Regulation of Senescence in Carnation (Dianthus caryophyllus)

Abstract

Abscisic acid hastened senescence of carnation flowers and this was preceded by stimulation of accelerated ethylene production. Carbon dioxide delayed the onset of autocataytic ethylene production in flowers regardless of treatment with abscisic acid. Flowers exhibited a low and transient climacteric of ethylene production without wilting while in 4% carbon dioxide and underwent accelerated ethylene production colninating in wilting when removed from carbon dioxide. Hypobaric ventilation, which lowers ethylene to hyponormal levels within tissues, extended flower longevity and largely negated enhacement of senescence by abscisic acid. Supplementing hypobarically ventilated flowers with ethylene hastened senescence irrespective of abscisic acid treatment.Collectively, the data indicate that abscisic acid hastens senescence of carnations largely as a result of advancing the onset of autocatalytic ethylene production.Abscisic acid and ethylene (together or separately) promote senescence of flowers (1,2,9,12,14). The interaction of abscisic acid and ethylene in the control of senescence has been reviewed by Sacher (17). Analysis of the interrelationships between these compounds is made difficult by complex interactions with numerous factors (13). Some (10) believe the effect of ABA to be mediated by ethylene, while others (6) consider it to be unrelated to ethylene. Conversely, ethylene has been demonstrated to promote a rise in the level of ABA (8,9,12).In this study, the effect of exogenous ABA and CO2 on ethylene production by cut carnation flowers was examined. enclosed in a 10-liter desiccator. Calcium sulfate was placed in each chamber to lower the humidity and prevent water condensation. The desiccators were maintained at 0.2 atm with constant ventilation (50 ml/min) with a gas mixture of 99.85% 02 and 0.15% CO2 with or without 2.56 ,ul/l ethylene until termination of the experiment. The gas mixtures were premixed in compressed gas cylinders and the composition was verified by gas chromatography. The chambers were opened daily for a brief period to evaluate flower development and renew the CaSO4. The experiment was performed twice in a growth chamber at 20 C under continuous fluorescent light and treatments were in quadruplicate. Other details of the hypobaric ventilation equipment are published (5). MATERIALS AND METHODSCarbon Dioxide Mixtures. Flowers were placed in 10-liter desiccators with CaSO4. Sodium hydroxide was placed in those chambers designated as the 0% CO2 mixture. The chambers were maintained at atmospheric pressure with air or a mixture of 4% CO2 in air at a flow rate of 50 ml/min. The gas concentrations were monitored frequently throughout the experiment.Ethylene Measurements. Flowers were enclosed in a specially constructed 500-ml glass chamber equipped with three ports. A port on the bottom served as a gas inlet and one on the top as an outlet for ventilation. The third port was fitted with a rubber serum bottle stopper and used for gas sampling with a syringe. One flower, with its s...

Difference in Flower Longevity and Endogenous Ethylene Production of <i>Portulaca umbraticola</i> Cultivars

“…Although the senescence of both P. umbraticola cultivars and I. nil 'Violet' is accelerated by exogenous ethylene, their senescence pathways tend to differ since they respond differently to ethylene action and ethylene biosynthesis inhibitors. The plant growth hormone ethylene is known to hasten the senescence of many cut flowers such as carnations (Mayak et al, 1976;Satoh, 2011) and Portulaca hybrid (Ichimura and Suto, 1998a). This was almost the same scenario as how exogenously applied ethylene accelerated senescence of both SR and SCR.…”

Longevity of torch ginger inflorescences with 1-methylcyclopropene and preservative solutions

“…Çelikel et al (2002b) assessed the use of 1-MCP associated with Promalin (1.8% GA 4+7 + 1.8% BAP) in the postharvest preservation of lilies and observed the superiority in the preservation of such plants. According to Nowak and Rudnicki (1990), the use of commercial preservative products promotes practicality, since it eliminates the frequent need of solution change during storage. Furthermore, the quality increase implies both economic empowerment and product expansion to consumers (PRADO et al, 2005).…”

“…The water excessive loss through transpiration and/or obstructions of the xylem vessels cause the wilt, reducing the longevity. Thus, the flowers that loose between 10 and 15% of fresh matter mass may be considered wilt (NOWAK; RUDNICKI, 1990).…”

“…The abscission and senescence processes may be accelerated by the increase of the ethylene yield (SANTOS et al, 2005), which exerts influence upon the tissue turgidity, accelerating the flower wilt (MAYAK et al, 1977). According to Ciardi and Klee (2001), the sensitivity and response level to the ethylene are dependent on the developmental and perceptive stage of the plant's organ.…”

“…Generally, the cut flowers present a limited postharvest life due to its physiological and morphological traits -being subjected to deterioration processes similar to fruits (PETRY et al, 2000). According to Sousa et al (2002), the quality maintenance is due to postharvest storage Acta Scientiarum.…”