Novel Lessons From Ancient Plants: water transport in the earliest tracheophytes

无核维管束植物，如蕨类和马尾草，是现代植物区系中最古老的谱系之一，起源于泥盆纪，值得注意的是，这些植物在一个由针叶树和被子植物主导的世界中仍然具有竞争力。关于木本植物的生理学我们知道很多，但是如何解释无籽维管束的持续成功呢？这项拟议的研究的目标是通过生理学的镜头来研究蕨类植物和蕨类植物的盟友，特别是植物与水分的关系。高效和有弹性的水分运输是植物成功的关键，但水分运输是否在无核维管束植物的进化生理中发挥了作用尚不清楚。拟议的研究有几个目标，主要目标集中在物种的抗旱性、维管解剖、栖息地和生活史特征之间的关系，以及这些特征如何影响早期维管植物区系的进化。解剖学和生理学数据将被纳入蕨类植物水分运输的现实模型，其结果将被用于在分辨率良好的蕨类植物进化树上进行大规模采样工作。这将改善目前对特定性状促进蕨类和蕨类盟友深度多样化的方式的理解。最后，该项目将把最近开发的维管束设计模型应用于无核维管束植物，从而完成对推动所有维管束植物区系运输网络进化的选择压力的理解。更广泛的影响包括高中和本科生参与以保护为基础的红杉林下蕨类植物表现的长期研究，在当地服务不足的高中的教学模块，以及在PI的实验室指导本科生。

Seedless vascular plants such as ferns and horsetails are among the oldest lineages in the modern flora and with origins in the Devonian, it is remarkable that these plants remain competitive in a world dominated by conifers and angiosperms. Much is known about the physiology of woody plants, but what explains the continued success of the seedless vascular group? The goal of the proposed research is to examine the ferns and fern allies through the lens of physiology, specifically plant water relations. Efficient and resilient water transport is critical for plant success, but whether water transport played a role in the evolutionary physiology of seedless vascular flora remains unknown. The proposed research has several objectives with the overarching goals focusing on the relationships between species' drought resistance, vascular anatomy, habitat and life history traits, and how these features bear on the evolution of early vascular flora. Anatomical and physiological data will be incorporated into a realistic model of fern water transport, the results of which will be used to inform a large-scale sampling effort across the well-resolved evolutionary tree of ferns. This will improve present understanding of the manner in with which specific traits facilitated deep-time diversification of the ferns and fern allies. Lastly, this project will apply a recently developed model of vascular design to seedless vascular plants, and thus complete the understanding of the selection pressures driving the evolution of transport networks across all vascular flora. Broader impacts include high school and undergraduate participation in a conservation based, long-term study of fern performance in the redwood understory, teaching modules in local under-served high schools and the mentoring of undergraduate students in the PI's lab.