CAREER: Integrating biochemical, physiological and morphological responses of plants to changes in water availability

这项研究阐述了在地中海气候生态系统中，叶、茎和根的特征如何共同影响生物对不同降水情景的反应。干旱和半干旱环境中的降水量在年内和年间可能变化很大，植物适宜性取决于在这些事件期间对水的快速或有效利用。适应干旱系统的植物具有大量的叶、茎和根特征，这些特征有助于最大限度地减少水分胁迫，但目前尚不清楚这些水分保持特征是否限制了植物对降水事件的快速反应能力，以及水分获取和保持特征如何与植物适合性相对应。拟议的研究围绕两个问题进行：(1)对可用水突然变化的反应能力与水资源保护战略之间是否存在权衡，以及(2)与水分获取和保护有关的特征如何与植物适应性相关，这如何取决于降雨量和频率？这些问题将在南加州沿海鼠尾草灌木群落的四种一年生和六种多年生物种中进行研究。了解生化、形态和生理过程如何导致生物对环境变化的综合反应，将改善社区对气候变化反应的预测模型。地中海气候生态系统是世界上最有可能受到气候变化影响的地区之一，拟议的工作将收集恢复这些独特的、受到威胁的生态系统所需的关键信息。例如，了解物种在各种降水情景下如何利用水，可能会通过允许资源管理者识别以类似方式使用资源的本地物种，从而改善被外来植物物种入侵的系统的恢复工作，这可能会增加群落对入侵的弹性。这份职业计划通过监督和独立研究(本科、高中暑期实习)以及本科和高中水平的课程，代表了一个完全整合的研究和教育计划。这项研究将在一个小型本科生机构进行，每年将为四名本科生研究人员提供提高研究、分析和沟通技能的机会。这些学生中的大多数将继续攻读研究生课程，或者从事生态学或植物生物学方面的职业。来自四门高级生物课程的学生将直接参与收集和分析拟议中的实地实验的数据。来自传统代表性不足群体的高中理科学生将参加PIS实验室的每周会议，以建立一个温室实验，并收集和分析数据。高中生还将参加周末的实地考察，并有机会进行暑期实习。这笔研究补助金还将有助于为担任PI的年轻女教授制定长期计划。PI将通过公开讲座、当地修复活动以及继续与欧文牧场保护协会的资源管理人员合作，吸引科学界、资源管理人员和普通公众的参与。

This research addresses how leaf, stem and root traits collectively influence organismal responses to different precipitation scenarios across multiple species in a Mediterranean-climate ecosystem. Precipitation in arid and semi-arid environments can vary strongly within and across years and plant fitness can depend on rapid or efficient utilization of water during these events. Plant species adapted to arid systems possess numerous leaf, stem and root traits that serve to minimize water stress, but it remains unclear whether these water conservation traits limit a plant's ability to rapidly respond to precipitation events and how water acquisition and conservation traits correspond to plant fitness. The proposed research is organized around two questions: (1) is there a trade-off between the ability to respond to sudden changes in water availability and a water conservation strategy, and (2) how do traits pertaining to water acquisition and conservation correlate with plant fitness and how does this depend on the magnitude and frequency of precipitation? These questions will be examined in four annual and six perennial species from a southern California coastal sage scrub community. Understanding how biochemical, morphological and physiological processes result in integrated organismal responses to environmental variation will improve predictive models of community response to climate change. Mediterranean-climate ecosystems are among the regions of the world most likely to be affected by climate change and the proposed work will collect critical information needed to restore these unique, threatened ecosystems. For example, understanding how species use water under a variety of precipitation scenarios may improve restoration efforts in systems invaded by exotic plant species by allowing resource managers to identify native species that use resources in a similar way, which may increase community resilience to invasion. This CAREER proposal represents a fully integrated plan of research and education though supervised and independent research (undergraduate, high school summer internships) and courses at the undergraduate and high school level. The study will be conducted at a small, undergraduate institution and will provide four undergraduate researchers per year with opportunities to enhance research, analytical and communication skills. Most of these students will continue into graduate programs or pursue careers in ecology or plant biology. Students from four upper-division biology courses will be directly involved in collecting and analyzing data from the proposed field experiment. High school science students from traditionally underrepresented groups will participate in weekly meetings at the PIs lab to set up a greenhouse experiment and collect and analyze data. High school students will also participate in weekend field trips and have the opportunity to conduct summer internships. The research grant will also help to establish long-term plots for the young female professor who is serving as the PI. The PI will engage the scientific community, resource managers and the general public through public lectures, local restoration activities, and continued collaborations with resource managers at the Irvine Ranch Conservancy.