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United States Department of Agriculture

Agricultural Research Service

Research Project: Management Practices to Mitigate Global Climate Change, Enhance Bio-Energy Production, Increase Soil-C Stocks & Sustain Soil Productivity...

Location: Soil Plant Nutrient Research (SPNR)

Title: Design and operation of a continuous 13C and 15N labeling chamber for uniform or differential, metabolic and structural, plant tissue isotope labeling

Authors
item Soong, Jennifer -
item Reuss, Dan -
item Pinney, Colin -
item Boyack, Ty -
item Haddix, Michelle -
item Stewart, Catherine
item Cotrufo, M. Francesca -

Submitted to: Journal of Visualized Experiments
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 10, 2013
Publication Date: January 16, 2014
Repository URL: http://doi:10.3791/51117
Citation: Soong, J., Reuss, D., Pinney, C., Boyack, T., Haddix, M., Stewart, C.E., Cotrufo, M. 2014. Design and operation of a continuous 13C and 15N labeling chamber for uniform or differential, metabolic and structural, plant tissue isotope labeling. Journal of Visualized Experiments. doi:10.3791/51117.

Interpretive Summary: Tracing heavy stable isotopes from plant material through the ecosystem provides the most sensitive information about ecosystem processes; from CO2 fluxes and soil organic matter formation to small-scale stable-isotope biomarker probing. Isotope labeled plant material has been used in various studies of litter decomposition and soil organic matter formation1-4. From these and other studies, however, it has become apparent that structural components of plant material behave differently than metabolic components (i.e. leachable low molecular weight compounds) in terms of microbial utilization and long-term carbon storage5-7. We present the construction and operation of a continuous 13C and 15N labeling chamber. Representative results from growing Andropogon gerardii Kaw demonstrate the system’s ability to efficiently label plant material at the targeted levels. This chamber description represents a useful research tool to effectively produce uniformly or differentially multi-isotope labeled plant material for use in a myriad of experiments on ecosystem biogeochemical cycling.

Technical Abstract: Tracing heavy stable isotopes from plant material through the ecosystem provides the most sensitive information about ecosystem processes; from CO2 fluxes and soil organic matter formation to small-scale stable-isotope biomarker probing. Coupling multiple stable isotopes such as 13C with 15N, 18O or 2H has the potential to reveal even more information about complex stoichiometric relationships during biogeochemical transformations. Isotope labeled plant material has been used in various studies of litter decomposition and soil organic matter formation1-4. From these and other studies, however, it has become apparent that structural components of plant material behave differently than metabolic components (i.e. leachable low molecular weight compounds) in terms of microbial utilization and long-term carbon storage5-7. The ability to study structural and metabolic components separately provides a powerful new tool for advancing the forefront of ecosystem biogeochemical studies. Here we describe a method for producing 13C and 15N labeled plant material that is either uniformly labeled throughout the plant or differentially labeled in the structural and metabolic plant components. We present the construction and operation of a continuous 13C and 15N labeling chamber. Representative results from growing Andropogon gerardii Kaw demonstrate the system’s ability to efficiently label plant material at the targeted levels. Uniformly labeled plant material is produced by continuous labeling from seedling to harvest, while differential labeling is achieved by removing the growing plants from the chamber weeks prior to harvest. Challenges lie in maintaining proper temperature, humidity, CO2 concentration and light levels in an airtight 13C-CO2 atmosphere for successful plant productivity. This chamber description represents a useful research tool to effectively produce uniformly or differentially multi-isotope labeled plant material for use in a myriad of experiments on ecosystem biogeochemical cycling.

Last Modified: 8/21/2014
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