P. Duque et Jd. Arrabaca, Respiratory metabolism during cold storage of apple fruit. II. Alternativeoxidase is induced at the climacteric, PHYSL PLANT, 107(1), 1999, pp. 24-31
Changes in mitochondrial respiration were investigated during cold storage
of apple fruit (Malus domestica Borkh. cv. Reinette du Canada). Postharvest
calcium treatment of the apples had no effect on the aspects of mitochondr
ial metabolism studied, suggesting that the role of calcium in fruit ripeni
ng is not related to respiration. it transient increase in mitochondrial ox
idative capacity occurred during storage around day 80 after harvest. This
climacteric burst was associated with an enhanced capacity of the alternati
ve pathway, but not of the cytochrome pathway. The major factor determining
this rise in alternative pathway capacity at the climacteric was the trans
ient increase in the amount of alternative oxidase (AOX) protein. Antibodie
s raised against the Sauromatum guttatum enzyme recognized a reduced form p
roduct of approximately 37 kDa and a 67-kDa band corresponding to the oxidi
zed form of the protein. During cold storage of the apple fruit, alternativ
e pathway capacity correlated with the levels of the AOX and was apparently
not dependent on major changes in the oxidation state of the enzyme. This
is the first work to report that the respiratory climacteric and the induct
ion of AOX are tightly and temporally linked.