Minimization of 1-Methylcyclopropene Concentration to Regulate Cell Wall Metabolism of ‘Arisoo’ and ‘Picnic’ Apples in Cold Storage

Cell wall constituents and cell wall hydrolase (CWH) enzyme activities play crucial roles in extending the postharvest storability of apples. 1-Methylcyclopropene (1-MCP) has been extensively used to regulate cell wall metabolism of apples during storage. However, the consequences of 1-MCP can differ according to its concentration and the cultivar being treated. In this study, we investigated how 1-MCP concentrations (0.5 and 1.0 µL·L^-1) regulate the cell wall components and the activities of CWH in two new apple cultivars, ‘Arisoo’ and ‘Picnic’, during their cold storage. In 1-MCP-treated fruits, uronic acid (UAC) and total sugar contents (TSC) were significantly higher in ‘Arisoo’, but only UAC was significantly higher in ‘Picnic’, when compared with control fruits. 1-MCP significantly inhibited CWH activities in both cultivars. The results observed between 0.5 and 1.0 µL·L^-1 did not diverge obviously in ‘Arisoo’, however, 0.5 µL·L^-1 generated better results over 1.0 µL·L^-1 in ‘Picnic’. Conclusively, the results suggest that it is economically more appropriate to use 0.5 µL·L^-1 1-MCP to extend the postharvest storability of apples, especially ‘Arisoo’, because of its ability to delay the solubilization of fruit softening-related cell wall components and to suppress CWH enzyme activities.