Lurie, S., Department of Postharvest Science, Agricultural Research Organization, Volcani Center, Bet Dagan, Israel
Weksler, A., Department of Postharvest Science, Agricultural Research Organization, Volcani Center, Bet Dagan, Israel

1-Methylcyclopropene (1-MCP) is an ethylene action inhibitor which prevents plant tissue from perceiving and responding to ethylene. It is generally effective in concentrations of 1 micromolar or less, and can retard many ripening processes that depend on ethylene for their induction. These processes include softening, color development, loss of titratable acidity, and increase in volatile compounds. The active compound is a gas (as is ethylene) and the treatment is given after harvest. The effect of 1-MCP on apricots, nectarines, peaches and plums has been investigated. Apricots responded to 1-MCP by slowing their softening, peel color change and loss of titratable acidity. However, ethylene production and respiration were not affected, and the treatment with 1-MCP enhanced internal flesh browning. Peaches and nectarines responded to 1-MCP treatment in a similar manner to apricots by slower softening, color change and loss of titratable acidity, with only minor inhibition of ethylene production. However after storage, fruit which had received a 1-MCP treatment developed more flesh disorders, particularly bleeding, than untreated fruit. Japanese plums responded positively to 1-MCP. Ethylene production was inhibited, as was softening, color change and loss of titratable acidity. There were fewer storage disorders, such as internal browning and gel breakdown in 1-MCP treated fruit than non-treated fruit. The use of this compound can help to elucidate the role of ethylene in the development of physiological storage disorders and in regulation of ethylene biosynthesis in different types of stone fruit.