Effects of 1-MCP on reactive oxygen species, polyphenol oxidase activity, and cellular ultra-structure of core tissue in ‘Yali’ pear (Pyrus bretschneideri Rehd.) during Storage

1-methylcyclopropene (1-MCP) has been shown to delay fruit ripening and senescence during storage. In this study, we investigated the effects of 1.0 μL·L −1 1-MCP on the biochemical changes and cellular ultra-structure of the core tissue in ‘Yali’ pear ( Pyrus bretschneideri Rehd.) fruits stored at 25 ± 2°C. Our results showed that 1-MCP treatment significantly decreased the rates of respiration and ethylene production before their climacteric peaks, inhibited the development of core browning, lowered the chlorogenic acid content and polyphenol oxidase activity before the onset of core browning, and preserved high levels of superoxide dismutase activity, ascorbic acid, and glutathione contents. Furthermore, it suppressed the accumulation of hydrogen peroxide, superoxide anion, and malondialdehyde in the core tissue, maintained the integral structure of the cell membrane and organelle, and delayed the accumulation of electron-opaque matters in the vacuoles of core cells. These results suggested that 1-MCP treatment could reduce the injury caused by reactive oxygen, inhibit the oxidation of phenolics, and keep the cell membrane intact in core cells, thus, delaying the core browning in ‘Yali’ pear during storage.