1-Methylcyclopropene alleviates peel browning of ‘Nanguo’ pears by regulating energy, antioxidant and lipid metabolisms after long term refrigeration

Abstract

Ripening of ‘Nanguo’ pears (Pyrus ussuriensis Maxim.) can be slowed down by cold storage, but the peel of fruit is prone to browning when they are returned to room temperature. In this study, effects of 1-methylcyclopropene (1-MCP) treatment on peel browning (PB) of ‘Nanguo’ pears, as well as on energy, antioxidant and lipid metabolisms, were investigated during shelf life after cold storage. 1-MCP treatment inhibited the occurrence of PB in ‘Nanguo’ pears during 15 d of shelf life at 20 °C. 1-MCP treated fruit showed higher firmness, glutathione (GSH) content, ATP concentration and energy charge (EC) value. Meanwhile, lower ethylene production and respiration rate, content of H2O2 and O2·−, glutathione disulphide (GSSG) content, as well as malondialdehyde (MDA) concentration and electrolyte leakage were detected in 1-MCP treated fruit. Activities and gene expression level of ATP synthase (ATPase), NADH dehydrogenase (NDA), vacuolar proton-inorganic pyrophosphatase (VPP) and glutathione peroxidase (GPX) were promoted by 1-MCP treatment. Activities and gene expression level of phospholipase D (PLD) and lipoxygenase (LOX) were inhibited by 1-MCP treatment. These results indicated that 1-MCP treatment could effectively alleviate PB in ‘Nanguo’ pears and the possible mechanisms were discussed.