Effets physiologiques de la benzyladénine sur Lemna minor I. Influence sur la composition lipidique

Abstract

Doses from 0.002 to 2.0 ppm of benzyladenine (BA) increased the water content in 15-day-old plants of Lemna minor L. However, a concentration of 5.0 ppm decreased it. The total esterified fatty acid content increased up to 2.0 ppm and decreased at 5.0 ppm, compared with controls. The BA increased the percentages of total palmitic and α-linolenic acids and decreased the percentage of total linoleic acid, mainly for higher doses. At 2.0 and 5.0 ppm of BA, the proportions of phospholipids increased strongly as compared with galactolipids (especially the diacylgalactosylglycerol) and total neutral lipids. In phosphatidylcholine, phosphatidylethanolamine, and phosphotidylinositol, the α-linolenic acid content exhibited a marked increase at the expense of linoleic acid of these phospholipids. The percentage of α-linolenic acid in diacylgalactosylglycerol remained constant in the presence of BA, but it decreased in diacyldigalactosylglycerol. At concentrations of 2.0 and 5.0 ppm, the α-linolenic acid content of total neutral lipids increased greatly. The modifications observed in the lipid composition of L. minor, at 2.0 and 5.0 ppm in BA, suggest that the cell membranes (particularly those of chloroplasts) and their functions may be altered by these high doses of cytokinin.