Collaborative Research: Using Phylogeny to Investigate the History of Morphological Evolution in Heterosporous Ferns

合作研究：利用系统发育学研究异孢蕨类植物形态进化的历史

• 批准号: 0089908
• 负责人: Richard Lupia
• 金额: $ 9.96万
• 依托单位: University of Oklahoma Norman Campus
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-08-01 至 2006-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0089908&HistoricalAwards=false
• 关键词: Collaborative; Research; Using; Phylogeny; Investigate

Throughout the evolutionary history of land plants there have been repeated invasions of aquatic environments by terrestrial plants from distantly related lineages. In order to survive these very different physical conditions, these plants have been selected to modify their vegetative, reproductive, and dispersal systems. Few living ferns are aquatic; most are terrestrial and homosporous (bearing a single spore type). The exceptions are the heterosporous ferns, the semi-aquatic Marsileaceae and aquatic Salviniaceae, which belong to a single evolutionary lineage. The five extant genera of heterosporous ferns have been little studied, but the fossil record of their ornamented spores is relatively good for these ferns, showing a Cretaceous diversification contemporary with the rise of the flowering plants. In a collaboration between fern specialists Kathleen Pryer and Harald Schneider at Duke University and paleobotanist Richard Lupia at University of Oklahoma, the researchers will integrate morphological and molecular studies on the rates and sequences of evolution of all the known species of water ferns, to understand the history of adaptations to the aquatic environment. A comprehensive phylogeny of all the species will be constructed from DNA sequence comparisons, integrated with morphological studies. Spore ultrastructural characters will be studied with the electron microscope to investigate developmental features of spore wall construction and ornamentation, in order to interpret and integrate fossil spores known for the group. Numerous morphological trends have been proposed on the basis of the relative order of appearance in the fossil record, and the explicit phylogeny constructed for the group will allow testing of these ideas about character evolution in water ferns. The investigators bring complementary skills to the study from fields of morphology, DNA sequence analysis, phylogenetic methods, paleobotany, and quantitative analyses. The study provides an ideal opportunity to test hypotheses about the adaptive radiation of the modern fern flora from the Cretaceous to the Recent, the colonization of aquatic habitats, and genetic models of developmental change.

在陆生植物的进化史中，有来自远亲谱系的陆生植物反复入侵水生环境。为了在这些非常不同的物理条件下生存，这些植物被选择来修改它们的营养，生殖和传播系统。很少有现存的蕨类植物是水生的;大多数是陆生的，孢子类型相同（带有单孢子类型）。例外的是异孢蕨类植物，半水生的Marsileaceae和水生的Salviniaceae，它们属于一个单一的进化谱系。现存的五个异孢蕨类属的研究很少，但它们的孢子化石记录相对较好，显示了白垩纪的多样性，与开花植物的兴起同步。在杜克大学的蕨类植物专家Kathleen Pryer和Harald Schneider与俄克拉荷马州大学的古植物学家Richard Lupia之间的合作中，研究人员将整合对所有已知水生蕨类植物物种进化速度和序列的形态和分子研究，以了解适应水生环境的历史。一个全面的系统发育的所有物种将构建从DNA序列比较，结合形态学研究。孢子超微结构特征将用电子显微镜研究，以调查孢子壁构建和发育特征，以解释和整合已知的化石孢子。根据化石记录中出现的相对顺序，已经提出了许多形态学趋势，并且为该组构建的明确的系统发育将允许测试这些关于水生蕨类植物特征进化的想法。研究人员从形态学、DNA序列分析、系统发育方法、古植物学和定量分析等领域为这项研究带来了补充技能。这项研究提供了一个理想的机会，以测试假设的适应性辐射的现代蕨类植物植物群从白垩纪到最近，水生栖息地的殖民化，和遗传模型的发展变化。