Respiration of oranges and grapefruits harvested at different stages of development.

Young and unripe oranges and grapefruits stored at 15 degrees or 20 degrees evidenced shortly after harvest a marked increase in respiratory rate, and then a well-defined maximum which was followed by a decrease.Ethylene production by oranges (measured by the manometric method) was observed, with curves parallel to the respiratory curves.The respiratory upsurge was accompanied by color changes typical of maturity in the above fruits, and by abscission of stem-ends.When fruit was harvested close to or at commercial maturity, it evidenced a gradual respiration decrease without any upsurge. No ethylene production was detected in oranges of this stage.