The metabolic fate of the plant growth regulator 2,3,5triiodobenzoic acid was determined in soil using 14C-carboxyllabeled 2,3,5-tri1odobenzoic acid. l-14C-2,3,5-Triiodobenzoic acid was degraded to 14C02 by the microflora in soil; no radioactive COX was evolved from sterilized soil. Following incubation of 1-I4C-2,3,5-triiodobenzoic acid in soil, unchanged 2,3,5-triiodobenzoic acid and three metabolites (2,5-diiodobenzoic acid, 3,5-diiodobenzoic acid, and one unknown) were recovered. Peak concentrations of 2,5-diiodobenzoic acid and 3,5-diiodobenzoic acid were 15-20 and 14-15%, respectively, at 8 weeks of incubation and decreased thereafter.
Keyphrases 0 2,3,5-Triiodobenzoic acid-microbial degradation in soil, identification of metabolites 0 2,5-and 3,5-Diiodobenzoic acids-formation from microbial degradation of 2,3,5-triiodobenzoic acid 0 Microbial degradation in soil-2,3,5-triiodobenzoic acid 0 Plant growth regulators-microbial degradation of 2,3,5-triiodobenzoic acid 2,3,5-Triiodobenzoic acid is used as a plant growth regulator on soybeans. It has been the subject of numerous metabolic fate studies in a variety of animals and plants. This note summarizes studies on the degradation of 2,3,5-triiodobenzoic acid by the microflora of soil.
EXPERIMENTAL
Apparatus-Four 50-nil. conical flasks were connected in series with glass tubes and rubber stoppers so that attachment to a vacuum source would create a slow rate of aeration through the flasks. The contents of the flasks, beginning at the source of air, were as follows: