Changes in calcium level in apple cortex tissue shortly before harvest and during postharvest storage

During 3 consecutive years, occurrences of storage disorders of McIntosh apples (Malus domestica, Borkh.) increased with decreasing Ca concn in the outer cortical flesh at harvest. Time‐course studies showed that during maturation and storage of apples, Ca concn in the core region declined by about 50%. In the outer flesh, Ca concn declined during maturation, reached a minimum at or shortly following harvest, and then rose significantly during subsequent storage. Preharvest treatments increased Ca concentration in the outer flesh at harvest, and did not influence the rise in Ca following harvest.