• Horticultural Science & Technology
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• v.29 no.4
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• pp.326-335
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• 2011

When bougainvilleas are subjected to indoor low-light conditions, flower bracts regularly abscise. This study elucidates the effects of plant growth regulators on bract longevity of potted bougainvillea. Potted 'Taipei Red' bougainvillea in four different bract development stages were treated with 1-MCP (1-methylcyclopropene), NAA (1-naphthaleneacetic acid), SNA (sodium salt of naphthaleneacetic acid), IBA (indolebutyric acid), BA (6-benzylaminopurine), $KH_2PO_4$ (potassium dihydrogen phosphate), Put (diamine putrescine), SA (salicylic acid), or STS (silver thiosulfate) and were moved to indoor low-light conditions after treatments. Experimental results indicate that 1-MCP, NAA, SNA, BA, Put, and SA prolonged bract longevity, and this effect increased as bract stage increased. The effect of STS was significant in early bract stages and decreased as bract stages increased. Additionally, 1-MCP, NAA, SNA, BA, Put, SA, and STS treatment significantly reduced endogenous ACC (1-aminocyclopropene-1-carboxylate) content and ACC oxidase activity, suggesting that the inhibition of ethylene production was achieved via physiological metabolism. However, treatment with IBA or $KH_2PO_4$ had no effect on the bract longevity at any stage. In the combined chemical treatments, NAA + STS or NAA + SA were effectively for prolonging bract longevity and contained less protein or chlorophyll degradation, decrease ACC oxidase or ethylene production than the control. In conclusion, we propose that combined chemical treatment significantly prolonged the bract longevity and more effectively than single chemical treatment at any stage.

• Horticultural Science & Technology
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• v.19 no.4
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• pp.545-549
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• 2001

The relationship between ethylene action and flesh softening in post-storage persimmon fruits was investigated by treating the fruits with 1-MCP. The patterns of firmness change caused by various treatments with 1-MCP and ethylene were similar to those of changes in cell wall-degrading enzyme activities, including cellulase, PG, PME, and ${\beta}$-galactosidase. Moreover, the activities of these enzymes were inhibited by 1-MCP treatment. These results show that the cell wall-degrading enzymes influenced by ethylene account for the flesh softening process of post-storage persimmon fruit. The ethylene production of fruits, as measured by ACC content and ACC oxidase activity, nevertheless, was not influenced by 1-MCP treatments. It is suggested that the flesh softening phenomena in post-storage persimmon fruits is correlated to the ethylene responsiveness of tissue rather than the ethylene production rate per se.

• Journal of Plant Biology
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• v.36 no.3
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• pp.233-239
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• 1993

Effect of Ca2+ on the conversion of 1-aminocycloprophane-1-carboxylic acid (ACC) to ethylene was studied with 2.5 day-old mung bean hypocotyl segments. The conversion of ACC in these tissues was inhibited by plasmolysis and sulfosuccinimidyl (hydroxyphenyl) propionate (sulfo-SHPP). The ACC induced ethylene production in HC (high calcium)-tissue grown on the Ca2+ added medium was greater than that in N (normal)-tissue. HC-tissue had a lower inhibition rate of ACC conversion by EGTA and Ca2+ -channel blockers than N-tissue. The rates of the ACC conversion by both kinds of tissues were stimulated by the Ca2+ ionophore A23187. From these results, we suggests a mechanism for the stimulative effect of Ca2+ on the conversion of ACC to ethylene as follows; in some tissues where ACC conversion is linked with plasma membrane, Ca2+ may be transported from apoplast through Ca2+ -channel into the cytoplasm ad stimulate ACC-oxidase activity.

• Proceedings of the Botanical Society of Korea Conference
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• 2002.04a
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• pp.92-92
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• 2002

• Horticultural Science & Technology
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• v.32 no.2
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• pp.261-268
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• 2014

Senescence of Hosta ventricosa flowers was firstly characterized as ethylene-sensitive since the deterioration of the tepal was accompanied by increased endogenous ethylene biosynthesis. The full-length cDNAs and DNAs of 1-aminocyclopropane-1-carboxylic acid (ACC) synthase (ACS) and ACC oxidase (ACO) involved in ethylene biosynthesis were cloned from H. ventricosa flowers. The HvACS ORF with 1347 bp and two introns, encoded a polypeptide of 448 amino acids showing 79% homology with that in Musa acuminata. The HvACO ORF contained 957 bp and three introns, encoding a 318-residue polypeptide showing 83% homology with that in Narcissus tazetta. The timing of the induction of HvACS expression was in correspond to the timing of the increase in ethylene production, and that the up-regulation of HvACO transcript was closely correlated with an elevated ethylene production, but underwent a down-regulation in wounded leaves with elevated ethylene emission. The results, together with expression analysis in vegetative tissues, suggested that both HvACS and HvACO were specifically regulated by flower senescence.

• Proceedings of the Zoological Society Korea Conference
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• 1994.10a
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• pp.189.1-189
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• 1994

• Journal of Plant Biology
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• v.35 no.4
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• pp.409-414
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• 1992

Effect of quercetin, a kind of natural plant flavonoids, on auxin-induced ethylene production in barley coleoptiles was studied. Auxin-induced ethylene production was apparently stimulated by quercetin. This stimulatory effect of quercetin appeared after 4 h of incubation period. Ethylene production was stimulated 200% over the control after 8 h of incubation by $3{\times}10^{-5}\;M$ quercetin. The quercetin effect was most prominent at $10^{-4}\;M$ of IAA. Ethylene production induced by the synthetic auxin, 2,4-D and NAA, was not significantly affected by quercetin. Also ACC-based ethylene production was unaffected by the flavonoid. In an effort to elucidate mechanisms of quercetin action on auxin-induced ethylene production, the effect of quercetin on 1M metabolism was studied. Data obtained from these experiments indicate that quercetin treatment resulted in about 90% inhibition of IAA oxidase activity. IAA ($3{\times}10^{-5}\;M$) conjugation was found to be not affected by quercetin. This results suggest that the stimulatory effect of quercetin on auxin-induced ethylene production may be due to the fact that quercetin inhibits 1M oxidase activity, thus increasing the free IAA level.

• Journal of Life Science
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• v.20 no.5
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• pp.745-749
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• 2010

This study was conducted to examine the effect of cytokinin ($N^6$-benzyladenine; BA) and/or an IAA on ethylene production of maize (Zea mays) primary roots. When the two hormones were applied exogenously, both hormones synergistically increased ethylene production, which was greater than the sum of the level of each hormone's effect. For example, the ethylene production was stimulated between about 87% and 170% of the control by $10^{-4}\;M$ BA with $10^{-4}\;M$ IAA for 8 hours respectively, whereas the ethylene production was increased by about 480% of the control when the two hormones were treated simultaneously. Such a synergistic effect was also found in changes in the activity and gene expression level of ACC synthase. However, in the case of ACC oxidase did not show any observable effects. Based on our results, it is possible to conclude that BA and IAA stimulated the ethylene production synergistically by affecting the ACC synthase in maize roots.

• Journal of Plant Biology
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• v.37 no.3
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• pp.271-276
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• 1994

The possibility that 1-aminocyclopropane-1-carboxylic acid (ACC)-uptake may be dependent on the H+-gradient established across the plsma membrane was tested in protoplasts isolated from 2.5 day old mungbean hypocotyls. The ACC-induced ethylene production was inhibited when the H+-gradient was collapsed by the treatment with carbonycyamide-p-trifluro-methoxy-phenylhydrazone (FCCP). Moreover, the treatment with o-vanadate, a specific inhibitor of plasma membrane H+-ATPase, caused the inhibition of ethylene production. The ACC-induced ethylene production was inhibited by the treatemnt with verapamil (Ca2+-channel blocker), or ethylene glycol-bis($\beta$-aminoethyl ether) N, N, N', N'-tetraacetic acid (EGTA) (Ca2+-chelator). In contrast, the ehtylene production was stimulated by the application of A23187 (Ca2+ ionophore). The inhibitory effect of EGTA in the ethylene producton was magnified in the presence of A23187. From these results, we suggest that the external Ca2+ influx to the cytosol resulted in the stimulatin of ACC oxidase activity after ACC-uptake resulting from a H+-gradient across the plasma membrane.

• Proceedings of the Zoological Society Korea Conference
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• 1998.10b
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• pp.259.1-259
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• 1998

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