The Evolution of the Worldwide Leaf Economic Spectrum (WLES) in Helianthus

来自世界各地的植物在其叶形态和生理特征上差异很大。 虽然一些叶子特征的组合在自然界中被反复发现，但其他的却没有。 这表明，观察到的性状组合在不同生境中对碳增益和植物生产力具有经济优势，从而反映了适应性进化，或者这些性状组合是遗传上唯一可能的。该项目将测试被确定为全球叶经济谱（WLES：叶光合作用，氮，厚度和寿命）的性状组合是否反映了不同环境的成功生态和进化解决方案。 首先，该项目将比较27种向日葵物种（向日葵属），以了解在考虑进化关系时，特定性状组合是否稳健，以及它们是否与特定环境中的成功相关，从而支持适应性进化。 第二，该项目将测试在低营养条件下的人工选择是否会导致WLES预测的性状组合，以及是否存在任何遗传约束。 期望的是，许多性状组合是可能的（即没有遗传约束），在自然界和管理系统中发现的WLES性状组合代表植物策略，是快速资源获取和更大的资源保护不同环境之间的最成功的妥协。 更好地了解WLES叶性状及其与低资源栖息地成功的关联可能有助于改善驯化的向日葵，这是一种主要的油料作物，在美国种植面积超过200万英亩。 研究结果还将进一步提高预测随着气候变化，哪些植物将在自然和管理的栖息地中取得成功的能力。 这项研究将为高中学生和未来的科学教师提供独特的培训。

Plants from around the world vary considerably in their leaf morphological and physiological traits. Although some combinations of leaf traits are found repeatedly in nature, others are not. This suggests either that the observed trait combinations are economically advantageous for carbon gain and plant productivity in different habitats, and thus reflect adaptive evolution, or that these are the only trait combinations that are genetically possible. The project will test whether trait combinations identified as the Worldwide Leaf Economic Spectrum (WLES: leaf photosynthesis, nitrogen, thickness, and lifespan) reflect successful ecological and evolutionary solutions to different environments. First, the project will compare 27 species of sunflower species (Helianthus), to see whether particular trait combinations are robust when evolutionary relationships are accounted for, and whether they are associated with success in particular environments, and thus support adaptive evolution. Second, the project will test whether artificial selection under low nutrients results in trait combinations predicted by the WLES, and whether there are any genetic constraints. The expectation is that many trait combinations are possible (i.e. no genetic constraints) and that the WLES trait combinations found in nature and managed systems represent plant strategies that are the most successful compromises between rapid resource acquisition and greater resource conservation for different environments. A greater understanding of WLES leaf traits and their association with success in low resource habitats may contribute to the improvement of domesticated Helianthus annuus, which is a major oilseed crop with over 2 million acres in cultivation in the US. The results will also further the ability to predict which plants will be successful in natural and managed habitats as climates change. The study will provide unique training for high school students and future science teachers.