EN
The current knowledge of calcium nutrition of apple trees is reviewed. In spite of high calcium content in soils and high potential of calcium uptake by apple trees, calcium deficiency is a causal factor for many disorders in apple fruits. Apical meristems and young growing fruits with rapid cell division show a high demand for calcium and depend on its continuous supply. Concurrent with a change in fruit growth from cell division to cell expansion, the calcium intake to the fruits usually ceases and fruit calcium content may even decrease as a result of strong competition for calcium between leaves and fruits. Spraying of fruitlets with calcium, dipping and infiltration of fruits in calcium solution after their harvest may prolong the storage, decrease their sensitivity to physiological and pathological disorders, reduce respiration and ethylene production.