[61] Pesticides and lipid synthesis in plant membranes

This chapter presents studies using inhibitors likely to interfere with the metabolism of lipids biosynthetic processes, as well as the role of membranous lipids. Pesticides and the improvement of analytical methods have opened the way for in-depth studies whose global approach is now becoming specific. Various methods make it possible to take a global view of the action of pesticides on lipidic constituents. In a study described in the chapter, a methodology also revealed that the action of R-40244 caused the total amount of membranous lipids and the linolenic acid content to decrease in the stem of Lolium multiflorum (seven-day treatment). Thiocarbamate compounds (Diallate, EPTC, CDEC) also inhibit the incorporation of [1-14C]acetate in the cuticular lipids of pea leaf fragments during a 90-min treatment. The principle of these experiments is the rapid extraction of surface lipids by a CHCl3/methanol mixture (2:1, v/v) followed by counting the radioactivity of the extract. Separation of these lipids by thin-layer chromatography (silica gel G in benzene) shows a decrease in the radioactivity of alkanes and secondary alcohols.