FOLIAR ABSORPTION OF ALUMINUM - STUDY ON FIXATION AND CUTICULAR PENETRATION OF ALUMINUM

Studies on the cuticular barrier have shown that aluminium is absorbed slightly by isolated cuticles from Prunus laurocerasus L. (0.7% at pH 4.3 and 0.37% at pH 1), with a low cuticle/water partition coefficien t: K-C/W=5.1 at pH 4.3 and K-C/W=2.8 at pH 1. The permeability of thes e cuticles is low, with a permeance to aluminium of P = 1.46 x 10(-9) ms(-1) at pH 4.3 and p=1.33 x 10(-9) ms(-1) at pH 1. Only a small effe ct of the extraction of cuticular waxes is observed, with a higher per meance of P-MX=3.03 x 10(-9) ms(-1) at pH 4.3 and P-MX=3.5 x 10(-9) ms (-1) at pH 1. This study reveals that for plants, the presence of Al o n the leaves is not of as great ecotoxicological importance as the con tent of soluble Al in the soil. Copyright (C) 1996 Elsevier Science B. V.