Inhibition of Ethylene Biosynthesis and Action in Cut Carnations (Dianthus caryophyllus L.) by Aminotriazole

Abstract

<jats:p>Treating `Elliott's White' cut carnations with 50 or 100 m<jats:sc>m</jats:sc> 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 m<jats:sc>m</jats:sc> 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<jats:sup>-1</jats:sup>. Senescence-associated morphological changes, increased ACC synthase activity, ACC content, and ethylene evolution were completely inhibited in flowers treated for 4 days with 100 m<jats:sc>m</jats:sc> aminotriazole. Although treatment with 50 m<jats:sc>m</jats:sc> 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<jats:sup>-1</jats:sup> were observed, a result indicating that prolonged aminotriazole treatment inhibited ethylene action. Chemical names used: 3-1<jats:italic>H</jats:italic>-amino-1,2,4-triazole-1-yl (aminotriazole), 1-aminocyclopropane-1-carboxylic acid (ACC).</jats:p>

Ethylene Biosynthesis and Polyamine and ABA Levels in Cut Carnations Treated with Aminotriazole

“…The results obtained from this work showed that treatment with 50 mM ATA for 5 d increased the longevity of cut carnations by 4 d. Altman and Solomos (1993) also showed that 50 or 100 mM ATA applied continuously to cut carnations prolonged useful vase life, inhibiting physiological and morphological aspects of carnation senescence relative to flowers kept in distilled water. ATA completely inhibited the autocatalytic production of ethylene observed in the control carnations, probably due to an inhibition of the synthesis of the enzyme ACC synthase (Altman and Solomos, 1994). If the pathways of ethylene and polyamine biosynthesis compete for their common precursor SAM, it would be expected that in the carnations treated with ATA, in which the diversion of SAM towards ethylene is blocked, the levels of spermidine and spermine should be greater than those found in the control carnations.…”

“…However, ATA is not a general metabolic poison, since it does not inhibit enzymes such as ascorbate peroxidase and glutathione reductase (Amory at al., 1992). Altman and Solomos (1994) reported that ATA inhibits ethylene biosynthesis by inhibiting ACC synthase biosynthesis and the autostimulatory effect of ethylene, with the latter being temporally mediated. ATA has been classified as a putative carcinogen (Sine et al, 1991), so its commercialization as a cut-flower preservative is difficult.…”

“…compound, and is currently marketed for use as a postemergence, nonselective systemic herbicide (Sine et al, 1991). ATA is known to inhibit a variety of cellular metabolic processes including peroxisomal assembly of tetrameric catalase apoenzyme, CO 2 assimilation, mitochondrial protein biosynthesis, and the biosynthesis of imidazolglycerol-phosphate dehydratese, an enzyme of histidine biosynthesis in bacteria and fungi (Altman and Solomos, 1994;Amory et al, 1992). However, ATA is not a general metabolic poison, since it does not inhibit enzymes such as ascorbate peroxidase and glutathione reductase (Amory at al., 1992).…”

Quality and postharvest performance of cut roses grown in root media containing coal bottom ash

“…al., 1995). Altman and Solomos (1994) found that aminotriazole treatment of carnations increased their vase life and that the climacteric rise in respiration was greatly inhibited.…”