Reassessment of the role of calcium in development of bitter pit in apple.
Saure, M. C.;
Australian Journal of Plant Physiology Year: 1996 Vol: 23 Issue: 3 Pages: 237-243 Ref: 88 ref.
1996
บทคัดย่อ
From an extensive evaluation of the literature on effects of orchard factors on bitter pit development, the following hypothesis is derived: that the primary factor causing bitter pit is high gibberellin (GA) concentrations late in the season, probably resulting from excessive root activity. The increased GA concentrations may cause increased permeability of cell membranes in the fruits close to vascular bundles, thereby resulting in increased sensitivity of the fruit cells to postharvest water stress. Water stress, especially after harvest, may trigger the mechanism of bitter pit development if the primary factor establishing susceptibility prevails over factors that reduce susceptibility. Calcium deficiency could be a secondary factor, increasing an existing risk of bitter pit development. Ca2+ may stabilize the cell membranes and reduce their permeability. However, high GA concentrations may hamper its movements to the fruits. Externally applied growth retardants, or ripening-related endogeno
us GA antagonists in the fruit flesh (e.g. ethylene and abscisic acid), could also reduce susceptibility to bitter pit, independently of Ca2+, by antagonizing the GA effect. The limitations of present systems which use Ca2+ content of the apple fruit to predict bitter pit may reflect the secondary function of Ca2+ in bitter pit development.