Dissertation Research: Nutrient Use Efficiency in Simplified Tropical Ecosystems

[9623969]热带简化生态系统的养分利用效率。植物利用养分的效率是一个主题，它将从叶子到植物再到整个生态系统的许多尺度上的生理过程联系在一起。叶片和植物水平上养分利用效率的差异能否放大，以预测生态系统水平上的养分利用效率？将在一系列简化的热带生态系统中以不同的尺度调查养分利用效率：树木单一栽培，树木和一种非常不同的生命形式-大型多年生单子叶植物的混合栽培。养分利用效率将在叶片水平上计算，即单位养分含量的最大潜在光合速率；在植物水平上，与养分吸收相关的总生物量；在生态系统层面，生物量生产与养分供应的关系。这项研究将提供一个机会来比较不同尺度和不同生命形式的养分利用效率。了解叶片和植物水平养分利用效率与生态系统养分利用之间的反馈关系，将有助于深入了解生物多样性的功能作用。它还将为恢复退化土地和设计有效保存养分的土地利用系统提供有力的工具。

9623969 Ewel Nutrient use efficiency in simplified tropical ecosystems. The efficiency with which plants use nutrients is a theme that unites physiological processes at many scales - from leaves, to plants, to whole ecosystems. Can differences in nutrient use efficiency at the leaf and plant level be scaled up to predict nutrient use efficiency at the ecosystem level? Nutrient use efficiency will be ilvestigated at different scales in a series of simplified tropical ecosystems: tree monocultures, and polycultures of trees and a very different life form - large, perennial monocots. Nutrient use efficiency will be calculated at the leaf level, as the maximum potential photosynthetic rate per unit nutrient content; at the plant level, as total biomass produced relative to nutrient uptake; and at the ecosystem level, as biomass production relative to nutrient supply. The study will provide an opportunity to compare nutrient use efficiency across scales, and across life forms. Understanding feedbacks between nutrient use efficiency at the leaf and plant level, and ecosystem nutrient use, will provide insight into the functional role of biodiversity. It will also provide a powerful tool in enabling restoration of degraded lands, and design of land use systems that are effective at nutrient conservation.