Cuticular Retention in Vitro and Localization of Zn after a Foliar Application of Zinc-containing Fungicides1

Abstract

Abstract The cuticular retention of zinc contained in 4 fungicides (Antracol, Calyram, M-Special, and Polyram Combi) and zinc chloride was studied using isolated pear leaf cuticles ( Pyrus communis L. cv. Passe Crassane). The retention of Zn by the cuticular discs was significant after a 24-hour immersion in each fungicide (0.2% w/v). The distribution coefficient, calculated as the ratio of the zinc retained by the cuticles (in μg/g) to the zinc content of the immersion liquid (in μg/ml), varied from 25.1 to 88.2 for the fungicides, but was only 5.7 in the case of ZnCl 2 . Laser probe mass spectrography indicated that Zn supplied with the fungicides remained superficially localized 24 hours after a foliar application on maize ( Zea mays L. cv. Dekalb 202); Zn was detectable only in the surface zone corresponding to a maximum depth of 30 μm from the adaxial leaf surface.