Postharvest physiology
S.A. Razi; D. Hashemabadi; B. Kaviani
Abstract
Introduction Carnation (Dianthus caryophyllus L.) is one of the most important cut flowers of the world. This flower is sensitive to postharvest ethylene and water stress and has short vase life. The use of retardants or inhibitors compounds of ethylene is an effective way to increase the postharvest ...
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Introduction Carnation (Dianthus caryophyllus L.) is one of the most important cut flowers of the world. This flower is sensitive to postharvest ethylene and water stress and has short vase life. The use of retardants or inhibitors compounds of ethylene is an effective way to increase the postharvest life of carnation. Polyamines including putrescine (diamine), spermidine (triamine) and spermine (tetraamine) as new groups of plant growth regulators that are involved in various processes including increasing cell division, increasing enzyme biosynthesis, regulation of different developmental stages, differentiation, flowering, embryogenesis, rooting and maturity. These compounds exert their anti-aging properties by competing with ethylene production. Polyamines are low molecular weight organic compounds with aliphatic nitrogen groups that have different hydrocarbon rings and two or more amino groups (positive charge agents). These organic compounds bind to cell membranes, nucleic acids, and other macromolecules and are involved in chromatin formation, ion channel control, free radical neutralization, and gene expression. Cell membrane strength and stability play an important role in increasing the post-harvest life of horticultural crops. Putrescine is the major polyamine in plants, which is a precursor to the synthesis of spermidine and spermine, and its positive effect on increasing the vase life of some cut flowers has been reported. Vase life of cut flowers of chrysanthemum, rose and gladiolus was increased by application of putrescine. The purpose of the present research was to increase the vase life of cut carnation flower using different putrescine concentrations and application methods. Materials and Methods A factorial experiment based on completely randomized design with 10 treatments in 3 replicates, 30 plots and 150 cut flowers was employed to investigate the effect of different concentrations of putrescine (0.01, 0.02 and 0.05 mM) and its application methods (continuous, pulse and spray) on vase life of cut carnation (Dianthus caryophyllus L.) flowers. Some other traits such as water uptake, dry mater percentage, decrease of fresh weight, the content of leaf chlorophyll and sepal carotenoid, POD and SOD enzymes activity, MDA, decrease of °Brix (sucrose percentage in flower stalk, soluble sugar in stem end and sepal), ionic leakage, ethylene were also measured. The statistical analysis of data was performed using SAS. The least significant difference (LSD) test at P < 0.05 was used for comparisons of different means of various treatments. Results and Discussion Results showed that the maximum vase life was recorded in cut flowers treated with 0.02 mM putrescine as spray application. The lowest ethylene production, the highest water uptake and superoxide dismutase enzyme activity was observed in 0.02 mM putrescine treatment. Some physiological parameters and enzymatic activity were also evaluated. The control treatment generally yielded the minimum values for most of the observed traits. Factors such as water stress, reduced carbohydrate levels, increased ethylene production, and the presence of microorganisms play pivotal roles in reducing the vase life of cut flowers. Polyamines are key in counteracting these stressors and delaying aging. They fulfill this role by fortifying the plasma membrane, suppressing the activity of hydrolytic enzymes, and inhibiting ethylene synthesis. Additionally, polyamines bind to cell wall pectin, safeguarding them from detrimental cell wall enzymes, including pectinase. They further impede flower maturation by inhibiting the production of essential enzymes required for ethylene synthesis and by dampening ethylene activity. Increasing polyamines by inhibiting lipid peroxidation is probably one of the mechanisms responsible for the anti-aging effect of polyamines. Polyamines have antioxidant properties so they reduce the number of oxygen free radicals and the permeability of plasma membranes by decreasing the activity of lipoxygenase, thereby increasing the vase life and quality of flowers. The use of polyamines to increase the vase life of some cut flowers has been reported, which the results of the present study are consistent with the results of these studies. Treatment of 20 mg l–1 spermine and 10 mg l–1 putrescine had the greatest effect on increasing vase life and reducing senescence of cut Alstroemeria flowers. Spermidine delayed the aging of carnation flowers. In cut rose cv. ‘Doles Vita’ flowers, the use of polyamines increased vase life. Treatment of 2 mM spermidine was the most suitable treatment to increase the vase life of cut carnation cv. ‘Red Corsa’ flowers. Cut rose flowers treated with humic acid and putrescine had the highest vase life compared to the control. Polyamines increased the vase life of cut gladiolus flowers by increasing the stability of plasma membranes. The addition of polyamines to the carnation flower preservative solution reduced their aging and prevented the production of ethylene. Polyamines appear to increase vase life in cut flowers by inhibiting ACC-synthase activity and reducing ethylene production. SOD, POD and catalase (CAT) enzymes, as antioxidant compounds, protect plants against reactive oxygen species and free radicals. Polyamines neutralize free radicals and are also involved in the synthesis of enzymes. Binding of polyamines to proteins protects them from the damaging effects of reactive oxygen species and free radicals. Treatment of 20 mg l–1 spermine increased the activity of SOD enzyme in cut Alstroemeria flowers. Concentrations of 10 and 20 mg l–1 putrescine and spermine significantly increased catalase activity. Spermidine treatment significantly increased the activity of free radical scavenging enzymes such as SOD and CAT. Putrescine in sunflower stimulated the catalase enzyme. At the first onset of senescence, antioxidant enzymes such as POD increase in petal cells to reduce the damaging effects of reactive oxygen species.
Sheno Amini; Mostafa Arab; Majid Rahemi; Abdolrahman Rahimi
Abstract
This research was carried out in order to evaluate the influence of different concentrations of ethanol and methanol (0, 4, 6 and 12%) and two pulse treatments (12 and 24 hour) on longevity of cut standard-carnation (Sensi cultivar) in a factorial based on randomized completely design with three replications, ...
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This research was carried out in order to evaluate the influence of different concentrations of ethanol and methanol (0, 4, 6 and 12%) and two pulse treatments (12 and 24 hour) on longevity of cut standard-carnation (Sensi cultivar) in a factorial based on randomized completely design with three replications, at Tehran University, Aboreyhan Pardis, horticulture department, during 2010. The results showed that the effect of alcohol treatments and interaction effect of alcohols and pulse on vase life were significant (at what level?????), whereas solution uptake and relative fresh weight were not affected by mentioned treatments. The highest (17.33 day) and lowest (11 day) amount of carnation vase life were obtained by ethanol 12% at pulse of 12 hours and control treatments, respectively. Ethanol 6% at pulse of 24 hours, ethanol 12% and methanol 6% at pulse of 12 hours were more effective in increasing the longevity of carnation than other pulse, while in other treatments, no significant differences were observed between the pulse times. Moreover, the highest of ethylene production obtained by control, while ethanol 4% and 6% at pulse of 24 hours, ethanol and methanol 12% at pulse of 12 hours and methanol 6% at both time of pulse markedly decreased the production of ethylene and lead to significantly increase in vase life. The relative extension of flowers and relative fresh weight had a positive correlation with vase life, while solution uptake had non correlation or negative correlation with other treats.
Azam Seddighi; M. Gholami; Hassan Sarikhani; Ahmad Ershadi
Abstract
The use of compounds inhibiting ethylene production is very important in post-harvest technology of fruits. Sweet cherry is a non-climacteric fruit with capability of ethylene production during storage period. Factors that decrease ethylene production would increase fruits storage life. In this research ...
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The use of compounds inhibiting ethylene production is very important in post-harvest technology of fruits. Sweet cherry is a non-climacteric fruit with capability of ethylene production during storage period. Factors that decrease ethylene production would increase fruits storage life. In this research sweet cherry fruits of Mashhad cv. were sprayed with different concentrations of Salicylic Acid (0.5, 1, 2, and 3 mmol/l) and Gibberelic Acid (0, 10, 20 and 30 mg/l). Fruits were sprayed about three weeks before harvest, when their color started to change from green to yellow. The experiment was performed in a completely randomized design with three replicates. The results showed that GA had less effect on decreasing ethylene production compared to SA, but did better on anthocyanin accumulation, fruit size, soluble solids content and fruit weight. GA treatment delayed fruit ripening and ethylene production but had little or no effect on the fruit color as an important ripening index. During storage period also the total amount of anthocyanin in fruits increased due to hormone treatments whereas the ethylene production decreased compared to control fruits.
