Closed Chamber System for Easily Measuring the Respiration Rate of Intact Fruits

We designed and constructed a light-shielding, closed fruit chamber system that can easily measure the respiration rate of intact fruits. Intact strawberries (Fragaria_ananassa Duch. cv. Fukuoka S6) were placed in the newly-developed system, and the change in CO2 concentration was measured. It was observed that this method was a valid means of determining the change in the CO2 concentration. Also, the respiration rate of the intact fruits could be evaluated appropriately by fitting a theoretical equation to the change in CO2 density for 180 s after closing the chamber measured by newly-developed system and obtaining the initial slope. This method was applied to intact strawberries at different ripening stages, and the effect of on the respiration rate was investigated. As the ripening stage progressed and the volume of fruits increased, the respiration rate per fruit at each ripening stage also significantly increased. However, there was no significant difference in the respiration rate per unit fruit volume at each ripening stage. These results suggest that newly-developed system is effective in measuring the respiration rate per fruit. This system would contribute to the comprehension of intact fruit respiration and photosynthate translocation to fruits.