With the aim of extending vase life of cut dahlia flowers, we investigated the postharvest characteristics of the flowers, our focus was on the role ofethylene on senescence and on treatments that have extended vase life of other flowers. Continuous exposure to ethylene at 2 or 10 HLL-1 significantly accelerated petal abscission in cut flower.Flowers continuousty immersed in 1 or 10 uLL-1 2-chloroethylphosphonic acid(CEPA) solution wilted earlier than those treated with distilled water(Dw) or 0.15gL i citric acid. Eth- ylene production from the ovary and ray petal was relatively high(4.5 and 0.9 nLg 1 fresh weighth, respectively) at harvest, but decreased gradually over 5 days. No remarkable increase in ethylene produc- tion was observed during senescence. Silver thiosulfate complex(STS), an inhibitor of ethylene action, did not extend the vase life of cut flowers, although a high silver concentration was detected in flower organs. In contrast, pulse treatment with 1-methylcyclopropene(1-McP) and dip treatment with 6- benzylaminopurine(BA) extended the vase life of florets, and BA was more effective than 1-MCP when the flowers were held in both Dw and CEPA.BA spray treatment extended vase life of cut Kokucho, "Kamakura' and'Michan' flowers. These results suggest that dahlia flower senescence is partially regulated by ethylene,and BA is more effective in delaying the senescence of cut dahlia flowers than ethylene action inhibitors.