The Responses of Oncidium Cut Flowers to Ethylene and 1-MCP

Abstract

The ethylene production by Oncidium 'Gower Ramsey' buds and florets and response to 1-methylcyclopropene (1-MCP) were investigated. Small flower buds produced little ethylene (0.12 nL g^(-1) hr^(-1)) and the production declined to being undetectable as the bud grew and became a floret. Ethylene production increased again as the floret began to senesce. A peak of ethylene production occurred (1.5 nL g^(-1) hr^(-1)) at the half senescent floret stage. The rises in ethylene production occurred after the start of floret senescence. Floret buds were more sensitive to exogenous ethylene than the floret, as it took 5 versus 7 days for senescence symptoms to appear at 0.03 nL mL^(-1) exogenous ethylene. The ethylene inhibitor, 1-MCP was effective in prolonging the vase life of both ethylene-treated and non-ethylene-treated cut sprays. When 1-MCP was applied again after 7 days to the same sprays, senescence symptom development was further delayed. Concentration of 1-MCP as low as 235 nL m^(-3) which was one fourth of the concentration recommended for commercial use extended vase life. Bud opening also increased following 1-MCP treatment in ethylene-treated sprays. No difference in response to 1-MCP treatment was found when the treatment was varied from 2 to 12 h and from 10℃ to 28℃. A treatment with 1-MCP was a useful tool to extend vase life of Oncidium cut flower sprays.