Changes in Respiration Rate of Several Fruits during and after Vibration

Abstract

As a result of previous studies on tomato fruit, further examinations were carried out on the physiological response of fruits to limited levels of vibration. In this report, eggplant, apple, Japanese pear, satsuma mandarin (Citrus unshiu Marc.), natsumikan (C. natsudaidai Hayata) and grape fruits were used. The effect of vibration at 1G, 2G and 3G for 1 hour or 5 hours on the respiration rate was determined during and after vibration.
In general, the respiration rate increased rapidly from the beginning of vibration, and continued to increase during vibration. The rate also continued to increase for a period after vibration. The elevated respiration rate fell once, then showed a small rise, and returned gradually to the initial level.
When the vibration time was short, the increase in rate of respiration was proportional to the intensity of vibration. However, for the longer vibration time, the increase in the rate of respiration was lower at 3G than that at 1G. This observation seemed to suggest that some physiological disorder may have occurred in fruit exposed to the more intensive vibration exceeding the limited level of vibration for every fruit.
The respiration rate of eggplant and apple fruits seemed to be more sensitive to vibration than that of the others. The respiration rate of grape fruit harvested at earlier maturity was more sensitive to vibration than that of fruit harvested at later maturity.
In addition, changes in internal gas concentrations during vibration were determined in Japanese pear and tomato fruits vibrated at 1G and 3G for 5 hours. High levels of carbon dioxide and low levels of oxygen were detected in both fruits, and high levels of ethylene were detected in tomato fruit.