Osservazioni sulle variazioni stagionali del contenuto di micro e macroelementi negli organi epigei delle pomacce: nota 2.: pero «Coscia»

Some observations were conducted on «Coscia» pear tree variety, in order to evaluate annual changes of N, P, K, Ca, Na, Mg and micro-elements such as Fe, Zn, Cu, Mn in various tree organs (flowers-buds, flowers and fruits, leaves and shoots). In flower-buds, flowers and fruits, total amount of N, P and K increased progressively through out growth season. On the contrary N, P, K contents in these organs, as percentage of dry matter, increased until full bloom, then they dropped rapidly from fruit-setting to fruit ripening. In flower-buds, Ca total amount was near1y constant; while the Ca total content in flowers and fruits increased until fruit ripening. Ca percentage in the same organs decreased during the same period, but during the blossom time the levels were high again. Total N, P, K and Ca leaf content steadily increased until summer, then it became constant and no further changes occurred until leaf-fall. On the other hand N, P and K leaf content, as percentage of dry matter, decreased during the same period; but in mature leaves it became constant. As far as the Ca and Mg percentage is concerned an increase was recorded during all growth season. The new shoots at the beginning of their development were very rich in N, P, K. In mature shoots a decrease was recorded from bloom period to summer time, while higher levels were reached in winter time. Traces of microelements were recorded in all tree organs.