Abstract The effects of 1-methylcyclopropene (1-MCP) treatment and controlled-atmosphere (CA) storage and their combination on quality and antioxidant capacity of postharvest blueberries were evaluated here. To investigate the most appropriate approach for maintaining fruit quality, blueberries were subjected to four different treatments, a control (CK), 1-MCP, 3% O2 + 10% CO2 (CA), and 1-MCP combined with 3% O2+10% CO2 (1-MCP + CA), then stored for 80 days at 0 °C. It was found that the applications of 1-MCP, CA and 1-MCP + CA were effective at delaying the increase in weight loss and inhibiting the decrease in firmness, total soluble solids (TSS) contents and titratable acidity (TA) contents. In addition, 1-MCP, CA and 1-MCP + CA treatment could significantly suppress MDA accumulation and relative electrolytic leakage promotion. Moreover, the production of reactive oxygen species (ROS), such as O2- and H2O2, was reduced by all the treatment, which was associated with increased activities of antioxidant enzymes including superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX). Taken together, our findings indicate 1-MCP, CA and 1-MCP + CA have potential applications in maintaining the quality and improving the antioxidant capacity of harvested blueberries, and 1-MCP + CA is the most effective treatment.

Abstract Pitaya fruits have high senescence rates throughout their postharvest storage period. Additionally, studies have confirmed that melatonin plays a regulatory role in plant senescence. However, the involvement of melatonin in the postharvest senescence of fruits remains unclear. In this study, two cultivars of pitaya fruit, ‘Zihonglong’ and ‘Jinghonglong’, were treated with melatonin and then evaluated for characteristics of senescence while in storage for 10 days. The results showed that melatonin treatment delayed fruit senescence in both pitaya cultivars, as indicated by the inhibition of weight loss, decay incidence, relative membrane permeability, and malondialdehyde (MDA) content, as well as the maintenance of the total soluble solids and ascorbic acid contents and the reduced respiration intensity. In addition, melatonin treatment reduced the O2·- production rates, H2O2 contents, and lipoxygenase activities but enhanced the activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX) in both pitaya cultivars. These results indicate that melatonin may contribute to delaying senescence in pitaya fruits. This study shows the potential of the use of melatonin in the postharvest storage of pitaya fruits, as well as other horticultural fruits.