ISHS Acta Horticulturae 1014: Proceedings of the International Plant Propagators Society - 2012
CALCIUM-RELATED PLANT PHYSIOLOGICAL DISORDERS© |
| Author: | N.J.J. Combrink |
| DOI: | 10.17660/ActaHortic.2013.1014.2 |
| Abstract:
Calcium (Ca) is dependent on xylem translocation; it moves with the transpiration stream and binds with polysaccharides to strengthen cell walls, needed to produce firm fruit tissue, good quality and a long shelf life. Calcium prevents cell wall degradation, “leaky” membranes and premature senescence. Calcium deficiency disorders include “brown fleck” and poor keeping quality of potatoes, weak flower stems, blackheart in celery, bitter pit in apple and bract necrosis in poinsettia. Blossom-end rot (BER) is a Ca-deficiency disorder affecting tomatoes, peppers and watermelons. High temperatures (>30°C), high radiation levels (>300 W•m-2 or >1400 J•cm-2 per day), or low RH values (<50%) may trigger the development of BER. Three strategies may be followed to limit Ca deficiencies: (1) Improve conditions that enhance the uptake of Ca. (2) Improve the allocation of Ca to sensitive organs by improving xylem flow to these organs. (3) Avoid excessive growth where Ca ions are used to neutralise organic acids and insoluble oxalates are formed. | |
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