Seasonal changes in calcium content in early and late peach cultivars

Seasonal calcium changes in peach [Prunuspersica (L.) Batsch] tree organs of a very early ('Flordastar') and a very late ('Tudia') fruit ripening cultivar were assessed during a growing season. Four two-year old potted trees grafted on seedlings rootstocks, trained to central leader, were destructively harvested at 5-week intervals and Ca content was determined in each organ separately. In 'Flordastar', Ca seasonal changes followed similar trends with a peak between March and April in taproot and coarse roots, whereas it increased linearly in fine roots and leaves. In 'Tudia', Ca followed a quadratic trend with a maximum in September in coarse roots, a polynomial trend with a maximum in August-September in shoots, and a quadratic increase in leaves. Fruit Ca decreased nonlinearly in both cultivars.