Uptake, Translocation, and Metabolism of 3,4-Dichloroaniline in Soybean and Wheat Plants

Abstract

The roots of 13-day-old soybean ( Glycine max L.) and 7-day-old wheat ( Triticum aestivum L.) hydroponic plants were exposed to [14C]-3,4-dichloroaniline (1.0 and 0.4 mg/1 (6.2 and 2.5 μᴍ) , respectively) and harvested after 48/120 h (soybean) and 72 h (wheat). Both species metabolized the xenobiotic almost quantitatively to N-(β-D-glucopyranosyl)-3,4-dichloroaniline, N-malonyl-3,4-dichloroaniline, 6′-O-malonyl-N-(β-D-glucopyranosyl)-3,4-dichloroaniline and non-extractable residues. In the soybean experiments 58.8 (48 h) and 54.6% (120 h) of the applied radioactivity were found in the nutrient; this fraction consisted primarily of N-malonyl-3,4-dichloroaniline. 37.3/24.1% (48/120 h) were detected in the plants. In the soybeans, 36.2 and 52.7% (48/120 h) of the absorbed 14C were translocated, mainly into hypocotyls, primary and secondary leaves. After 120 h, the main metabolite was N-malonyl- 3,4-dichloroaniline (38.5% ); considerable levels of this metabolite accumulated in the primary and secondary leaves (10.4 and 10.4%). The glucosides were mainly found in the roots of the soybean plants. Totals of 23.5 and 35.1% (48/120 h) were transformed to non-extractable residues. In wheat, 78.3% of the applied 3,4-dichloroaniline was absorbed after 72 h. This fraction was partially translocated to the leaves, but most of the residues remained in the roots (90.3% of absorbed 14C). In wheat, a total of 45.6% was transformed to nonextractable residues. The soluble radioactivity in the roots consisted of nearly equal amounts of the glucosides and the N-malonyl conjugate. The processes observed in soybean and wheat roots resembled those of the respective cell suspension cultures published previously.