The Respiratory Activity of Honeydew Melons During the Climacteric

Honeydew melons are climacteric fruits showing a typical risein respiration at the onset of ripening. Using tissue discsit is shown that at the time of the climacteric peak the majorpart of respiration is accounted for by the tissue adjacentto the internal cavity. Respiratory activity of tissue nearthe rind is not maximal until after the climacteric. The rateof oxygen uptake by tissue discs is increased by the additionof succinate and ADP indicating respiration to be limited bya shortage of substrate. Mitochondria are more active when isolatedfrom post- than from preclimacteric fruit, although the degreeof coupling of oxidative phosphorylation is similar in bothcases. Mitochondria are largely insensitive to cyanide.