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ENVIRONMENTAL IMPACTS : SOIL IMPACTS39. Reddy K.N. and Zablotowicz R.M. (2003) : Glyphosate-resistant soybeanresponse to various salts of glyphosate and glyphosate accumulation insoybean nodules. Weed Science 51 (4) : 496–502.A ûeld study was conducted during 2000 and 2001 at Stoneville, MS, to determinethe effects of isopropylamine, trimethylsulfonium (Tms), diammonium, andaminomethanamide dihydrogen tetraoxosulfate (Adt) salt formulations ofglyphosate on weed control, growth, chlorophyll content, nodulation, nitrogencontent, and grain yield in glyphosate-resistant soybean and to assess potentialglyphosate accumulation in soybean nodules. Glyphosate-Tms and glyphosate-Adt injured soybean, and visible injury ranged from 29 to 38% 2 d after latepostemergence (LPOST) application; however, soybean recovered by 14 d.Glyphosate formulations had no effect on chlorophyll content, root and shoot dryweight, or nodule number but reduced nodule biomass by 21 to 28% 14 d LPOST.Glyphosate levels in nodules from treated plants ranged from 39 to 147 ng g21(dry weight), and leghemoglobin content was reduced by as much as 10%. Controlof ûve predominant weed species 14 d after LPOST was . 83% with one applicationand . 96% with two applications regardless of the glyphosate salts used. Soybeanyields were generally higher with two applications than with one applicationregardless of glyphosate formulation. These results indicate that soybean injuryand inhibition of nodule development with certain glyphosate formulations canoccur, but soybean has the potential to recover from glyphosate stress.http://naldc.nal.usda.gov/download/48637/PDF40. Saxena D., Flores S. & Stotzky G. (2002) : Bt toxin is released in rootexudates from 12 transgenic corn hybrids representing threetransformation events. Soil Biology and Biochemistry 34: 133-137.Cry 1Ab Bt protein from 3 different transformation events was detected in rootexudates and rhizosphere of seedlings grown for 40 days in the lab and alsogrown in the field. Protein detection was achieved using Quickstix ELISA andbioassay (mortality was between 38 and 100%).41. King CA, Purcell LC and Vories ED. (2001) : Plant growth and nitrogenaseactivity of glyphosate-tolerant soybean in response to foliar glyphosateapplications. AgronomyJournal 93 (1), 179–186.Glyphosate [N-(phosphonomethyl) glycine] inhibits 5-enolpyruvylshikimate-3-phosphate synthase, EC 2.5.1.19 (EPSPS), thereby blocking aromatic aminoacid synthesis. While glyphosate-tolerant (GT) soybean [Glycine max (L.) Merr.]contains resistant EPSPS, the N 2-fixing symbiont in soybean rootnodules, Bradyrhizobium japonicum, does not contain a resistant enzyme, andglyphosate spray to GT soybean may interfere with the symbiotic relationship.Glyphosate-tolerant soybean was treated with glyphosate at several differentstages of development to evaluate N 2fixation, growth, and yield in a series of(175)