Oxygen Consumption by Fruits and Vegetables

Respiration by fruits and vegetables is vital action to generating the ATP needed for maintenance of cell viability, even after harvesting and as nutrients decompose. Therefore, respiration is strongly associated with qualitative deterioration during transportation and storage. Measurement and mathematical modeling of O-2 uptake and CO2 production rates have been effective for evaluating the deterioration rate of horticultural products. ATP is produced by FOF1-ATP synthase through the transfer of electrons from ubiquinone to cytochrome c oxidase (COX) in plant cells. Although COX consumes a large amount of O-2 taken into cells, oxidizing protons as the terminal enzyme in the classical electron transport chain, an alternative pathway involving an alternative oxidase has been discovered, which performs the same reaction in plant cells without producing ATP. Staining and light sensing have been employed to measure enzymatic activity and O-2 consumption rate, respectively.