Postharvest Biology and Technology 18 (2000) 43 – 48 Ethylene and postharvest performance of potted kalanchoe ¨ Margrethe Serek *, Michael S. Reid 1 Department of Agricultural Sciences, Horticulture, The Royal Veterinary and Agricultural Uniersity, Thoraldsensej 57, 1871 Frederiksberg C, Denmark Received 14 May 1999; accepted 9 August 1999 Abstract 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 ll -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 ll -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. © 2000 Published by Elsevier Science B.V. All rights reserved. Keywords: Ethylene; Kalanchoe ¨ blossfeldiana ; 1-MCP; 1-Methylcyclopropene; Postharvest www.elsevier.com/locate/postharvbio 1. Introduction Among potted flowering plants, kalanchoe ¨s (Kalanchoe ¨ blossfeldiana Poelln.) have long been known for their sensitivity to ethylene. Marousky and Harbaugh (1979) demonstrated that concen- trations of ethylene as low as 0.5 ll -1 would cause the flowers to inroll, destroying the orna- mental value of the plant. In ethylene-contami- nated environments, such as supermarkets, or the homes of smokers, kalanchoe ¨ plants therefore lose quality very quickly. Although we have shown that treatment with inhibitors of ethylene action will prevent these ethylene effects (Serek et al., 1994), few kalanchoe ¨ growers use these chemicals to increase the postharvest quality of their crop. * Corresponding author. Tel.: +45-35283406; fax: +45- 35283400. E-mail address: margrethe.serek@agsci.kvl.dk (M. Serek) 1 On leave from the Department of Environmental Horticul- ture, University of California, Davis, CA 95616, USA. 0925-5214/00/$ - see front matter © 2000 Published by Elsevier Science B.V. All rights reserved. PII:S0925-5214(99)00055-1