CAREER: The coordination of leaf hydraulics, structure and gas exchange

叶片水力学、结构和气体交换的协调叶片水力导度（Kleaf）是整个植物液体运输的关键瓶颈，与不同物种在叶片结构（厚度、形状、脉结构、气孔孔面积）和最大气体交换率方面的巨大多样性有关。此外，Kleaf与给定物种的气体交换动态联系在一起。在一系列系统和机械的研究中，将检验以下具体假设：(1)克利夫在工厂液压系统中施加一致比例的阻力，限制气体交换的最大速率；(2)叶片受脉状结构约束；(3)叶片是动态的，在低辐照和叶片脱水和老化过程中，由于木质部阻塞和/或膜性质的变化，叶片呈下降趋势；这些动力学与气体交换的变化有重要关系；(4)叶片在物种间具有协调性，其结构特征与叶片水分通量和单位面积气体交换有关。这项工作将集中于这些过程的机制基础和对整个植物功能的影响。夏威夷本土物种和入侵物种将在普通花园和夏威夷戏剧性的自然湿度和土壤年龄梯度中进行研究。本文将特别关注本地金合欢异质期叶片水力特性的变化。这项研究将扩大到包括树木园种植的天南星科植物，它们的叶子非常多样化。这些研究将为理解水分运输和碳同化在叶片中相互联系的整合开辟新的领域。这项工作将提供叶片水力导度在植物水流中的作用的范围、变化、机制基础和动态性质，以及叶片性状多样性的演变和功能的详细信息。这项研究将与夏威夷大学的本科和研究生课程教学相结合，并与一项新的指导计划相结合，该计划将基于对独特而迷人的夏威夷植物群的研究，为夏威夷本地人提供更多的科学培训和职业机会。在夏威夷研究、教育和推广综合指导项目中，土著本科生将在学期期间接受兼职指导，在夏季接受全职指导，以夏威夷植物生物学为基础，进行研究、课程开发和推广。受指导的学生将通过设计网络课程、进行教育之旅、每年在大学和高中以及在科学会议上发表演讲，向更广泛的社区传播知识。整合的研究和教育将从根本上促进对叶片生理学、进化和功能生态学的理解；为夏威夷原住民提供接触科学的机会；为科学家和教育工作者创建夏威夷植物生物学资源；并提高全球对夏威夷独特生物群的认识和了解。

CAREER: The coordination of leaf hydraulics, structure and gas exchangeThe leaf hydraulic conductance (Kleaf) is a critical bottleneck in whole-plant liquid transport, associated with the tremendous diversity across species in leaf structure (thickness, shape, venation architecture, stomatal pore area) and maximum rates of gas exchange. Additionally, Kleaf is dynamically linked with gas exchange for given species. In a series of systematic and mechanistic studies, the following specific hypotheses will be tested: (1) Kleaf imposes a consistent proportion of resistance in the plant hydraulic system, constraining maximum rates of gas exchange; (2) Kleaf is constrained by venation architecture; (3) Kleaf is dynamic, declining in low irradiance, and during leaf dehydration and ageing, due to xylem blockage and/or changes in membrane properties; these dynamics are importantly related to changes in gas exchange; (4) Kleaf is coordinated across species with structural traits associated with water flux through the leaf and gas exchange per area. This work will focus on both the mechanistic bases for these processes and the implications for whole plant function. Native Hawaiian species and invasive species will be studied in common gardens and across the dramatic natural moisture and soil age gradients of Hawai'i. Special focus will be given to the variation of of leaf hydraulic properties in the heteroblastic stages of native Acacia koa. The study will be expanded to include arboretum-grown species of Araceae with exceptionally diverse leaves. These studies will break new ground toward understanding of the integration of water transport and carbon assimilation at their nexus in the leaf. The work will provide detailed information of the extent, variation, mechanistic basis and dynamic nature of the role of leaf hydraulic conductance in the flow of water through plants, and in the evolution and function of diversity in leaf traits. The research will be integrated with undergraduate and graduate course teaching at University of Hawai'i, and with a new mentorship program to provide increased access for native Hawaiians to scientific training and careers, based on study of the unique, fascinating Hawaiian flora. In the Integrated Mentorship in Hawaiian Research, Education and Outreach, indigenous undergraduate students will be mentored part-time during semesters and full-time during summers in research, curriculum development, and outreach, grounded in Hawaiian plant biology. Mentored students will disseminate knowledge to the wider community by designing web curricula, giving educational tours, and by presenting annually in colleges and high schools, and at scientific meetings. The integrated research and education will contribute fundamentally to the understanding of leaf physiology, evolution and functional ecology; provide access for native Hawaiians to science; create resources on Hawaiian plant biology for scientists and educators; and increase global awareness and understanding of the unique Hawaiian biota.