The relationship between 1-aminocyclopropane-1-carboxylic acid content in pollinia, ethylene production and senescence of pollinated Dendrobium orchid flowers

1-Aminocyclopropane-1-carboxylic acid (ACC) content in pollinia of Dendrobium Caesar 2N, Dendrobium Jew Yuay Tew, Dendrobium Pompadour, Dendrobium Sabin, Dendrobium Sonia Bom No. 28 and Dendrobium Waiter Oumae Taba 4N orchid flowers ranged from 70.0 nmol g(-1) for Dendrobium Pompadour to 76.2 nmol g(-1) for Dendrobium Jew Yuay Tew, and from 0.05 nmol pollinia(-1) for Dendrobium Caesar 2N to 0.14 nmol pollinia(-1) for Dendrobium Jew Yuay Tew. Ethylene production and senescence of cross-pollinated flowers of Dendrobium Pompadour correlated with the ACC content of pollinia. Greater ACC content in pollinia promoted a higher rate of ethylene production and induced earlier senescence of cross-pollinated flowers than cross-pollinated flowers by pollinia with a lower ACC content. The rapid rise of ethylene production in pollinated flowers was reduced by prior application of aminooxyacetic acid (AOA), an inhibitor of ACC synthase. ACC application rapidly increased ethylene production by non-pollinated Flowers.