Tuesday, June 19, 2007 - 9:35 AM
Detection of Low-Level Herbicide Exposure Using Metabolic Profiling.
Wendy K. Cecil, Daniel L. Mullendore, Franco Basile, and Stephen K. Herbert. University of Wyoming, Univ. of Wyoming, PO Box 6, Torrington, WY 82240
Improper herbicide application can cause lost productivity in non-target plants and lost income for growers. The current method for diagnosing herbicide injury is visual inspection by a trained expert. Visual diagnosis is accurate but not objective, from the perspective of non-experts, nor is it quantitative. Moreover, low-level herbicide exposure may cause lost productivity without visual symptoms. The goal of our study is to determine whether low-level herbicide exposure can be diagnosed and quantified using metabolic profiles of leaf samples. Leaves of sunflower were exposed to varying levels of glyphosate (Roundup Ultramax II) and then sampled after five days. Leaf samples were analyzed for amino acid profiles. Amino acid analysis using gas chromatography-mass spectrometry (GC-MS) has not yet proven diagnostic for glyphosate injury but analysis of total methanol-soluble metabolites separable by GC may allow different herbicides to be reliably distinguished in cases of low-level injury with ambiguous visual symptoms.