Respiratory metabolism and quality in postharvest sweet cherries (Prunus avium L.) in response to high CO2 treatment

The effects of high CO2 (5% and 10%), on respiratory metabolism and quality of sweet cherries ("Rainier" and "8-102" varieties), were evaluated following storage at 0 degrees C for 60 d. Quality (respiration rate, weight loss, firmness, etc.) in sweet cherries was significantly improved by high CO2 in storage. And high CO2 enhanced pentose phosphate pathway, decreased in the glycolytic pathway and tricarboxylic acid cycle in aerobic respiration proved by elevated the contents of NADP(H), source, and fructose, as well as alleviated the levels of NAD(H). Cell membrane integrity was also better in these conditions, with higher activities of pyruvate kinase, phosphofructokinase b, and adenosine triphosphatase and lower activities of polyphenol oxidases and cytochrome C oxidases. Moreover, high CO2 decreased anaerobic respiration by inhibiting the accumulations of pyruvic acid, ethanol, and acetaldehyde, as well as by reducing the activities of pyruvate decarboxylase and alcohol dehydrogenase. Novelty impact statement High CO2 (5% or 10%) enhanced the NAD(P)H levels in sweet cherries held at 0 degrees C for 60 d. Respiratory metabolism was higher following the use of 10% CO2 during such storage. High CO2 maintained cell membrane integrity in sweet cherries stored at 0 degrees C for 60 d.