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: 9708114
• 负责人: Johanna Schmitt
• 金额: $ 9万
• 依托单位: Brown University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-08-15 至 1999-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9708114&HistoricalAwards=false
• 关键词: Response; Crowding; Vegetation; Shade; Impatiens

9708114 Schmitt Many plant species exhibit characteristic morphological responses to crowding and vegetation shade, such as stem elongation and reduced branching. This "shade avoidance response" is cued by a reduction in the ratio of red to far-red wavelengths (R:FR) in light transmitted or reflected from green vegetation; this R:FR signal is perceived by light-sensing molecules called phytochromes. It has been hypothesized that phytochrome-mediated shade avoidance responses are beneficial to plants by enabling them to anticipate and avoid competition for light in dense stands. Recent results from this project strongly support this hypothesis. In a field experiment, stem elongation increased the reproduction of the common annual Impatiens capensis in dense stands, but plants induced to display the shade avoidance response at low density suffered reduced fitness relative to nonelongated plants, apparently due to an unmeasured physiological cost. The goals of the proposed research are to examine the genetic basis of the shade avoidance response and potential mechanisms for selection on the response in the field, and to test for physiological, ecological, and genetic costs of the response. Replicated inbred lines differing in the magnitude of morphological response to R:FR will be planted into a natural population at manipulated densities and group compositions to study the level at which selection acts on shade avoidance traits. Elongated and nonelongated seedlings will be grown under different levels of water and nutrients, to determine the conditions under which shade avoidance traits may be costly. This research will integrate genetic, physiological, and population biology approaches to the study of phytochrome-mediated shade avoidance responses in plants. It will provide important insights into the role of these responses in natural populations. The results will also provide an ecological and evolutionary context for current research by plant molecular biolog ists and developmental biologists on the underlying genetic basis for plant responses to light. Since most crops are grown in dense stands, this study will also provide insight into possible selection strategies for improvement of agricultural yields.

9708114施密特许多植物物种对拥挤和植被阴影的形态反应具有特征性的形态反应，例如茎伸长和分支减少。 这种“避免阴影响应”是通过在绿色植被传播或反射的光线或反射的红色波长（r：fr）之比的降低来暗示的；该R：FR信号被称为植物色素的光感应分子所感知。 据推测，植物色素介导的避免避免的阴影反应通过使植物能够预测并避免在茂密的林分中获得光线竞争，从而对植物有益。该项目的最新结果强烈支持这一假设。 在野外实验中，茎伸长增加了密集林分中常见的年度凤仙花的繁殖，但是相对于非长期植物，诱导的植物在低密度下表现出避免阴影的避免反应，显然是由于未衡量的生理成本所致。拟议的研究的目标是检查避免阴影反应的遗传基础和对野外反应的选择的潜在机制，并测试反应的生理，生态和遗传成本。 复制的近交系在对R：FR的形态反应的大小上有所不同。 伸长和非延长的幼苗将在不同水平的水和养分下生长，以确定避免阴影特征的条件可能是昂贵的。 这项研究将使植物介导的植物的避免阴影反应的研究整合遗传，生理和种群生物学方法。 它将为这些反应在自然种群中的作用提供重要的见解。 该结果还将为植物分子生物学IST和发育生物学家的当前研究提供生态和进化的环境，这是植物对光的反应的基本遗传基础。 由于大多数农作物都在茂密的林分中种植，因此这项研究还将深入了解改善农业产量的选择策略。