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Trace Chemical Detection through Vegetation Sentinels and Fluorescence Spectroscopy

Informally Refereed

Abstract

Detection of environmental contaminants through vegetation sentinels has long been a goal of remote sensing scientists. A promising technique that should be scalable to wide-area applications is the combined use of genetically modified vascular plants and fluorescence imaging. The ultimate goal of our research is to produce a bioreporter that will express fluorescence when encountering nitro-aromatic compounds such as munitions contaminants. To test the recovery of gfp, our study used tobacco plants (Nicotiana tabacum) that were genetically modified to express the m-gfp5-ER variant of the green fluorescent protein (gfp) in conductive tissues. Induction of the gfp was stimulated by the uptake and translocation of a systemic organo-phosphate pesticide. The first objective of the study was to detect the induced gfp emission in plants exposed to the pesticide. The second objective of this effort was to use a field spectrometer and imaging system to determine if the fluorescence signature (from the induced plants) was spectrally separable from negative controls and permanently expressing plants. Concurrent research is underway to optimize the induction specificity of the gfp for a variety of target materials (e.g., TNT, RDX, HMX). Here, we report results from a Phase I small-business technical transfer research grant (STTR) conducted in Edgefield, SC. Our tests showed that gfp could be detected by spectrofluormetry and laser imaging and that expressing plants produced approximately three times the fluorescence at 510 nm as the negative control. Correlation and agreement between the non-imaging and imaging spectrometer also showed the optimal excitation wavelength (gfp absorption maxima) to be between 390 nm and 410 nm. When matched with the emission wavelength, these numbers represent a broad Stoke’s shift of almost 100 nm that is optimal for gfp signal recovery.

Parent Publication

Keywords

monitoring, assessment, sustainability, Western Hemisphere, sustainable management, ecosystem resources, environmental contaminants, vegetation sentinels, fluorescence spectroscopy

Citation

Anderson, John E.; Fischer, Robert L.; Nelson, Jean D. 2006. Trace Chemical Detection through Vegetation Sentinels and Fluorescence Spectroscopy. In: Aguirre-Bravo, C.; Pellicane, Patrick J.; Burns, Denver P.; and Draggan, Sidney, Eds. 2006. Monitoring Science and Technology Symposium: Unifying Knowledge for Sustainability in the Western Hemisphere Proceedings RMRS-P-42CD. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station. p. 766-770
https://www.fs.usda.gov/research/treesearch/26570