Foliar and radicular absorption of 65Zn and its redistribution in citrus plant

The objective of this work was to evaluate the contribution of the Zn applied on the leaves and on the soil to the organs gown after the placation. Orange trees 'Valencia' variety (Citrus sinensis (L.) Osbeck) budded on 'Swingle' citrumelo (Citrus paradisi Macfad. Cv. Duncan x Poncirus trifoliata (L.) Raf) were used in both experiments carried out in greenhouse. In the first experiment, five-year-old orange trees, grown in substrate, were sprayed with 80 mL/tree of a solution containing (ZnCl2)-Zn-65 in the concentration of 0.25 g L-1 Zn, when they were emitting flowering process. In the second experiment, five-year-old orange trees and young orange trees were grown on sandy soil. The (ZnSO4)-Zn-65 center dot 7H(2)O was applied in the young trees in the planting period, and in the orange trees with 5 years under coverage. After the emission of new growing fluxes, the vegetal material was collected, dried and submitted to nitroperchloric extraction. In the extract, both the total Zn and the Zn-65 in a solid scintillation were determinated. The foliar fertilization increased the content of Zn in leaves that had received the application. The Zn applied on the soil, both in the planting process and in the greenhouse, increased the Zn contents in the plant organs which developed after the application Index Terms: foliar application, soil fertility, micronutrients.