Extractability of Calcium from Apple Fruit and Apple Leaf Tissue and the Occurrence of Bitter Pit

Abstract

SummaryA method was developed to extract calcium from carefully sampled apples of the same diameter (7·00±0·15 cm) and leaves using solutions of different extraction strength. The correlation between the extracted quantities of Ca from these tissues and the occurrence of bitter pit was no better than the correlation between total Ca and the incidence of bitter pit. Bitter pit was significantly correlated (r=0-92) with both the K/Ca ratio and the (K+Mg)/Ca ratio (both in equivalents). The correlation coefficients for the relationships between bitter pit and the extracted quantities of Ca, total Ca, K/Ca and (K+Mg)/Ca in fruit tissue were much higher than those derived from leaf tissue.