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

凤仙花对拥挤和植被遮荫的反应：遗传变异和适应性后果

• 批准号: 9806858
• 负责人: Johanna Schmitt
• 金额: $ 30万
• 依托单位: Brown University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-08-15 至 2002-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9806858&HistoricalAwards=false
• 关键词: Response; Crowding; Vegetation; Shade; Impatiens

Schmitt 9806858 Many plant species exhibit characteristic morphological and physiological responses to crowding and vegetation shade. This "shade avoidance" response is cued by a reduction in the ratio of red to far-red wavelengths (R:FR) in light transmitted through or reflected from green vegetation. This R:FR signal is perceived by light-sensing molecules known as phytochromes. It has been hypothesized that phytochrome-mediated shade avoidance responses are beneficial to plants because it enables them to anticipate and avoid competition for light in dense stands. Recent results from a related project strongly support this hypothesis. In a field experiment, phytochrome-mediated stem elongation increased the reproduction of the native annual Impatiens capensis (jewelweed or touch-me-not) in dense stands, but plants induced to display the shade avoidance response at low density suffered reduced fitness relative to non-elongated plants, apparently due to an unmeasured physiological cost. The objectives of the proposed research are to investigate the possible ecological, physiological, and genetic mechanisms underlying this cost, and to quantify the frequency and pattern of natural selection on shade avoidance traits within a natural population. A specific goal is to determine whether the shade avoidance response results in increased damage from ultraviolet-B radiation due to a lack of protective pigments, and to test for genetic variation in morphological responses or sensitivity to UV-B. To address these questions, elongated and non-elongated seedlings from replicated inbred lines will be produced by manipulation of the R:FR cue, and planted into a series of treatments in a natural population and an experimental garden. The results of this project will provide important information about the role of phytochrome-mediated shade avoidance responses in natural plant populations, and will provide an ecological and evolutionary context for current research on the molecular, genetic, developmental, and physiological mechanisms underlying plant responses to light. It will also help to inform selection strategies for crop improvement and provide an ecological context for recent proposals to increase yield by genetically engineering crops in which shade avoidance responses are blocked. The results will also be valuable for understanding how wild plants will respond to increasing UV radiation levels during the current period of rapid global change.

施密特 9806858 许多植物物种表现出特征性的形态和生理特征 对拥挤和植被阴影的反应。这种“避荫”反应 是通过减少红远红波长（R：FR）的比例， 透过或反射自绿色植物的光。R：FR 信号被称为光敏色素的感光分子感知。 它 已经假设光敏色素介导的避荫反应 对植物是有益的，因为它使它们能够预测和避免 在茂密的林分中争夺光线。相关项目的最新成果 强烈支持这一假设。 在一次实地实验中， 光敏色素介导的茎伸长增加了 本地一年生凤仙花capensis（珠宝草或触摸我不）在密集 林分，但植物诱导显示避荫反应在低 密度相对于非伸长的植物遭受降低的适合度， 显然是由于无法测量的生理代价。 的目标 拟议的研究是调查可能的生态，生理， 以及这种成本背后的遗传机制，并量化 和自然选择模式对避荫性状的影响 人口 一个具体的目标是确定是否避荫 响应导致紫外线B辐射的损害增加， 缺乏保护色素，并测试遗传变异， 形态学反应或对UV-B的敏感性。为了解决这些问题， 来自复制的近交系的伸长和非伸长幼苗将被 通过操纵R：FR线索产生，并种植到一系列的 在自然种群和实验花园中进行处理。 本项目的研究结果将为了解光敏色素介导的避荫反应在天然植物中的作用提供重要信息 人口，并将提供一个生态和进化的背景下， 目前的分子、遗传、发育和 植物对光反应的生理机制 它还将 有助于为作物改良提供选择策略， 最近提出的通过基因改造提高产量的建议的生态背景 工程作物，其中避荫反应被阻断。 的 研究结果对于了解野生植物如何 在目前的这段时间里， 快速的全球变化。