Biotransformation of [ring‐U‐14C]atrazine to dealkylated and hydroxylated metabolites in cell‐suspension cultures

Abstract

SummaryThe biconversion of [14C]atrazine to deaikyt‐ated and hydroxylated products was studied in heteroirophic cell‐suspension cultures of carrot (Daucus caroia L.), Agrostemma githago L. (corn cockle). Digitalis purpurea L. (purple foxglove), soyabean (Giycine max L. Merr; four different cultivars). Datura stramonium L. (thorn‐apple) and wheat (Tritician aestivum L.). During 48 h of incubation, the herbicide was biotransformed by all species; turnovers yields differed considerably and were between 10.1% and 88.0% of applied 14C. Differences were also observed among the soyabean cultivars (10.1‐73.5%). Hydroxy‐atrazine, de‐ethyl‐, deisopropyl‐ and de‐ethyt‐deisopropylatrazine formed in the cultures were identified by thin‐layer chromatography (tlc) (co‐chromatography with reference compounds); deaikyiated metabolites were also proved by gas chromatography–mass spectrometry (gc–ms). In addition, highly polar transformation products emerged that were not identified. Portions of non‐extractable residues were below 5% (one soyabean cultivar: 8.9%). Atrazine was metabolized by the cells, mainly to its dealkylated derivatives and hydroxyatrazine (totals of 9.4‐54, 5%), whereas portions of highly polar products were lower (0.1‐26.1%). Exceptions were A. githago (26.0 and 33.6%, respectively) and D, purpurea (4.5 and 25.2% respectively). Thus, plants generally contribute to the environmental degradation of atrazine.