Inhibition of ethylene responses by 1-methylcyclopropene and 3-methylcyclopropene

3-Methylcyclopropene (3-MCP) binds to the ethylene receptor and blocks it f or several days, but concentrationswise is less effective than 1-methylcycl opropene (1-MCP). In diverse ethylene-responsive systems, including ripenin g of mature-green bananas (Musa sapientum L.), inhibition of growth in etio lated pea (Pisum sativum L.) seedlings, abscission of orange (Citrus sinens is L.) leaf explants and mung bean (Vigna radiata L.) leaves, and wilting o f campanula (Campanula carpatica) and kalanchoe (Kalanchoe blossfeldiana) f lorets, full inhibition of the ethylene response required higher concentrat ions of 3-MCP. Depending on the experimental system, the effective concentr ation of 3-MCP was from 5 to 10 times higher than that required for 1-MCP.