Evolutionary Ecophysiology of Nutrient Relations in a Desert Sunflower of Hybrid Origin

土壤肥力是自然生态系统和管理生态系统中植物生产力的重要决定因素。 来自低营养栖息地的原生植物的特征被假设为解释原生植物生态和进化成功的特征。 这些性状通常被认为允许植物减少营养需求，增加保留和/或增加吸收能力。然而，这些个体特征的生态和进化优势及其遗传基础尚未得到证实。 本研究将利用一种杂交起源的沙漠向日葵及其祖先亲本物种，研究贫瘠生境中植物营养关系性状的生态学和进化。 与其祖先的亲本物种相比，向日葵是低营养栖息地特有的，具有与低营养适应一致的特征。 该研究将1）测试个体性状的优势，2）确定这些性状的遗传和基因组基础，3）确定这些性状如何对选择做出反应。 这些实验将作为一系列受控环境和实地研究进行。 生态生理学、数量遗传学和基因组学观点的整合将提供对形成H.更一般地说，是选择过程导致了对低营养栖息地的适应。 这项研究将有助于了解在边际条件下最大限度地提高作物产量的性状。 向日葵（Helianthus annuus）是H. Alcohus和驯化的H.一年生植物是重要的经济作物。 因此，H. 黑曲霉和代表其假定祖先的合成杂交种可以作为基因的供体来改进H。在低养分条件下提高一年生植物的生产力，减少肥料需求，减少农业径流的影响。 这项研究也将为众多本科生提供一个获得大量研究经验的机会。

Soil fertility is an important determinant of plant productivity in natural and managed ecosystems. Native plants from low nutrient habitats have been characterized for traits that are hypothesized to account for the native plant ecological and evolutionary success. These traits are generally thought to allow plants to reduce nutrient demand, increase retention, and/or increase uptake capacity. However, the ecological and evolutionary advantages of these individual traits, and their genetic bases, have not been demonstrated. The proposed research will use a desert sunflower species of hybrid origin and its ancestral parent species to investigate the ecology and evolution of plant nutrient relation traits in infertile habitats. Compared to its ancestral parent species, Helianthus anomalus is endemic to a low nutrient habitat and has traits consistent with low nutrient adaptation. The research will 1) test the advantage of individual traits and 2) identify the genetic and genomic basis of those traits, and 3) determine how those traits respond to selection. The experiments will be carried out as a series of controlled environment and field studies. The integration of ecophysiological, quantitative genetic, and genomic perspectives will provide insight into the evolutionary forces that have shaped H. anomalus, and more generally to the process of selection that leads to adaptation to low nutrient habitats. This study will contribute to the understanding of traits that could maximize crop productivity under marginal conditions. Helianthus annuus is one of the ancestral parents of H. anomalus and domesticated H. annuus is an economically important crop species. Thus, H. anomalus and synthetic hybrids representing its putative ancestors may serve as donors for genes to improve H. annuus productivity under lower nutrient conditions, reducing fertilizer requirements and decreasing impacts of agricultural runoff. This study will also provide an opportunity for numerous undergraduate students to gain a substantial research experience.