Absorption and translocation to fruit for cesium applied on apple tree leaf surface.

We investigated the behavior of stable Cs+ ions contained in droplets applied directly on the leaf surfaces of plumleaf crab apple trees (2-3 years old Malus domestica 'Alps Otome') at three different fruit growing stages: before bearing fruit, early fruit development and late fruit development stages. Most of the Cs was rapidly transferred from the leaf surfaces into the applied leaves after application, and then gradually transferred to the fruit through the branches. The mean proportion of Cs transferred to fruit by harvest time ranged from 11 to 30% not directly depending on the fruit growing stages. Cs absorption from leaf surfaces was faster at early and late fruit development stages than before bearing fruit stage, and Cs transfer from leaf surfaces to the fruit was faster as the fruit growing stage progressed. To describe the transfer of Cs, we constructed a compartment model using the datasets of obtained for each fruit growing stage. However, it did not well reproduce the measured values, showing that further studies are necessary.