Systematics, Phylogeny, and Pollination System Evolution in Callitrichaceae

9307038菲尔布里克水下授粉(水生)是开花植物中最神秘的授粉系统之一。水生植物需要放弃或修改一组与干燥的空中开花条件密切相关的特征，代表了花生物学的一种转变，对花和花粉的形态产生了深远的影响。实现润湿性(水下释放和捕获花粉)所需的机械和生物化学改造带来了重大的适应性障碍，这在从一种空中授粉系统向另一种授粉系统的进化转变过程中没有遇到。菲尔布里克博士项目的目标是利用马蹄莲属植物作为实验系统，探索有关水生授粉进化的问题。Callitriche是进行这些研究的最合适的组，因为它是被子植物中唯一同时包括空中和水下授粉系统的属。利用形态和新的DNA特征进行的系统发育分析将提供对该属各物种花和花粉特征变化方向的理解，从而有助于确定适应水下授粉的变化模式。水下授粉是在某些开花植物群体中发现的比较奇怪的适应方式之一。菲尔布里克博士正在一个明确的系统发育框架中研究这一现象，该框架包括水下授粉和空中授粉系统。花和花粉特征的变化方向可以确定，反过来，这一知识将允许分析负责新花结构的细胞和生化机制。

9307038 Philbrick Underwater pollination (hydrophily) is one of the most enigmatic pollination systems in flowering plants. Hydrophily requires the abandonment or modification of a suite of characters intimately tied to the dry, aerial flowering condition, and represents a shift in floral biology with profound consequences for flower and pollen morphology. The mechanical and biochemical modifications entailed in achieving wettability (underwater release and capture of pollen) raise significant adaptive obstacles not encountered during evolutionary shifts from one aerial pollination system to another. The goals of Dr. Philbrick's project are to probe questions concerning the evolution of water pollination using the genus Callitriche as an experimental system. Callitriche is the most appropriate group to conduct these studies because it is the only genus of angiosperms that includes both aerial and underwater pollination systems. Phylogenetic analysis using morphological and new DNA characters will provide an understanding of the direction of change in floral and pollen features across the species in the genus, and thereby help determine models of change in adaptation to underwater pollination. %%% Underwater pollination is one of the more bizarre adaptations found in certain groups of flowering plants. Dr. Philbrick is studying this phenomenon in an explicit phylogenetic framework for the ca. 50 species of the genus Callitriche that includes both underwater and aerial pollination systems. The direction of change in floral and pollen features can be determined, and in turn this knowledge will allow analysis of cellular and biochemical mechanisms responsible for new floral structure.