Comparative study on characteristics of calcium nutrition under protected culture during nectarine fruit development

An experiment was conducted to study the changes in calcium concentrations in different parts of Shuguang nectarine(Prunus persica var.nectariana cv. Shuguang) trees in protected culture during fruit development and compared them with those not in protected culture.The results showed that: 1) During nectarine fruit development,calcium concentrations rose at first and then declined in the rind under protected culture,while that in the rind out of protected culture were inversed.The dynamics of calcium concentrations in the other parts of fruit under protected culture were similar to that out of protected culture.The calcium concentrations in flesh and peduncle all decreased during nectarine fruit development.Calcium concentration reached a peak at first and then declined in the stone of nectarine,but the calcium concentration in seeds fluctuated significantly in the later period of fruit development.The calcium concentrations in rind and flesh of nectarine under protected culture were smaller than those of nectarine out of protected culture.2) During nectarine fruit development,calcium contention in the leaves increased at first,and then kept more or less constant in the mature period either in or out of protected culture.Calcium concentrations in the shoots under protected culture increased at first and then decreased,but increased againand peaked at the mature stage.Calcium concentrations fluctuated significantly in the shoots out of protected culture and had three peaks.3) Calcium concentrations in the roots under protected culture had a steady trend,but the calcium concentration in the roots out of protected culture fluctuated significantly.4) During nectarine fruit development,calcium concentration in different parts of nectarine trees under protected culture were relatively lower than those out of protected culture at corresponding stages.