。 在非洲的野外工作表明，Acridocarpus的物种是由大型木蜂授粉的，这些蜜蜂嗡嗡作响花药，花腺体产生糖而不是油。通过附加的叶绿体DNA序列，沿着核光敏色素基因序列，解决金雀花科植物的亲缘关系，将阐明旧大陆物种的起源和亲缘关系。 进一步的系统发育研究将允许评估具有相似形态的旧大陆物种是否独立进化，以及这种花的进化是否与石油采集传粉者的丧失有关。 本研究将有助于阐明传粉系统转换后形态变化的模式和机制。

0073299Baum, Donoghue, and Davis Malpighiaceae are a family of flowering plants that are an important element of forests and savannas in the Old and New World tropics. New World Malpighiaceae are pollinated by specialized oil-collecting bees (anthophorid females) and exhibit a highly conserved floral morphology despite tremendous diversity in fruit morphology and habit. These oil-collecting bees are absent from the Old World. Some Old World clades, like Acridocarpus, are presumed to be derived from New World lineages and they exhibit a combination of features associated with oil-bee pollination and with "buzz" pollination. These groups provide an opportunity to examine the consequences of the loss of specialized pollinators. The goals of this study by graduate student Charles Davis, under the direction of Drs. David Baum and Michael Donoghue, are (1) to infer the phylogenetic relationships within Malpighiaceae using chloroplast and nuclear DNA sequences, (2) to infer the phylogeny or genealogy of Acridocarpus species in order to examine patterns of floral morphological evolution associated with pollinator shifts, and (3) to document the pollination of Acridocarpus in African habitats. Preliminary molecular data indicate that Old World genera of Malpighiaceae belong to several separate lineages, suggesting that morphologies associated with buzz pollination have evolved more than once independently. However, several areas of the phylogeny remain poorly resolved. Furthermore, several additional Old World lineages need to be added to existing datasets. Analyses of Acridocarpus using ribosomal DNA sequences reveal two major clades, one including species endemic to Madagascar and New Caledonia and the other consisting of species distributed across Africa. Oil glands appear to be entirely absent in species from Madagascar and New Caledonia, but appear in some African species. Fieldwork in Africa indicates that species of Acridocarpus are pollinated by large xylocopine bees that buzz the anthers, and the floral glands produce sugars rather than oils. Resolving the phylogeny of Malpighiaceae with additional chloroplast DNA sequences, along with sequences of a nuclear phytochrome gene, will clarify the origin and relationships of the Old World species. Further phylogenetic work will allow an evaluation of whether Old World species with similar morphologies have evolved independently, and whether such floral evolution is associated with the loss of oil-collecting pollinators. This study will shed light on the patterns and mechanisms of morphological change following a shift in pollination system.