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

职业：叶片水力、结构和气体交换的协调叶片的水力传导性(KLeaf)是整个植物液体运输的一个关键瓶颈，与叶片结构(厚度、形状、脉序结构、气孔面积)和最大气体交换速率在物种之间的巨大差异有关。此外，克利夫与特定物种的气体交换是动态联系的。在一系列系统和机理研究中，将检验下列特定假说：(1)克里夫在植物液压系统中施加一致的阻力比例，限制了最大的气体交换速率；(2)克里夫受脉序结构的限制；(3)克里夫是动态的，在低光照下下降，并在叶片脱水和衰老期间，由于木质部受阻和/或细胞膜性质的变化；这些动态与气体交换的变化重要相关；(4)克里夫跨物种协调，具有与通过叶片的水通量和每面积的气体交换相关的结构特征。这项工作将集中在这些过程的机理基础和对整个植物功能的影响上。夏威夷原生物种和入侵物种将在普通花园和夏威夷显著的自然湿度和土壤年龄梯度上进行研究。特别关注原生相思树叶水力特性在异质形成期的变化。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。这些研究将为理解叶片中水分运输和碳同化的整合开辟新的天地。这项工作将提供有关叶片导水率在植物水分流动中的作用的程度、变异、机理基础和动态性质的详细信息，以及在叶片性状多样性的进化和功能中的作用。这项研究将与夏威夷大学的本科生和研究生课程教学相结合，并与一个新的导师计划相结合，该计划将基于对独特的、迷人的夏威夷植物的研究，为夏威夷原住民提供更多的科学培训和职业机会。在夏威夷研究、教育和外展的综合指导中，土著本科生将在学期期间接受兼职指导，在暑期接受全职指导，从事研究、课程开发和推广工作，基础是夏威夷植物生物学。被指导的学生将通过设计网络课程，进行教育旅行，以及每年在大学和高中以及科学会议上发表演讲，向更广泛的社区传播知识。综合研究和教育将从根本上促进对树叶生理、进化和功能生态学的了解；为夏威夷原住民提供接触科学的途径；为科学家和教育工作者创造关于夏威夷植物生物学的资源；并增加全球对独特夏威夷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.