SEASONAL-CHANGES IN THE COMPOSITION, DISTRIBUTION AND ACCUMULATION OF MINERAL NUTRIENTS IN PERSIMMON FRUIT

Changes in the concentration and quantities of macro- and micronutrients in fruit of persimmon (Diospyros kaki cultivar 'Fuyu') were recorded over two seasons in a commercial orchard. In one of the seasons, the nutrient distribution in tissues from basal, median and distal segments of the fruit was examined. The concentration of all nutrients in fruit (skin, flesh and seeds inclusive) declined during growth. Concentrations of Ca, Cu and Fe in skin were consistently greater, and those of P and S consistently smaller than corresponding concentrations in flesh throughout the season. Concentrations of B, K, N, Mg, Mn and Zn in flesh only exceeded those in skin during early fruit development. In tissues of mature fruit, the highest concentrations were found in seeds for all nutrients except Ca, which was more concentrated in skin. Significant differences between concentrations in the basal and distal ends of fruit were found for Ca, K and N. These differences were present as early as 9 weeks after fruitset, and in the case of K, were time dependent. The quantity of all nutrients accumulated by fruit tended to increase steadily throughout fruit development, the pattern of accumulation for N, Cu and Fe showing a seasonal dependence. For most elements, nutrient accumulation was strongly associated with increase in dry matter. For Ca, there was significant accumulation during early growth, so that by 12 weeks after pollination, approximately 88% of the final content had been acquired, as opposed to only 35% of the ultimate fruit dry mass. These results are discussed in relation to the composition and accumulation characteristics of other fruits. © 1990.