Metabolism of isopropyl 3-chlorocarbanilate by soybean plants

Abstract

Root-treated soybean plants absorb, translocate, and metabolize 14C-labeled isopropyl 3-chlorocarbanilate (CIPC-14C or chlorpropham-14C). Polar products and insoluble residues are rapidly formed in the roots. Insoluble residues are not found in the shoots. Time-course experiments showed that CIPC was lost from the treating solution by volatilization. Pulse time-course experiments demonstrated a precursor-product relationship between CIPC, polar products, and insoluble residues. Polar metabolites are not translocated once they are formed in either root or shoot tissues. The radiocar-bon distribution patterns of phenyl-14C and isopropyl-14C labeled CIPC were identical in all comparative experiments. Polar metabolites and insoluble residues from plants treated with isopropyl-14C labeled CIPC were hydrolyzed and steam distilled. The isolated alcohol was identified as 2-propanol. All of the radiocarbon in the soluble metabolites was recovered as 2-propanol. These data demonstrate that the CIPC carbanilate bond was not cleaved and that the isopropyl group was not altered by the plant.

Uptake, Translocation, and Metabolism of Propham by Wheat(Triticum aestivum), Sugarbeet(Beta vulgaris), and Alfalfa(Medicago sativa)

“…The proposed pathway for the metabolism of propham in wheat, sugarbeet, and alfalfa ( Figure 2) is based upon the re sults obtained in the present investigation and other work con cerning plant metabolism of propham and chlorpropham (10,23,24,25,26,27,28,29). In all species propham and chlor propham were ring hydroxylated in either the ortho or para position and rapidly conjugated to form polar metabolites.…”

“…propham was removed from the root zone, only a small con centration of the radiolabel appeared in the newly emerging tissues (23). Still and Mansager (25) found that the parent herbicide was metabolized completely by all tissues of soybean.…”

“…This informa tion, however, neither coincides with the results of the work mentioned previously (25,28) nor the work on the metabo lism of chlorpropham (isopropyl w-chlorocarbanilate) in two other plant species. The major aglycones isolated from soy bean and cucumber were isopropyl-2-hydroxy-m-chlorocarbanilate (23,24) and isopropyl-4-hydroxy-w-chlorocarbanilate, respectively (27).…”

Metabolism of isopropyl-3-chlorocarbanilate by cucumber plants

“…The metabolism of isopropyl-3-chlorocarbanilate-14C (chlorpropham-14C) in the resistant crop plant, soybean, has been established and shown to have a precursor-product relationship between the parent herbicide, its polar metabolites, and the solid residual materials (Still and Mansager, 1971, 1972. In soybean, the polar metabolites were shown to be the O-glucosyl derivatives of isopropyl-2-hydroxy-5-chlorocarbanilate (2 -hydroxy chlorprophpm) and isopropyl-4-hydroxy-3-chlorocarbanilate (4hydroxychlorpropham).…”

Enzymatic Hydrolysis of Herbicides in Plants

“…The residual properties of picloram have been studied in a variety of soil types and climates (9). In general, picloram retention is greatest in soils of high or ganic matter (17,20); it leaches more rapidly in sandy soils than in clay soils (6, 17); its persistence in the soil is directly related to rainfall (8,10,18); and its degradation in soils follows mixed-order kinetics due to a concentra tion-dependent lag period (14,17,21). The degradation of picloram by plant and soil micro flora show a complete lack of first-generation breakdown products (22).…”