ABSTRACT
Physiological disorders, such as bitter pit in apple; blossom-end rot in tomato, watermelon, and pepper; tipburn in lettuce, cauliower, artichoke; and blackheart in celery are believed to be triggered by Ca2+ deciency and can strongly reduce crop quality and yield. These disorders are characterized by dark brown lesions on distal young and fast-growing tissue. In leafy vegetables, stunted growth and curling are also common symptoms. The conserved symptoms and factors leading to Ca2+ deciency disorders suggest the existence of conserved mechanisms regulating these disorders in fruits and vegetables. Suggested mechanisms triggering these disorders are involved in the inhibition of Ca2+ accumulation or abnormal regulation of cellular Ca2+ partitioning in affected tissues. Interactions between Ca2+ and other nutrients in affected tissue have also been suggested to be involved. Although recent ideas have suggested that oxidative stress may play an important role in Ca2+ deciency disorder development, they remain to be experimentally analyzed. Considering the complexity of Ca2+ deciency
C A L C I U M D E F I C I E N C Y D I S O R D E R S I N P L A N T S
disorders, control strategies should rst identify the genetic and environmental factors triggering mechanisms leading to symptom development. Based on the factors involved, specic approaches can be identied to effectively inhibit Ca2+ deciency disorder development.
