Dissertation Research: Selection, niche breadth and plant mating system evolution: Are wider niche breadths of selfing species shaped by water limitation?

本研究将探讨植物交配系统的类型是否对植物在逆境中的生存有影响。植物交配系统，从自花授粉到异花授粉，花粉必须在不同的植物之间移动才能受精，可能对野生植物物种的生存环境产生重大影响。自花授粉的物种预计将比异交物种更好地殖民新的地区，因为它们不需要授粉者或配偶的存在。这项研究将测试的假设，自花授粉的物种也有生理优势，使他们能够超越异交物种在压力，水分有限的环境。研究人员将收集和分析各种生理数据，如生长速度和相对健康，从多个，密切相关的对自交和异交Collinsia植物。研究结果将揭示影响植物交配系统进化的重要因素。此外，该项目将涉及指导本科生，包括来自科学领域代表性不足的群体的个人。计划开展的外联活动包括为小学生开展教育活动。最近的研究结果支持理论模型，认为自交可能是一个生态位多样化的特点，因为它允许殖民新的栖息地缺乏传粉者或配偶。建议的研究建立在以前的结果交配系统和生态位宽度测试是否自交物种相对于异交种的生理表现有助于观察到的重复模式的生态位宽度分化的姐妹种对在属Collinsia。为了验证自交系更好地适应水分有限环境的假设，研究人员将通过比较自交/异交姐妹种对的植物标本叶片样本中稳定同位素13 C：12 C的比例与国际标准中的13 C：12 C来衡量干旱胁迫。他们还将在温室中在高水和限水处理中种植三个自交/异交姐妹物种对，并测量生理，生长和繁殖性状反应。研究结果将对我们理解生态位宽度的演化和维持产生重要影响。

This project will investigate whether the type of plant mating system contributes to whether a plant can survive in stressful habitats. Plant mating systems, which range from self-pollinating to outcross-pollinating, where pollen has to be moved among different plants for fertilization to happen, can have significant effects on where wild plant species live. Self-pollinating species are expected to be better than outcrossing species at colonizing new areas because they do not require the presence of either pollinators or mates. This study will test the hypothesis that self-pollinating species also have physiological advantages that allow them to outperform outcrossing species in stressful, water-limited environments. The researchers will collect and analyze a variety of physiological data, such as growth rate and relative fitness, from multiple, closely-related pairs of selfing and outcrossing Collinsia plants. Results of this work will reveal important factors influencing the evolution of plant mating systems. In addition, the project will involve mentoring of undergraduate students, including individuals from groups that are underrepresented in the sciences. Planned outreach activities include the development of educational activities for elementary school children. Recent findings support theoretical models that suggest selfing may be a niche diversifying trait because it allows colonization of new habitats lacking pollinators or mates. The proposed research builds on previous results on mating systems and niche breadth by testing whether the physiological performance of selfing species relative to outcrossers contribute to the observed repeated patterns of niche breadth differentiation between sister species pairs in the genus Collinsia. To test the hypothesis that selfers are better adapted to water-limited environments, the investigators will measure drought stress by comparing the ratio of stable isotopes 13C:12C in herbarium leaf samples of selfing/outcrossing sister species pairs relative to the 13C:12C in the international standard. They will also grow three selfing/outcrossing sister species pairs in the greenhouse in both high water and water-limited treatments and measure physiological, growth, and reproductive trait responses. Results will have important implications for our understanding of the evolution and maintenance of niche breadth.