HUMAN EMBRYO MR MICROSCOPY ATLAS

土壤固有的不透明性质使得对 地下的生物过程极其困难。传统型 方法包括物理挖掘和筛选土壤以及 人工观察表面的施加，例如与 根加速器和微型加速器。这些技术要么摧毁了 土壤中根部的几何形状，或通过强制 根沿着玻璃或塑料表面生长。东南部的许多土壤 美国的松树种植园是浅沙质壤土， 纹理与先前磁共振成像中使用的沙子样本相似 实验。磁共振方法的发展，以确定功能，活体 在土芯中的根将为 研究地下过程。根相对于的方向 X-Y平面尤其重要，因为大多数营养矿化 发生在土壤表层10厘米内。此外，还描述了 分枝模式将有助于研究根与根之间的关系 架构和养分可利用性。对这一概念的理解 地下碳通过根系生产分配的关系 而根的资源获取是当前一个很大的话题 对评估植物对全球变化的反应的兴趣，以及 森林为预测的高水平提供汇的潜力 二氧化碳的排放量。我建议开发成像协议，使用传统的 3-自旋回波技术，观察完整农田土壤中的活根 核心。将从美国农业部抽取有限数量的岩芯样本。 位于苏格兰郡的林业局站点，并拍摄了图像。然后，内核将 被解剖，并确定核心内的根。的情况 恢复的根段将被记录，并与 能够在MR图像集中检测到它们。岩心直径将 8厘米，完全在当前图像采集的大小范围内 协议。

The inherently opaque nature of soil has made the study of belowground biological processes extremely difficult. Traditional methods include physical excavation and sieving of soil as well as the imposition of artificial viewing surfaces such as are used with rhizotrons and minirhizotrons. These techniques either destroy the geometry of the roots within the soil, or create artifacts by forcing roots to grow along a glass or plastic surface. Many soils of the SE United States supporting pine plantations are light sandy loams, similar in texture to the sand samples used in previous MR imaging experiments. Development of MR methods to identify functional, living roots within soil cores would provide a powerful new tool for the study of belowground processes. The orientation of roots relative to the X-Y plane is especially important, as most nutrient mineralization occurs within the top 10 cm of soil. In addition, description of branching patterns will allow study of the relationship between root architecture and nutrient availability. Understanding of the relationship between belowground C allocation through root production and resource acquisition by roots is currently a topic of great interest in evaluating plant response to global change, and the potential for forests to provide a sink for predicted elevated levels of CO2. I propose to develop imaging protocols, using traditional 3-Dspin echo techniques, to view living roots within intact field soil cores. A limited number of cores will be sampled from the U.S.D.A. Forest Service site in Scotland County, and imaged. Cores will then be dissected, and roots within the core identified. Condition of the recovered root segments will be recorded, and correlated with the ability to detect them within the MR image sets. Core diameter will be 8 cm, well within the size range for current image acquisition protocols.