NEW VIEWS OF THE PREREQUISITES FOR AN OCCURRENCE OF BITTER PIT IN APPLE AND ITS CONTROL BY CALCIUM SPRAYS

M.C. Saure
Calcium sprays for the prevention of bitter pit in apple are based on the assumption that bitter pit is caused by calcium deficiency in the fruit. However, such sprays usually do not achieve more than at best a reduction of the disorder. An explanation for the limited and variable success is not available as yet. Here, the function of calcium sprays is reconsidered, proceeding on the hypothesis that bitter pit results from a deterioration of cell membranes under stress. It is proposed that the main prerequisite for the occurrence of bitter pit are high levels of endogenous gibberellins, resulting in an increased susceptibility to stress by directly increasing the permeability of the cell membranes and additionally interfering with the transport of calcium into the fruit. Calcium sprays would temporarily counteract the effects of gibberellins by stabilizing the cell membranes but not reduce the level of gibberellins. Whereas calcium sprays influence the situation only in individual fruits, alternative methods of bitter pit control act on the whole tree by either directly reducing gibberellin biosynthesis or promoting endogenous gibberellin antagonists, thus removing the main prerequisite for the occurrence of bitter pit.
Saure, M.C. (2002). NEW VIEWS OF THE PREREQUISITES FOR AN OCCURRENCE OF BITTER PIT IN APPLE AND ITS CONTROL BY CALCIUM SPRAYS. Acta Hortic. 594, 421-425
DOI: 10.17660/ActaHortic.2002.594.54
https://doi.org/10.17660/ActaHortic.2002.594.54
calcium deficiency, calcium transport, cell membranes, gibberellins, growth control, stress
English

Acta Horticulturae