Osservazioni sulle variazioni stagionali del contenuto di micro e macroelementi negli organi epigei delle pomacee: nota l.: melo « Golden Delicious »

Abstract

In this study, some observations on «Golden Delicious» apple tree variety are reported in order to evaluate annual changes of macroelements (N, P, K, Na, Mg) and microelements (Fe, Zn, Cu, Mg) in various tree organs such as flower-buds, flowers, fruits, leaves and shoots. In flower-buds, flowers and fruits, N, P, K total amount increased during growth season; while, the percentage of such mineral elements steadily increased until full-bloom and it decreased from fruit-setting till fruit-ripening. In flower-buds Ca totai amount was nearly constant, while in flowers and fruits higher levels were reached. On the contrary Ca percentage in the same organs decreased up to fruit ripening althougth higher levels were reached during flowering. Total N and P content in leaves increased, where in mature leaves the levels rcached a steady state. Potassium behaved similarly, but it reached the constant state with lower levels. On the contrary N, P and K concentration, as percentage of dry matter, decreased; then, in mature leaves N, P, K percentage resuited almost constant until leaf-fall. In the leaves an initial increase of Ca content, both as totale amount and percentage of dry matter was recorded, followed later by a steady state. The new shoots, at the beginning of their development weer rich in N, P, K; where in mature shoots significant changes were not observed. Traces of microelcments were recorded in all tree organs