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.

草原覆盖了地球陆地表面的约 40%，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（禾本科包括水稻和小麦等所有谷类作物），尽管它们出现在约 7000 万年前，但它们的传播。草原仅在约 2200 万年前开始出现，热带稀树草原生态系统在约 800 万年前就已出现。草的进化和生态系统的变化可能与气候、景观和动物的演变同时发生。来自微小的二氧化硅碎片（“植硅体”），植物其余部分分解后留在沉积岩中，植硅体具有特定草类的形状特征，但没有方法可以揭示植物的光合作用类型（C3 或 C4）。该项目测试了一种使用植硅体来测量其内部未分解碳的化学成分的新方法；从而确定了产生它们的草的光合作用类型。将使研究人员能够回答有关草原的过去和可能的未来的问题，例如，最早的稀树草原上生长着什么草，它们利用什么光合作用导致了C4草的传播，以及地球的大气和气候会发生什么。这个跨学科项目将利用精密样品制备和原位分析方法来表征 1. 植硅体中弥散和吸留碳的分布，以及 2. 碳同位素该项目将首先比较温室种植样本的叶子和植硅体化学，最终目标是应用于化石系统。所提出的方法一旦完全开发出来，就可以在这项工作将应用于包括草原和原始人类进化之间的关系在内的广泛主题。该奖项反映了 NSF 的法定使命，并被认为是值得的。通过使用基金会的智力优势和更广泛的影响审查标准进行评估来获得支持。