Porat, R., The Kennedy-Leigh Centre for Horticultural Research, Faculty of Agriculture, The Hebrew University of Jerusalem, P.O. Box 12, Rehovot 76-100, Israel
Shlomo, E., The Kennedy-Leigh Centre for Horticultural Research, Faculty of Agriculture, The Hebrew University of Jerusalem, P.O. Box 12, Rehovot 76-100, Israel
Serek, M., The Royal Veterinary and Agricultural University, Department of Agricultural Sciences, Section for Horticulture, Rolighedsvej 23, 1958 Frederiksberg C, Denmark
Sisler, E.C., Department of Biochemistry, North Carolina State University, Raleigh, NC 27695, United States
Borochov, A., The Kennedy-Leigh Centre for Horticultural Research, Faculty of Agriculture, The Hebrew University of Jerusalem, P.O. Box 12, Rehovot 76-100, Israel

Phlox (Phlox paniculata cv. Rembrandt) flowers were found to be very sensitive to ethylene. Exposure to ethylene enhanced flower abscission in a concentration-dependent manner, with 50% abscission attained after treatment with 1 μl l-1 ethylene for 12 h. As a result, ethylene also reduced the number of open flowers on the stems throughout their vase life. A 6-h pre-treatment with a volatile inhibitor of ethylene action, 1-methylcyclopropene (1-MCP), completely inhibited the ethylene-induced flower abscission and hence the reduction in the number of open flowers on the stems. 1-MCP was maximally effective in inhibiting the ethylene response at a low concentration (25 nl l-1) and had no visible toxic effects, even at 500 nl l-1. The effects of 1-MCP on flower abscission were comparable to that of a pulse treatment with silver thiosulfate (STS). We therefore suggest that it may serve as an alternative to the commercial treatment of phlox flowers with STS, the latter being an environmental hazard. © 1995.