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Steven A. Altman and Theophanes Solomos

Treating `Elliott's White' cut carnations with 50 or 100 mm aminotriazole for 4 days inhibits the respiratory climacteric and significantly extends vase life. Aminotriazole induced time- and concentration-dependent inhibition of ethylene evolution and onset of the ethylene climacteric by inhibiting ACC synthase activity. Flowers treated with 50 or 100 mm aminotriazole for 2 days exhibited concentration-dependent increases in ethylene evolution, respiratory activity, ACC synthase activity, and petal ACC content in response to the application of exogenous ethylene at 10 μl·liter-1. Senescence-associated morphological changes, increased ACC synthase activity, ACC content, and ethylene evolution were completely inhibited in flowers treated for 4 days with 100 mm aminotriazole. Although treatment with 50 mm aminotriazole for 4 days did not completely inhibit components of the ethylene biosynthetic pathway, no morphological or respiratory responses to the application of exogenous ethylene at 10 μl·liter-1 were observed, a result indicating that prolonged aminotriazole treatment inhibited ethylene action. Chemical names used: 3-1H-amino-1,2,4-triazole-1-yl (aminotriazole), 1-aminocyclopropane-1-carboxylic acid (ACC).

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Steven A. Altman and Theophanes Solomos

Sim-type carnation flowers (Dianthus caryophyllus L., cv. Elliot's White) continuously treated with 50 mM or 100 mM 3-amino-1,2,4-triazole (amitrole) and held in the dark at 18°C did not exhibit a respiratory climacteric relative to dH2O-treated controls. No morphological changes symptomatic of floral senescence appeared in treated flowers until 12-15 days post-harvest. Other triazoles were not effective in prolonging senescence. Amitrole appears to inhibit ethylene biosynthesis by blocking the enzyme-mediated conversion of S-adenosyl-L-methionine to 1-aminocyclopropane-1-carboxylate. Ethylene action appears to be progressively inhibited in that flowers held in treatment solution for 2 d or less responded to application of 10 uL/L exogenous ethylene whereas flowers held 10 d or longer exhibited no response. Electrophoretic resolution of total crude extracts evidenced protein synthesis as well as degradation. Western analysis and total activity assays showed an amitrole concentration-specific inhibition of catalase activity.

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Steven A. Altman and Theophanes Solomos

Continuous postharvest treatment of carnation flowers (Dianthus caryophyllus L. cv. Elliot's White) with 50 or 100 mM aminotriazole significantly extended useful vase life relative to flowers held in distilled H2O. No morphological changes symptomatic of floral senescence appeared in treated flowers until 12 to 15 days after harvest. The longevity of aminotriazole-treated flowers was extended to ≈18 days. The respiratory rate of aminotriazole-treated carnations was suppressed, and they exhibited no respiratory climacteric throughout the period of observation. The responsiveness of aminotriazole-treated flowers to exogenous ethylene appeared temporally regulated. Flowers treated with 50 mM aminotriazole for 2 days senesced in response to application of 10 μl exogenous ethylene/liter, whereas flowers treated for 24 days exhibited no morphological response to ethylene treatment. Chemical name used: 3-1H-amino-1,2,4-triazole-1-yl (aminotriazole).