International Research Fellowship Program: Hydraulic Conductance and Safety: Important Components of Plant Trait Spectra

[502253zanne]国际研究奖学金计划使美国科学家和工程师能够在国外进行三到二十四个月的研究。该计划的奖励为联合研究提供了机会，并利用独特或互补的设施、专业知识和国外的实验条件。该奖项将支持Amy E. Zanne博士与澳大利亚麦考瑞大学的Mark Westoby博士和加州大学伯克利分校的David Ackerly博士进行为期22个月的研究。现有理论认为木质部水力导度（与导管直径有关）应该与机械强度（与木材密度和管壁厚度有关）和避免干旱引起的栓塞（气泡阻塞水流）的能力负相关。目前尚不清楚这些水力性状是否与叶片和枝条大小或叶片结构和寿命的正交谱紧密相关，或者它们是否代表了它们自己的主要性状变异谱。这个为期22个月的项目量化了这些特征在季节、年降雨量和物种生物地理历史上的差异。它还检查了植物水力学和这些其他主要光谱之间的关系。植物性状光谱的研究构成了Westoby和ackely实验室大部分工作的基础。该项目将在澳大利亚新南威尔士州沿海到内陆降雨梯度的地点进行，并将在两个夏季和冬季测量水力特性。在这些地点已经记录了许多关键的叶片特性（例如叶片寿命、结构、大小、营养成分和气体交换率），使它们成为该项目的理想地点。这个项目将分为三个步骤。首先，性状变异将根据立地降雨和季节进行评估。其次，物种可塑性将在两个地点的物种幼苗上进行研究，这些物种的水力特性差异很大。最后，将利用阿克利实验室的分析，根据物种生物地理历史，对澳大利亚不同地点的物种特征进行比较。韦斯托比博士将支持澳大利亚的实地和实验室研究，阿克利博士将支持生物地理分析。该项目在植物水力学和其他关键植物性状光谱之间建立了重要的概念桥梁，并将补充澳大利亚（韦斯托比）和加州（阿克利）正在进行的项目。它将大大增加对植物对变化环境的反应的理解（与预测全球气候变化影响有关）。

0502253ZanneThe International Research Fellowship Program enables U.S. scientists and engineers to conduct three to twenty-four months of research abroad. The program's awards provide opportunities for joint research, and the use of unique or complementary facilities, expertise and experimental conditions abroad.This award will support a twenty-two-month research fellowship by Dr. Amy E. Zanne to work with Dr. Mark Westoby at Macquarie University in Australia for eleven months, and with Dr. David Ackerly at the University of California, Berkeley for eleven months.Existing theory suggests xylem hydraulic conductance (related to vessel diameter) should be negatively related to mechanical strength (related to wood density and vessel wall thickness) and the ability to avoid drought-induced embolisms (air bubbles blocking water flow). It is unclear whether these hydraulic traits are tightly linked to the orthogonal spectra of leaf and twig size or leaf structure and longevity, or whether they represent their own major spectrum of trait variation. This 22-month project quantifies how these traits differ across seasons, annual rainfall, and species biogeographic histories. It also examines relationships between plant hydraulics and these other major spectra. Studies of plant trait spectra form the basis for much of the work in the Westoby and Ackerly labs. The project will be conducted at sites along a coastal to inland rainfall gradient in New South Wales, Australia, and hydraulic traits will be measured during two summer and winter seasons. Many key leaf properties have already been documented at these sites (e.g. leaf lifespan, structure, size, nutrient content, and gas exchange rates), making them ideal locations for this project. The project will entail three steps. First, trait variation will be evaluated relative to site rainfall and season. Second, species plasticity will be examined on seedlings of species from the two sites varying widely in hydraulic properties. Finally, species traits will be compared across sites in Australia based on species biogeographic histories, using analyses from Ackerly's lab. Dr. Westoby will support field and laboratory research in Australia, and Dr. Ackerly will support biogeographic analyses.This project builds important conceptual bridges between plant hydraulics and other key plant trait spectra and will complement ongoing projects in Australia (Westoby) and California (Ackerly). It will substantially increase understanding of plant responses to changing environments (relevant for predicting global climate change impacts).