Effets physiologiques de l'atrazine à doses sublétales sur Lemna minor L. IV. Influence sur la composition lipidique

Abstract

The lipids and the fatty acids of duck weed (Lemna minor L.), cultivated aseptically during 5, 10, or 15 days in mineral solution containing sublethal concentrations of atrazine (0.05 to 0.75 ppm), were analysed by thin-layer and gas–liquid chromatography. All concentrations of atrazine used, independently of age of plants, increased the total fatty acid content, except for 5-day plants at 0.50 and 0.75 ppm atrazine where a decrease in total fatty acids was observed. α-Linolenic acid content increased while linoleic acid content decreased. Sublethal concentrations of atrazine increased the percentage of monogalactosyldiacylglycerol compared with total phospholipids and total neutral lipids. Monogalactosyldiacylglycerol was the main lipid involved in the α-linolenic acid increase observed in the total fatty acids. The increase in α-linolenic acid and in monogalactosyldiacylglycerol in the presence of sublethal concentrations of atrazine is an indication that these treatments maintain intact and fully functional chloroplast membranes.