Resource Acquisition, Allometry, and Growth of Individuals within Competing Plant Populations

9630397 Bazzaz竞争在植物生态和进化中的核心作用是一个被广泛接受的概念。然而，我们对竞争机制的理解仍然有限，部分原因是它没有强大的机制基础。这个项目提出了一种新的、多层次的方法来研究植物竞争。该方法结合了一种描述资源竞争生理方面的新方法，以及传统的增长分析和人口统计技术。所选择的系统是两个白桦树种(白桦和白桦)田间单一栽培的竞争性相互作用，这两个树种对光、水和养分的要求不同。将对资源吸收和林分发展进行为期两年的监测。第三年将专门用于处理植物和土壤样本，并对数据进行建模和合成。这些结果将使我们能够评估在林分发育的不同阶段对光和养分的竞争的程度和相对重要性，并对目前关于植物之间资源竞争的一些假说进行实证检验。这项研究将是弥合成熟的植物竞争和林分发育现象学模型与竞争生理机制之间的差距的重要一步。

9630397 Bazzaz The central role of competition in the ecology and evolution of plant is a widely accepted concept. Yet, our understanding of the mechanisms of competition is quit limited, in part because it does not have a strong mechanistic basis. This project proposes a novel, multi- level approach to the study of plant competition. The approach combines a new method for characterizing physiological aspects of resource competition with traditional growth analyses and demographic techniques. The system chosen for the study is competitive interactions in experimentally established field monocultures of two birch species, (Betula alleghaniensis and B. populifolia), that differ in their requirements for light, water and nutrients. Resource uptake and stand development will be monitored for two years. A third year will be devoted to processing plant and soil samples and to modeling and synthesizing data. The results will allow us to assess the magnitude and relative importance of competition for light and nutrients at various stages of stand development, and to empirically test a number of current hypotheses regarding resource competition among plants. The research will be an important step in bridging the gap between well-developed phenomenological models of plant competition and stand development, and the physiological mechanisms of competition.