The Translocation of Sulphonamides in Higher Plants

Abstract

The uptake and translocation of sulphanilamide, sulphacetamide, sulphaguani-dine, sulphapyridine, sulphadiazine, sulphathiazole, and 4:4-diaminodiphenyl-sulphone by broad bean plants growing in water culture has been studied. After varying times of exposure to the compounds at 100/μg./ml., total sulphonamide present in the roots, stems, and leaves was determined in acid-hydrolysed macerates by diazotization and coupling of the primary amino group. These compounds were identified in the leaves of treated plants by paper chromatography. Accumulation of sulphonamide in the roots appears to be related simply to time, and the concentration of sulphonamide may, eventually, be far higher than that in the treating solution. Movement from the roots to the stems and leaves depends on transpiration. Sulphanilamide and the sulphone passed rapidly into the leaves; sulphacetamide, sulphapyridine, sulphadiazine, and sulphathiazole moved less rapidly. There was, however, a marked accumulation of sulphacetamide, sulphapyridine, sulphadiazine, sulphathiazole, and the sulphone in the roots. Sulphaguanidine was poorly absorbed from the treating solution.