0.2% Ca(NO_3)_2 solution was sprayed on Red Fuji apple respectively at 30 d after full flowering,40,33 and 26 d before harvest,and water spraying as the control.Changes of fruit firmness,TSS,β-galactosidase activity and pectin content during cold storage were studied.The results showed that calcium spraying could effectively decrease the β-galactosidase activity after storage,restrain the degradation of protopectin and the increase of water-soluble pectin,and keep the higher fruit firmness during storage of...