RESPONSE OF DENDROBIUM 'PLANTY FUSHIA' TO ETHYLENE AND ETHYLENE INHIBITOR

Dendrobium is the second largest genus in the Orchidacea family that is used as cut flower. Some cultivars are sensitive or insensitive to ethylene, which can affect the vase life. 1-Methylcyclopropene (1-MCP) has been used as a postharvest treatment to inhibit ethylene response and extend the vase life. The objective of this research was to determine the effect of ethylene and 1-MCP applications on vase life of Dendrobium ‘Planty Fushia’, an ethylene sensitive cultivar. Inflorescences were dipped into ethephon, an ethylene-releasing compound, at 10 ppm for 5 min. before or after 1-MCP fumigation at 10 and 200 µl/L for 24 h and distilled water served as the control. Then, they were held in distilled water and stored at ambient temperature (22±2°C). Ethephon treatment significantly reduced the vase life, water uptake, membrane stability and percentage of open buds and also increased respiration rate, ethylene production, flower abscission and malondialdehyde (MDA) content. In addition, inflorescences fumigated with high concentration of 1-MCP before being dipped into ethephon showed a reduction effect of ethephon but had no significant difference with that of control. This result implies that using 1- MCP at 200 µl/L before shipping could reduce the effect of exogenous ethylene during export.