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

在自然和人工管理的生态系统中，土壤肥力是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具有一些特征，这些特征被认为是原生植物生态和进化成功的原因。这些特性通常被认为允许植物减少养分需求，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。本研究拟以一种杂交荒漠向日葵及其祖先亲本物种为研究对象，探讨荒漠向日葵不育生境下植物营养关系性状的生态学和进化。与其祖先亲本种相比，异常向日葵是低营养生境的特有物种，具有低营养适应特征。这项研究将1)测试个体特征的优势，2)确定这些特征的遗传和基因组基础，3)确定这些特征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、定量遗传学和基因组学观点的整合将提供对形成异常人的进化力量的洞察，以及更广泛地了解导致适应低营养栖息地的选择过程。这项研究将有助于了解在边际条件下作物产量最大化的性状。向日葵是黄花的祖先亲本之一，驯化后的黄花是一种重要的经济作物。因此，在低营养条件下，代表其假定祖先的反常稻和合成杂交种可能作为基因的供体，提高了黄稻的生产力，减少了对肥料的需求，减少了对农业径流的影响。这项研究也将为众多本科生提供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.