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

来自世界各地的植物在叶的形态和生理特征上有很大的差异。尽管一些叶子特征的组合在自然界中被反复发现，但另一些则不是。这表明，所观察到的性状组合对不同生境的碳增益和植物生产力具有经济优势，因此反映了适应性进化，或者这些性状组合是唯一可能的遗传性状组合。该项目将测试被确定为全球叶片经济光谱(WLES：叶片光合作用、氮素、厚度和寿命)的性状组合是否反映了针对不同环境的成功的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)，看看当考虑到进化关系时，特定的特征组合是否强大，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。其次，该项目将测试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限制。人们的期望是，许多性状组合是可能的(即没有遗传限制)，而在自然界和管理系统中发现的WLES性状组合代表了植物策略，这些策略是快速获取资源和针对不同环境更好地保护资源之间最成功的折衷。更多地了解WLES叶片特征及其与低资源生境成功的关联可能有助于改良驯化的向日葵，这是一种主要的油料作物，在美国种植面积超过200万英亩。这一结果还将进一步提高预测哪些植物将在自然和管理的生境中随着气候变化而成功的能力。这项研究将为高中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.