1 Institute of Genetics and Physiology, Hebei Academy of Agriculture and Forestry Sciences, Shijiazhuang, China 2 Plant Genetic Engineering Center of Hebei Province, Shijiazhuang, China Effects of 1-methylcyclopropene on superficial scald and related metabolism in 'Wujiuxiang' pear during cold storage

Summary ‘Wujiuxiang’ (Pyrus bretschneideri R. × Pyrus communis L.) pear often suffers from superficial scald after a long-term of cold storage. In this study, harvested ‘Wujiuxiang’ pear fruits were fumigated with 1-methylcyclopropene (1-MCP) at concentrations of 0.5 μL/L and 1.0 μL/L and subsequently stored at low temperature (0 °C). The superficial scald index; flesh firmness; total soluble solids (TSS) content; respiration and ethylene production rates; relative membrane permeability; contents of α-farnesene, conjugated trienols (CTols) and hydrogen peroxide (H2O2); and activities of superoxide dismutase (SOD), catalase (CAT), ascorbate peroxidase (APX), and lipoxygenase (LOX) of the peel were investigated. The results showed that compared with control, 1-MCP reduced the index of superficial scald; maintained a higher firmness and a lower TSS content; inhibited the accumulation of H2O2, α-farnesene and conjugated trienols and the increase in cell membrane permeability; and maintained a higher activity of APX, SOD and CAT and a lower activity of LOX. These findings indicate that 1-MCP regulates the activities of H2O2-scavenging enzymes to inhibit the accumulation of H2O2 and thereby reduces cell membrane damage and inhibits the accumulation of conjugated trienols. Thus, 1-MCP could decrease the incidence of superficial scald in ‘Wujiuxiang’ pear.