Accumulation of calcium by ripening berries on grape (Vitis vinifera L. cv. Asgari)
Application of pre-harvest Ca sprays significantly increased Ca-berry content of table seedless grape 'Asgari'. Calcium sprays were made at rates of different concentrations: 0%, o.8%, 1.2%, 1.6% and 2% w/v CaCl2 (as: T0, T1, T2, T3, and T4). Applications were made at fruit set, early pre-bunch closure and late bunch closure. Calcium content per berry was assessed in all compartments of the fruit. Fruit analyses confirmed the absorption of topical calcium by the grapevine was not proportional to the levels of Ca application. The rate of Ca accumulation during berry development followed a typical sigmoid pattern in the berry of all treatments. The rate of Ca accumulation was dependant on both the growth phase and the level of Ca applied. The highest rate was recorded at 60 days after anthesis in the high Ca (T4) treatment. Ca accumulation in the berry stopped after 80 days after anthesis (beginning of veraison) in all treatments, while, Ca redistributed from flesh to skin during berry ripening. At the end of growing season, Ca content of rachis is almost 6 times greater than Ca content of berry in all treatments. Calcium accumulated mostly in the rachis and less in the flesh during grape berry development.