Changes in respiration and ethylene production of apples in response to internal and external oxygen partial pressures

• Published in: Postharvest biology and technology 1996-12, Vol.9 (3), p.297-309
• Main Authors: Dadzie, Benjamin K., Banks, Nigel H., Cleland, Donald J., Hewett, Errol W.
• Format: Article
• Language: English
• Subjects: almacenamiento atmosfera controlada; Anaerobic compensation point; apples; cell respiration; controlled atmosphere storage; ethylene production; Malus domestica Borkh; manzana; Michaelis-Menten constant; oxigeno; oxygen; oxygene; Partial pressure difference; peel; pelure; piel vegetal; pomme; produccion de etileno; production d' ethylene; respiracion celular; respiration cellulaire; Skin permeance to gas; stockage en atmosphere controlee
• ISSN: 0925-5214; 1873-2356
• DOI: 10.1016/S0925-5214(96)00030-0

Variations in respiration rate and ethylene production of ‘Cox's Orange Pippin’ and ‘Granny Smith’ apples in response to reduced oxygen partial pressures were characterised by studying O 2, CO 2 and C 2H 4 partial pressure differences between the internal and external atmospheres (Δ p O 2 , Δ p CO 2 and Δ p C 2 H 4, Pa) of individual fruit maintained in different O 2 atmospheres at 20 ± 1°C. Δ p O 2 decreased at low O 2 levels, reflecting the decreased rate of O 2 uptake in low O 2 partial pressures. Oxygen uptake relative to that in air ( relr O 2 ) approximately followed Michaelis-Menten kinetics, with a half-maximal rate at 3.3 kPa O 2 for internal oxygen ( p i O 2 ) and 10.4 kPa O 2 for external oxygen ( p e O 2 ). An equation was developed to describe aerobic and anaerobic components of CO 2 production relative to that in air ( relr CO 2 ) as a function of p e O 2 or p i O 2 . The relationship between rate of C 2H 4 production relative to that in air ( relr C 2 H 4) and p i O 2 was reasonably described by a Michaelis-Menten type hyperbolic curve, confirming the expectation that small changes in O 2 partial pressure would have a much greater effect on relr C 2 H 4 at low p i O 2 than they do at high p i O 2 . In contrast, presence of the skin as a diffusion barrier resulted in development of an apparent ‘lag phase’ in the relationship between relr C 2 H 4 and p e O 2 such that it became essentially sigmoidal. These differences are attributed to differences in O 2 partial pressure between internal and external atmospheres.