Using seed-free plants to link diversity in stomatal function with ecological strategy

植物通过叶子上被称为气孔的微小孔从大气中获取二氧化碳。当气孔打开以获得二氧化碳时，水通过蒸发而流失到大气中。由于植物生长所需的碳增益和可能导致脱水的水分损失之间的权衡，有许多来自环境和植物的信号触发气孔的打开和关闭。该奖项旨在研究不同蕨类植物对环境条件的气孔响应是否存在差异，以及这种差异是否与生态策略和栖息地偏好有关。本项目将重点研究蕨类和石松类植物，这是一种气孔行为相对简单的古老植物类群，气孔功能的变化可能对植物的生长和生存产生较大影响。研究结果将有助于了解气孔对环境的响应是如何演变的，以及如何在农业物种中控制气孔以提高植物的水分利用和生产力。该项目还将向公众和学生介绍植物的动态特性，以帮助提高对这些静态景观特征的反应和活力的认识，并为本科生提供研究培训。本项目将利用比较研究的方法探讨无种子植物气孔功能自然多样性的三个关键假设。第一种假说认为，通过水生生长习惯的进化或营养物质的干燥耐受性，消除水分限制对生存的威胁，推动了新的气孔功能的进化，特别是气孔关闭的调节。第二种观点认为，独特的叶片水力特性的进化促进了新的气孔调节机制的进化。最后，本项目将测试在一个生态多样化的蕨类植物科中，气孔调节、叶片水力性状和生态策略是否存在协调进化。该项目将利用大量现存的蕨类和石松类植物，并通过野外实验来验证这些假设，主要是通过比较研究密切相关但生态不同的物种之间的气孔和植物水力生理。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Plants obtain carbon dioxide from the atmosphere through microscopic pores on the leaves called stomata. When stomata open to obtain carbon dioxide, water is lost to the atmosphere by evaporation. Due to the tradeoff between carbon gain used for plant growth and water loss that might lead to dehydration, there are many signals from the environment and plant that trigger stomatal opening and closing. This award aims to investigate whether there is variation across fern species in the responses of stomata to environmental conditions, and whether this variation can be linked to ecological strategies and habitat preference. This project will focus on ferns and lycophytes, ancient groups of plants that have comparatively simple stomatal behavior, in which variation in stomatal function is likely to have a large impact on plant growth and survival. The results will increase understanding of how stomatal responses to the environment evolved and how they could be manipulated in agricultural species to improve plant water use and productivity. This project will also inform the public and students on the dynamic nature of plants, to help raise awareness of how responsive and alive these otherwise static features of the landscape are, as well as provide research training to undergraduate students. This project will investigate three key hypotheses using comparative studies to characterize the natural diversity of stomatal function found in seed-free plants. The first hypothesis proposes that eliminating the threat of water limitation on survival through the evolution of an aquatic growth habit or vegetative desiccation-tolerance, drives the evolution of novel stomatal function, particularly in the regulation of stomatal closure. The second proposes that the evolution of unique leaf hydraulic properties facilitates the evolution of novel stomatal regulation. Finally, this project will test whether there is coordinated evolution in stomatal regulation, leaf hydraulic traits and ecological strategy across an ecological diverse fern family. This project will draw upon a large living collection of diverse fern and lycophyte species and field experiments to address these hypotheses, primarily through comparative studies of stomatal and plant hydraulic physiology between closely related yet ecologically dissimilar species.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.