Joseph A. Meyer

New Trends in the Studies About the Metabolism of Pesticides in Plants

During the past 15 years, many reviews have been published concerning the metabolism of pesticides in plants. They usually study the problem according to the different types of pesticides (Frear et al. 1972 a and b, Kearney 1975, Klein 1972, Kuhr 1976, Menn 1972, Naylor 1976, Sijpesteijn et al. 1976), or according to the different types of biochemical reactions which generate the degradation products (Baldwin 1977, Matsunaka 1972, Menn and Still 1977). These last times, more and more new types of pesticides are studied; these studies show that the previous generalizations frequently do not correspond to reality. The present work studies the factors which influence the biochemical pathways of pesticide metabolism, the rate of metabolism, and the possible phytosanitary and toxicological properties of the metabolites. This work is based on recent researches; it thus shows the new trends of the studies about pesticide metabolism in plants.

Metabolic Study of Tritium Labeled 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 [ 3 H]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 [ 3 H]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.