Effect of sucrose on sensitivity to ethylene and enzyme activities and gene expression involved in ethylene biosynthesis in cut carnations

• Published in: Postharvest biology and technology 2016-11, Vol.121, p.151-158
• Main Authors: Pun, Umed Kumar, Yamada, Tetsuya, Azuma, Mirai, Tanase, Koji, Yoshioka, Satoshi, Shimizu-Yumoto, Hiroko, Satoh, Shigeru, Ichimura, Kazuo
• Format: Article
• Language: English
• Subjects: 1-Aminocyclopropane-1-carboxylate oxidase (ACO); 1-Aminocyclopropane-1-carboxylate synthase (ACS); Carnation (Dianthus caryophyllus); Cut flower; Dianthus caryophyllus; Soluble carbohydrate; Vase life
• ISSN: 0925-5214; 1873-2356
• DOI: 10.1016/j.postharvbio.2016.08.001

•Sucrose treatment delayed petal senescence and climacteric ethylene production.•Sugar levels decreased in control and decreased further by sucrose treatment.•Sucrose treatment delayed the increases in ACS and ACO activity.•Sucrose treatment delayed the increases in DcACS1 and DcACO1 expression.•Sensitivity to ethylene was not reduced by sucrose treatment. Application of sugars extends the vase life of many cut flowers. The role of applied sucrose in petal senescence of cut carnations (Dianthus caryophyllus cv. Barbara) was investigated. Petal senescence was significantly delayed by 5% sucrose treatment. Although glucose, fructose, and sucrose concentrations decreased in the petals of control flowers with time, these concentrations increased on sucrose treatment. To investigate the effect of sucrose on sensitivity to ethylene, flowers were pre-treated with aminoethoxyvinyl glycine (AVG) to avoid the effect of ethylene biosynthesis and placed in a sucrose solution for 0 and 5 days. Flowers were then exposed to ethylene at 0.2, 0.6, and 2μLL−1. Sucrose treatment did not delay petal senescence by ethylene exposure on day 0, suggesting that the effect of sucrose on the sensitivity to ethylene is negligible. Petal wilting was not accelerated by ethylene exposure at 0.2, 0.6, and 2μLL−1 without sucrose treatment on day 5, but sucrose treatment did not delay petal wilting, implying that sucrose treatment maintains sensitivity to ethylene in the aged flowers. Sucrose treatment delayed climacteric-like increase in the ethylene production of petals and gynoecium. 1-Aminocyclopropane-1-carboxylate (ACC) synthase (ACS) and ACC oxidase (ACO) activity in petals increased during senescence, and sucrose treatment delayed the increase in ACS activity and suppressed the increase in ACO activity. The transcript levels of the ACS gene DcACS1 and the ACO gene DcACO1 in petals increased during flower senescence, and sucrose treatment delayed the increase in the transcript levels of DcACS1 and suppressed the increase in the transcript levels of DcACO1. These results suggest that delay in petal senescence by sucrose treatment is due to maintenance of sugar level in the petals, which delays a climacteric-like increase in ethylene production. The delay in ethylene production is associated with ACS and ACO activities regulated mainly at the transcriptional level.