IDBR: Development of a System for Measuring Dynamic Biological Responses in Plants using Coincidence Counting

该奖项旨在开发短寿命放射性同位素示踪仪器，以便在受控环境条件下实时跟踪活植物内部和植物之间的物质同化、转运和输出。环境控制下的放射性同位素示踪（RTEC）系统基于使用短寿命放射性同位素和伽马射线重合计数技术。在不需要高空间分辨率的应用中，重合计数是一种有效和经济的追踪放射性标记化合物积累的方法。该系统的实施将利用距离不到100米的植物生长设施和大学核实验室。该RTEC系统将用于提高对植物对环境变化的生理反应机制的理解。目前有9个研究小组参与了这项合作。拟议的仪器将提供检查环境变化对植物中碳(C)和氮(N)分配的动态影响的能力。特别是，RTEC系统将使研究人员能够在精确控制的环境条件下，对不同植物物种在植物-土壤界面和单个植物内的碳氮转运进行一些首次系统测量，这些信息将大大提高对植物碳固存控制的理解。RTEC系统支持的研究将补充研究二氧化碳浓度升高对植物生长影响的实地研究项目。该仪器将使测量能够潜在地揭示成熟树木明显缺乏长期碳固存的机制，这种机制已在全球正在进行的大规模自由空气二氧化碳富集实验中观察到。此外，该仪器将为以下主题的研究提供机会：养分吸收和分配的动力学（使用氮-13标记的营养物）、水分吸收和运输（在溶液中使用氟-18和氧-15标记的水）、植物生长中的碳氮平衡（使用氮-13标记的营养物和碳-11标记的二氧化碳），以及微生物活动在碳氮循环中的作用。除了科学上的好处外，该项目还将让研究生和本科生参与生物学和物理学的前沿跨学科研究。例如，生物学和物理学专业的本科生将帮助组装和测试伽马射线探测器，并将协助设计、组装和安装生长室中的探测器支撑结构。本科生还将设计、安装和测试二氧化碳研究中使用的气体循环回路，并进行整体系统测试。与两所地区历史悠久的黑人大学的物理教员的现有合作将鼓励他们使用这种研究仪器。

This award is for the development of short-lived radioisotope tracing instrumentation in order to track in real time the assimilation, translocation, and export of materials within and between living plants under controlled environmental conditions. The Radioisotope Tracing with Environmental Controls (RTEC) system is based on the use of short-lived radioisotopes and gamma-ray coincidence counting techniques. Coincidence counting is an efficient and economical method of tracing the accumulation of radioactively tagged compounds in applications where high spatial resolution is not required. The implementation of the system will utilize the plant growth facility and the nuclear laboratory at the university, which are less than 100 meters apart. This RTEC system will be used to improve the mechanistic understanding of plant physiological responses to environmental change. Nine research groups are currently involved in the collaboration. The proposed instrument will provide the capabilities for examining dynamic effects of environmental change on carbon (C) and nitrogen (N) allocation in plants. In particular, the RTEC system will enable researchers to make some of the first systematic measurements of carbon and nitrogen translocation in different plant species at the plant-soil interface and within single plants under precisely controlled environmental conditions, information that will dramatically improve understanding of the controls on plant carbon sequestration. The research enabled by the RTEC system will complement field research projects that study the effects of elevated CO2 levels on plant growth. This instrument will enable measurements that can potentially reveal the mechanisms responsible for the apparent lack of long-term carbon sequestration by mature trees that has been observed in large-scale Free Air Carbon Dioxide Enrichment experiments that are underway globally. In addition, this instrument will open opportunities for research on topics such as the dynamics of nutrient uptake and distribution (using Nitrogen-13 tagged nutrients), water absorption and transport (using both Fluorine-18 in solution and Oxygen-15 tagged water), the carbon-nitrogen balance in plant growth (using Nitrogen-13 tagged nutrients and Carbon-11 tagged CO2), and the role of microbial activities in the carbon-nitrogen cycle. In addition to its scientific benefits, this project will involve graduate and undergraduate students in frontier interdisciplinary research in biology and physics. For example, undergraduate biology and physics students will help with the assembly and testing of the gamma-ray detectors and will assist with the design, assembly and installation of the detector support structure in the growth chamber. Undergraduate students will also work on the design, installation and testing of the gas circulation loop used in the CO2 studies and with the overall system testing. Existing collaborations with physics faculty members at two regional historically black universities will encourage their use of this research instrumentation.