INHIBITION OF ETHYLENE BIOSYNTHESIS AND ACTION IN CUT CARNATIONS (DIANTHUS-CARYOPHYLLUS L) BY AMINOTRIAZOLE

Treating 'Elliott's White' cut carnations with 50 or 100 mM aminotriaz ole for 4 days inhibits the respiratory climacteric and significantly extends vase life. Aminotriazole induced time- and concentration-depen dent inhibition of ethylene evolution and onset of the ethylene climac teric by inhibiting ACC synthase activity. Flowers treated with 50 or 100 mM aminotriazole for 2 days exhibited concentration-dependent incr eases in ethylene evolution, respiratory activity, ACC synthase activi ty, and petal ACC content in response to the application of exogenous ethylene at 10 mu l.liter(-1). Senescence-assoclated morphological cha nges, increased ACC synthase activity, ACC content, and ethylene evolu tion were completely inhibited in flowers treated for 4 days with 100 mM aminotriazole. Although treatment with 50 mM aminotriazole for 4 da ys did not completely inhibit components of the ethylene biosynthetic pathway, no morphological or respiratory responses to the application of exogenous ethylene at 10 mu l.liter(-1) were observed, a result ind icating that prolonged aminotriazole treatment inhibited ethylene acti on. Chemical names used: (3)-1H-amino-1,2,4-triazole-1-yl (aminotriazo le), 1-aminocyclopropane-1-carboxylic acid (ACC).