Ethylene and postharvest performance of potted kalanchoe

The postharvest life of different cultivars of kalanchoe plants (Kalanchoe blossfeldiana Poelln.) varied widely. The display life of plants of 'Nadia' was much longer than that of plants of 'Debbie' (10 weeks compared with 7 weeks). During display life, senescing flowers were replaced by opening buds and the difference in display life was primarily a function of differences in life of the individual flowers in the inflorescences (approximately 45 and 20 days, respectively, for 'Nadia' and 'Debbie'). Approximately 8 h after the start of exposure to ethylene, kalanchoe flowers started to inroll, reaching a minimum diameter after exposure for 24 h. The effects of ethylene were somewhat reversed by returning the plants to air within the first 24 h of exposure. Thereafter the flowers wilted and senesced irreversibly. Ethylene sensitivity varied widely among cultivars; while flowers of 'Alexandra' lost 57% of their diameter in response to 1 mu l l(-1) ethylene treatment, flowers of 'Debbie' lost only 2%. Flowers of the new 'African Queen' series were particularly sensitive to ethylene. There was no clear relationship between ethylene sensitivity and postharvest life in the absence of ethylene although 'Nadia' had the longest display life of all tested cultivars, 'Nadia' flowers showed a 35% diameter reduction in response to treatment with 1 mu l l(-1) ethylene for 24 h. Treatment with 1-methylcyclopropene (1-MCP) had no effect on the normal life of kalanchoe plants, although 1-MCP has been shown to prevent the response of kalanchoe flowers to ethylene. (C) 2000 Published by Elsevier Science B.V. All rights reserved.