Response to Crowding and Vegetation Shade in Impatiens capensis: Genetic Variation and Fitness Consequences

小施密特9306637 许多植物表现出显着的茎伸长和其他形态的反应减少的比例的红色到远红光（R：FR）的植被遮荫的特点;最近的生理研究表明，这些反应可以诱导的R：FR的光反射到植物茎的邻居。 植物生理学家已经提出，响应于降低的R：FR的芽伸长是有利的，因为它使植物能够感知并避免对光的竞争。 另一方面，芽伸长被认为在低密度下是不利的。 这里提出的研究将在进化背景下对这些预测进行首次测试。 通过研究一年生野生稻自然种群在人工密度下的伸长与适合度之间的关系， 凤仙 capensis （jewelweed或touch me not），施密特博士将确定响应于低R：FR的伸长是否在拥挤的林分中有利，但在低密度下不利。 此外，通过使用R：FR来诱导或抑制伸长，具有“适当”和“不适当”形态的实验植物的性能可以在低密度和密集的冠层中进行比较。 施密特博士还将研究自然种群内和自然种群之间响应R：FR的遗传变异，以确定这种特性进化的潜力，并测试种群之间响应光质量的适应性分化。 数量遗传分析、种群分化和适应研究以及在不同环境中选择的直接测量的整合将提供关于生态上重要的功能性状的进化的有价值的信息。 本研究将整合遗传学，生理学和种群生物学的方法来研究适应性可塑性，并将介绍使用R：FR操纵形态植物种群生物学家的生理方法。%%% 这些结果将有助于了解植物如何在自然群落中相互作用，并将为当前植物对光谱质量反应的分子遗传学和生理学研究提供生态和进化背景。 这项工作也将是相关的农业和林业，因为它将提供有用的信息，如何响应R：FR影响性能和产量密集的立场。

9306637 Schmitt Many plants display striking stem elongation and other morphological responses to the reduced ratio of red to far red light (R:FR) characteristic of vegetation shade; recent physiological studies have shown that these responses can be induced by the R:FR of light reflected onto plant stems by neighbors. Plant physiologists have suggested that shoot elongation in response to reduced R:FR is advantageous because it enables plants to sense and avoid competition for light. On the other hand, shoot elongation is thought to be disadvantageous at low density. The study proposed here will provide the first test of these predictions in an evolutionary context. By examining the relationship between elongation and fitness at manipulated densities in natural populations of the common native annual Impatiens capensis (jewelweed or touch me not), Dr. Schmitt will determine whether elongation in response to low R:FR is favored in crowded stands, but disadvantageous at low density. Moreover, by using R:FR to induce or inhibit elongation, the performance of experimental plants with "appropriate" and "inappropriate" morphologies can be compared both at low density and in dense canopies. Dr. Schmitt will also examine genetic variation in response to R:FR within and between natural populations to determine the potential for this trait to evolve and test for adaptive differentiation in response to light quality among pop ulations. The integration of quantitative genetic analysis, studies of population differentiation and adaptation, and direct measurement of selection in different environments will provide valuable information about the evolution of an ecologically important functional trait. This research will integrate genetic, physiological, and population biology approaches to the study of adaptive plasticity, and will introduce physiological methods for using R:FR to manipulate morphology to plant population biologists. %%% The results will contribute to understanding how plants interact in natural communities and will provide an ecological and evolutionary context for current research on the molecular genetics and physiology of plant responses to light spectral quality. This work will also be relevant to agriculture and forestry because it will provide useful information about how response to R:FR affects performance and yield in dense stands.