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

在自然和管理的生态系统中，土壤肥力是植物生产力的重要决定因素。来自低营养生境的本地植物的特征被认为是解释本地植物生态和进化成功的原因。这些特性通常被认为可以使植物减少营养需求，增加保持量，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。这项研究将利用一种杂交起源的沙漠向日葵物种及其祖先亲本物种来研究贫瘠生境中植物营养相关性状的生态和进化。与其祖先种相比，向日葵是低营养生境特有的，具有与低营养适应相一致的特征。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)确定这些特征对选择的反应。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结合将有助于深入了解形成异常菌的进化力量，以及更广泛地说，有助于了解导致适应低营养生境的选择过程。这项研究将有助于理解在边际条件下可以最大限度地提高作物生产力的性状。向日葵是异型向日葵的祖先之一，驯化向日葵是一种重要的经济作物。因此，异常草和代表其可能祖先的合成杂交种可以作为基因的供体，在较低的营养条件下提高黄花菜的生产力，减少化肥需求，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.