EAGER: Collaborative Proposal: Linking physiology and morphology in Grassland evolution via a novel analytical technique

EAGER：协作提案：通过新颖的分析技术将草原进化中的生理学和形态学联系起来

• 批准号: 2114240
• 负责人: Rita Economos
• 金额: $ 16.93万
• 依托单位: Southern Methodist University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-06-15 至 2024-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2114240&HistoricalAwards=false
• 关键词: EAGER; Collaborative; Proposal; Linking; physiology

Grasslands cover ~40% of Earth’s land surface, playing a key role in terrestrial life, global climate and critical human resources (the grass family includes all cereal crops like rice and wheat). Although they appeared ~70 million years ago, the spread of grasslands began only ~22 million years ago, with tropical savanna ecosystems present by ~8 million years ago. Grass evolution and ecosystem change likely coincided with evolving climates, landscapes and animals. The best way to identify fossil grasses is from microscopic silica pieces (“phytoliths”), left behind in sedimentary rocks when the rest of the plant has decomposed. Phytoliths have shapes characteristic of particular grass types, but no method exists that can reveal the photosynthesis type (C3 or C4) of the grass that produced them. This project tests a new method to use phytoliths to measure the chemistry of un-decomposed carbon inside them; thus, the photosynthetic type of the grasses that produced them. This will allow researchers to answer questions about the past and possible future of grasslands. For example, what grasses grew in the earliest savannas and what photosynthesis did they use? What caused the spread of the C4 grasses, and what will happen as Earth’s atmosphere and climate continue to change? This cross-disciplinary project will utilize precision sample preparation and in-situ analytical methods to characterize 1. the distribution of disseminated and occluded carbon in phytoliths, and 2. the carbon isotopic ratios of these reservoirs, reflecting photosynthetic pathway. The project will first compare leaf and phytolith chemistry of greenhouse-grown specimens and move on to soils with the ultimate goal of application to fossil systems. The proposed method, once fully developed, can be executed at many laboratories world-wide and will represent a major leap forward in analytical phytology. This work will have applications to a wide range of topics including the relationships between grassland and hominid evolution.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

草原覆盖了约40%的地球陆地表面，在陆地生命、全球气候和重要的人力资源中发挥着关键作用（禾本科包括所有谷类作物，如水稻和小麦）。虽然它们出现于7000万年前，但草原的扩张只开始于2200万年前，热带稀树草原生态系统出现于800万年前。草的进化和生态系统的变化可能与气候、景观和动物的进化相吻合。识别草化石的最好方法是通过微小的二氧化硅碎片（“植物岩”），当植物的其他部分分解后，它们被留在沉积岩中。植物岩具有特定草类的形状特征，但没有一种方法可以揭示产生它们的草的光合作用类型（C3或C4）。该项目测试了一种利用植物岩测量其内部未分解碳的化学成分的新方法；因此，产生它们的草的光合作用类型。这将使研究人员能够回答有关草原过去和可能的未来的问题。例如，最早的热带稀树草原上生长着什么草，它们利用什么光合作用？是什么导致了C4草的传播？随着地球大气和气候的持续变化，将会发生什么？这个跨学科项目将利用精确的样品制备和原位分析方法来表征1。2.植物岩中浸染和闭塞碳的分布；这些水库的碳同位素比值，反映了光合作用途径。该项目将首先比较温室生长标本的叶子和植物岩化学成分，然后转向土壤，最终目标是将其应用于化石系统。所提出的方法一旦得到充分发展，就可以在世界各地的许多实验室中执行，这将是分析生理学的一个重大飞跃。这项工作将应用于广泛的主题，包括草原和人类进化之间的关系。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。