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Fruit Softening III. Requirement for Oxygen and pH Effects
Journal of Experimental Botany
Vol. 33, No. 137 (December 1982), pp. 1263-1269
Published by: Oxford University Press
Stable URL: http://www.jstor.org/stable/23690503
Page Count: 7
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The regulation of the softening of the cortical tissue of apple and pear fruits was investigated. Transfer of pear fruits to a nitrogen atmosphere arrested fruit softening and pectin degradation within 24 h. Anoxia also inhibited softening of discs cut from ripening pear fruits within 6 h, but polygalacturonase (EC 188.8.131.52) activity was not substantially impaired and pectin degradation continued as in air. Discs of apple tissue softened more slowly than pear but apple discs were firmer after 24 h under anoxia than in air. Softening of pear tissue could be reversed by infiltration with pH 8.0 buffer or calcium chloride solution up to day 3 of ripening at 18 °C. Buffer at pH 3.0 had no effect on fruit firmness but eliminated the effect of calcium in a combined treatment. A mixture of buffer at pH 8.0 and calcium chloride increased firmness more than either treatment alone. A similar reversal of softening could be achieved with apple fruit tissue after storage for 28 weeks.
Journal of Experimental Botany © 1982 Oxford University Press