RUI: Collaborative Research: The Cenozoic radiation of eupolypod ferns: did selection for drought tolerance drive the evolutionary physiology of sporophytes and gametophytes?

无籽维管植物（如蕨类植物）是继开花植物之后第二个最多样化的植物谱系，但鉴于其两阶段生命周期和明显的耐旱性，其持续成功的基础尚未完全了解。 最近的研究表明，蕨类植物的叶状体（营养世代）和蕨类植物的配子体（有性世代）都进化出了许多策略来科普严重的干旱胁迫并从中恢复过来。本研究调查了蕨类植物生命周期的两个阶段的水关系，以检验这一假设，即通常与耐旱性相关的性状的演变促进了蕨类植物从大部分潮湿的陆地栖息地向干燥，阳光充足的树冠栖息地的扩张。这项研究将集中在两个最近的蕨类植物谱系的耐旱特性，这代表了热带蕨类植物物种多样性的大部分。将在田间和实验室中对选定物种的生理、形态和解剖属性进行检查。这项基础研究不仅将扩大对生物多样性形成过程的了解，而且还可能确定新的植物性状，有助于开发更耐旱的农业物种。学生将在墨西哥和哥斯达黎加获得国际研究经验，学生/教师交流将促进研究合作。面向公众的外联活动将与拯救红杉联盟和南部麦迪逊遗产信托基金的非营利合作者联合收割机相结合，以说明蕨类植物和其他非维管植物在自然植物群落生态学中的重要作用。为了确定干旱胁迫是否会对蕨类孢子体和配子体产生强大的趋同选择压力，本研究将研究蕨类植物中许多物种的配子体的脱水耐受性。蕨科是一个超多样性的家庭蕨类植物的祖先的Eupolypods，从这项研究的结果将补充现有的数据集记录耐旱性的蕨科孢子体。第二组研究将检查附生和陆生真多足类孢子体的耐旱性。实验将通过干旱引起的空气进入、叶片膨压损失点来测试对水力破坏的抵抗力，并将这些数据与许多解剖学和形态学性状联系起来。最后，将进行补充研究，研究这一组配子体的干燥耐受性。结果将在系统发育框架中进行分析，该框架将明确测试孢子体和配子体中的相关性状进化。

Seed-free vascular plants such as ferns are the second most diverse plant lineage after the flowering plants, yet given their two-stage lifecycle and apparent intolerance of drought, the bases of their continued success are not completely understood. Recent studies have shown that both fern fronds (the vegetative generation) and fern gametophytes (the sexual generation) have evolved numerous strategies to cope with and recover from severe drought stress. This research investigates the water relations of both stages of the fern lifecycle to test the hypothesis that the evolution of traits typically related to drought tolerance promoted the expansion of ferns from largely moist, terrestrial habitats to drier, sunnier canopy habitats. The research will focus on drought tolerant traits of two recent fern lineages, which represent the bulk of tropical fern species diversity. Physiological, morphological and anatomical attributes will be examined across select species in the field and in the laboratory. This basic research will not only expand knowledge of the processes that shape biological diversity, but also potentially identify novel plant traits that could assist with the development of more drought resistant agricultural species. Students will receive international research experiences in Mexico and Costa Rica, and student/instructor exchanges will promote research collaboration. Outreach activities to the public will combine with non-profit collaborators at the Save the Redwood League and the Southern Madison Heritage Trust to illustrate the important role of ferns and other non-vascular plants in the ecology of natural plant communities. In order to determine whether drought stress exerts strong, convergent selection pressure on fern sporophytes and gametophytes, this research will examine the desiccation tolerance of gametophytes from numerous species in the Pteridaceae. The Pteridaceae are a hyper-diverse family of ferns that are ancestral to the Eupolypods, and the results from this study will complement an existing data set documenting drought tolerance in the Pteridaceae sporophytes. A second set of studies will examine the drought tolerance of epiphytic and terrestrial Eupolypod sporophytes. Experiments will test resistance to hydraulic failure by drought-induced air entry, leaf turgor loss points, and relate these data to numerous anatomical and morphological traits. Lastly, complementary studies looking at the desiccation tolerance of gametopytes in this group will be conducted. The results will be analyzed in a phylogenetic framework, which will explicitly test for correlated trait evolution in both sporophytes and gametophytes.