Biological and biochemical detection techniques for glufosinate

Abstract

Biological and biochemical methods, based on glufosinate inhibitory effects on plant growth and nitrogen metabolism, were examined for their applications to detect this herbicide. Dose-response analysis of radicle growth inhibition showed that, among six vegetables tested, Chinese mustard and edible amaranth were the most sensitive to glufosinate. Field mustard and cruciferous Ching-Geeng were found to be more sensitive to this herbicide than the other four vegetables when three-leaf-seedlings were tested in another bioassay. In three-leaf seedlings of Ching-Geeng, accumulation of ammonium, a biochemical marker for glufosinate toxicity because of its inhibition of glutamine synthetase, showed a linear regression to the log-transformed concentrations of glufosinate ranging from 7.5 X 10(-5) to 1.5 X 10(-3) M. For the detection of glufosinate lower than 7.5 X 10(-6) M, a linear regression was observed between ammonium accumulation and the applied concentration, instead of the log-trans- formed value, of glufosinate. A similar relationship was observed between the accumulation in Ching-Geeng seedlings of glyoxylate, another biochemical marker, and glufosinate but with a narrower range than that for ammonium accumulation. The applicability of ammonium accumulation in three-leaf seedlings of Ching-Geeng to detect glufosinate residue in water and soil was confirmed by high-performance liquid chromatography (HPLC)

Screening and Identification of Glufosinate-Degrading Bacteria from Glufosinate-Treated Soils

“…Soils of 0-to 15-cm depth sampled from 10 sites in each field were mixed thoroughly, air dried, and sieved through 2-mm pore, and then underwent pH, electric conductivity, total nitrogen (Bremner 1965), and available phosphate (Bray and Kurtz 1945) determinations ( Table 2). In addition, they were analyzed for glufosinate residue by high performance liquid chromatography (HPLC) 2 (Sancho et al 1996;Zhou and Wang 2006). The recovery rate of glufosinate from soil samples in this experiment averaged 93.1% with a standard error of 9.8%.…”