Metabolic study of tritium labelled triforine in Barley

Abstract

Barley was grown in an experimental field. At the growth stage J, the aerial part of the plants was sprayed with an aqueous emulsion of a mixture of triforine and [ 3H]triforine (uniformly labelled in the piperazine ring), using the recommended dose rate of about 240 g triforine/ha. Barley was harvested when ripe, and straw and grain were analysed separately. The radioactivity concentration was 20 times higher in straw than in grain. The methanol soluble radioactive residue contained low amounts of radioactive triforine, and of its radioactive metabolites: N-[(2,2,2-trichloro-l-(piperazin-l-yl) ethyl]formamide, iminodiacetic acid, glycine, and unidentified water soluble radioactive compounds. The bound radioactive residues (insoluble in methanol) of [ 3H]triforine in barley grain was mainly incorporated into the protein fraction (as radioactive amino acids), and into the starch fraction (as radioactive glucose). In straw, the bound radioactive residues were mainly incorporated into the hemicelluloses fraction (as radioactive monosaccharides). No free or bound piperazine was observed in barley grain or straw.