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

这项研究探讨了叶、茎和根性状如何共同影响地中海气候生态系统中多个物种对不同降水情景的生物反应。 干旱和半干旱环境中的降水量在年内和不同年份之间可能会有很大变化，植物的适应性可能取决于这些事件期间水的快速或有效利用。 适应干旱系统的植物物种具有许多叶、茎和根特征，可以最大限度地减少水分胁迫，但目前尚不清楚这些保水特征是否限制了植物快速响应降水事件的能力，以及水获取和保存特征如何与植物适应性相对应。 拟议的研究围绕两个问题进行组织：（1）应对水资源突然变化的能力与节水策略之间是否存在权衡；（2）与水获取和保护有关的特征如何与植物适应性相关，以及这如何取决于降水的幅度和频率？ 这些问题将在来自南加州沿海鼠尾草灌木丛群落的四种一年生植物和六种多年生植物中进行研究。 了解生化、形态和生理过程如何导致有机体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况下如何利用水，可以让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，这可能会提高群落抵御入侵的能力。 该职业提案代表了一个通过监督和独立研究（本科生、高中暑期实习）以及本科生和高中水平的课程来全面整合研究和教育的计划。 该研究将在一所小型本科院校进行，每年将为四名本科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从事生态学或植物生物学的职业。 来自四个高年级生物学课程的学生将直接参与收集和分析拟议现场实验的数据。 来自传统上代表性不足群体的高中理科学生将参加 PI 实验室的每周会议，以建立温室实验并收集和分析数据。 高中生还将参加周末实地考察，并有机会进行暑期实习。这笔研究经费还将帮助担任首席研究员的年轻女教授制定长期计划。 PI 将通过公开讲座、当地恢复活动以及与欧文牧场保护区资源管理者的持续合作，吸引科学界、资源管理者和公众参与。

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.