Collaborative Research: The Evolution of Leaf Form in Viburnum (Adoxaceae)

“该奖项是根据2009年美国复苏和再投资法案（公法111-5）资助的。“陆生植物在叶形的许多方面都表现出显着的变化。叶子是光合作用的主要场所，因此是植物生长和最终健康的主要监护人。先前的工作表明，在给定的环境中，特定的叶子性状存在最佳值，可以最大限度地提高生长，从而预测某些叶子形式将在某些条件下进化。然而，进化对外部压力（如气候）的反应可能会受到限制，因为叶子在发育和功能上是整个植物的组成部分。尽管叶在植物生态适应中的作用长期以来一直受到关注，但很少有研究成功地记录了叶性状与环境相关的一致进化变化。这个合作项目将开发植物谱系荚属（Viburnum）（豆科），一个广泛分布的约168种木本灌木和树木的群体，作为研究生态学和叶形进化的模型系统。荚属植物非常适合解决这个问题，因为它的叶子形状和大小具有显着的多样性，并且已经知道了很多关于组内进化关系的信息。跨学科的PI团队将收集来自两个常见花园的生理数据，来自植物标本馆的解剖和环境数据，以及用于系统发育分析的分子序列数据，以产生关于叶进化的独特的全谱系观点，同时详细和广泛。他们将直接测试关于茎和叶共同进化的几个假设，叶片水分利用的某些方面与光合能力的脱钩，以及特定叶片性状对环境条件的响应。一个预测是，相当大的叶片形状多样性已经在一个相对狭窄的气候空间内进化，这表明其他因素在历史上对塑造叶片结构和功能的进化轨迹更为重要。这项工作的结果可能与预测植物对快速气候变化的反应直接相关。这项工作还将导致开发新的在线社区范围的教学和研究资源，如用于解剖研究的大型叶片收藏。与皮博迪自然历史博物馆和来自国际扶轮地区普罗维登斯的公立学校教师一起，PI还将为纽黑文和普罗维登斯学区的小学和高中制定两个“树叶多样性”教育模块。

"This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5)." Terrestrial plants display remarkable variation in many aspects of leaf form. Leaves serve as main sites for photosynthesis, and are thus primary custodians of plant growth and ultimately, fitness. Previous work suggests that there are optimal values for particular leaf traits in a given environment that will maximize growth, and thus predicts that certain leaf forms will evolve under certain conditions. However, evolutionary response to external pressures such as climate may be constrained, because leaves are developmentally and functionally integrated parts of the whole plant. In spite of the long-standing interest in the role of leaves in plant ecological adaptation, few studies have successfully documented consistent evolutionary shifts in leaf traits in relation to environment. This collaborative project will develop the plant lineage Viburnum (Adoxaceae), a widespread group of approximately 168 species of woody shrubs and trees, as a model system for investigations into the ecology and evolution of leaf form. Viburnum is ideally suited for this problem as it exhibits a remarkable diversity of leaf shapes and sizes, and much is already known regarding evolutionary relationships within the group. The interdisciplinary PI team will collect physiological data from two common gardens, anatomical and environmental data from herbarium collections, and molecular sequence data for phylogenetic analyses to produce a unique, whole-lineage perspective on leaf evolution that is simultaneously detailed and broad. They will directly test several hypotheses regarding stem and leaf co-evolution, the decoupling of certain aspects of leaf water use from photosynthetic capacity, and the evolution of particular leaf traits in response to environmental conditions. One prediction is that considerable leaf shape diversity has evolved within a relatively narrow climate space, suggesting that other factors have historically been more important in shaping the evolutionary trajectory of leaf structure and function. Results from this work may be directly relevant to predicting plant response to rapid climate change. This work will also result in the development of new online community-wide teaching and research resources, such as a large leaf collection for anatomical study. In conjunction with the Peabody Museum of Natural History and public school teachers from the Providence, RI area, the PI's will also develop two 'leaf diversity' education modules targeted for elementary and high school levels in the New Haven and Providence school districts.