Influence of Epicuticular Waxes on Foliar Absorption of Nitrate Ions by Apricot Leaf Disks

Abstract

The poor response of Prunus spp. to foliar nitrate sprays under field conditions (Leece and Kenworthy 1971) is not caused by an inability of Prunusleaves to meta-bolize nitrate ions (Leece, Dilley, and Kenworthy 1972). This is analogous to the response ofPrunus spp. to urea sprays (Dilley and Walker 1961a). Dilley and Walker (1961b) demonstrated that pretreatment of peach leaf disks by immersion in acetone to dissolve lipid components of the cuticle increased subsequent urea absorption. Bukovac (1965) found that lightly brushing the upper and lower surfaces of peach leaves with a camel-hair brush enhanced uptake of 3-chlorophenoxy-a-propionic acid by 22 and 34% respectively. Brushing was assumed to have partially removed or rearranged the epicuticular waxes.