The effects of ethylene and the rate of ethylene production were studied in several orchid flowers. Orchid flowers showed a wide range of sensitivity to ethylene; Vanda ‘Miss Joaquim’ was most sensitive, Cattleya, Cymbidium and Paphiopedilum were less sensitive, while Dendrobium and Oncidium were not sensitive. Ethylene production in opened flowers was low, less than 1 nl/flower/h. In Cattleya, a peak in ethylene production was observed at the onset of senescence. Emasculated and/or pollinated flowers of Vanda, Cattleya and Paphiopedilum produced high levels of ethylene; Dendrobium did not react to these treatments in ethylene production.
The anionic silver-thiosulfate complex (STS) was partially inhibitory to ethylene production in emasculated Cymbidium flowers, but appeared to stimulate the process in pollinated flowers. It was, however, effective in decreasing anthocyanin synthesis in both emasculated and pollinated Cymbidium flowers. In Cattleya, aminoxyacetic acid (AOA) and STS had no effect on longevity of cut flowers.