Postharvest physiology
Seyyed Abbas Razi; Davood Hashemabadi; Behzad 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.
Ornamental plants
Mohadeseh Piri; Zohreh Jabbarzadeh
Abstract
Introduction Lisianthus (Eustoma grandiflorum) from Gentianaceae family is from wild flowers of north and west America. Lisianthus, a relatively new floral crop to the international market, quickly ranked in the top ten cut flowers worldwide due to its rose-like and blue flowers. It is also widely ...
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Introduction Lisianthus (Eustoma grandiflorum) from Gentianaceae family is from wild flowers of north and west America. Lisianthus, a relatively new floral crop to the international market, quickly ranked in the top ten cut flowers worldwide due to its rose-like and blue flowers. It is also widely used as a flowering potted and bedding plant. Lisianthus ‘Mariachi Blue’ is cultivated as a cut flower. Salicylates have very beneficial effects on plant growth and development. The effect of phenolic compounds in many biochemical and physiological processes including photosynthesis, ion adsorption, membrane permeability, enzyme activity, flowering, stimulation of plant resistance systems, heat production and plant development has been proven. The most famous member of this group is salicylic acid, which as a simple phenolic compound, is naturally produced by plants. Salicylic acid (SA) is considered to be plant signal molecule that plays a key role in plant growth, development, and defense responses. Polyamines (PAs) are ubiquitous and biogenic amines that have been implicated in cellular functions in living organisms. In plants they have been implicated in a wide range of biological processes including cell division, cell elongation, senescence, embryogenesis, root formation, floral initiation and development, fruit development and ripening, pollen tube growth and plant responses to biotic and abiotic stress. Sodium nitroprusside is a nitric oxide releasing agent. Nitric oxide is a gaseous free radical that can disperse very rapidly through cell membranes due to its gaseous nature and medium shelf life, without a carrier. Nitric oxide (NO) is an unstable environmentally-friendly gas radical that is used to protect the postharvest longevity of different horticultural crops. In addition to controlling harvested crop senescence, NO is involved in many plant processes, e.g., germination, growth and development, photosynthesis, pigment synthesis, defensive system, and many others. In the present study, we investigated the effects of foliar application of salicylic acid, spermidine and sodium nitroprusside on some morpho-physiological characteristics and vase life of lisianthus flowers ‘Mariachi Blue’.Materials and Methods This study was conducted based on a completely randomized design with 10 treatments, 4 replications which each replication containing 2 pots. The treatments were included spermidine at concentrations of 0.5, 1 and 2 mM, salicylic acid at concentrations of 0.5, 1 and 1.5 mM, sodium nitroprusside at concentrations of 50, 100 and 200 μM and control (without any application of growth regulators) as foliar application at intervals of 15 days for 2 months. Plant characteristics including leaf area, stem length, fresh and dry weight of leaves and flower, number of buds, flowers’ length and diameter, photosynthetic pigments and vase life were assayed. To perform analysis of variance and compare the mean of the studied traits, SAS software version 9.1 was used. The means were compared using the Tukey multi-domain method at a probability level of 1%. Also, Excel (2016) software was used to draw the chart. Results and Discussion The results obtained from analysis of variance in this study showed that the effect of growth regulators used in the study was significant at the level of 1% probability on all morphological traits measured, photosynthetic pigments and vase life of lisianthus flowers. Mean comparison graphs showed that salicylic acid, spermidine and sodium nitroprusside had a positive effect on some morphological traits, photosynthetic pigments and vase life compared to control. It can be concluded that, salicylic acid caused to increase all parameters except the flowers’ fresh weight compared to control. Spermidine increase stem length, leaf fresh weight, flowers’ fresh and dry weight, length, and diameter, chlorophyll index, chlorophyll b, and carotenoid and vase life of flowers. Also, sodium nitroprusside had beneficial effects on all parameters in this research except leaf area, leaf dry weight, chlorophyll a and vase life of flowers. Salicylic acid plays an important role in regulating some physiological processes of plants such as growth and development, ion uptake and transport, stomatal conductivity, and membrane permeability, which is effective in plant photosynthesis and with increasing photosynthesis, plant growth rate increases. Polyamines such as spermidine are involved in a wide range of developmental stages including cell division, embryogenesis, root growth, and flowering. Sodium nitroprusside is involved in the most important plant processes such as photosynthesis, respiration, growth and cell division. Probably, these growth regulators, due to their effect on plant growth, flowering, as well as photosynthetic pigments, have caused the increment of plant biomass and vase life.Conclusion In the present study, the effect of salicylic acid, spermidine and sodium nitroprusside on some growth and flowering characteristics, photosynthetic pigment and vase life of Eustoma grandiflorum ‘Mariachi Blue’ was assayed. According to the results of the present study, it can be concluded that these growth regulators improved growth indices, flowering parameters, photosynthetic pigment and vase life of flowers. According to the results, the appropriate concentrations for salicylic acid were 1 mM, for spermidine, 1 mM and for sodium nitroprusside were also 50 and 100 μM.
Ornamental plants
Maryam Hojatipour; Moazam Hassanpour Asil
Abstract
Introduction
Lilium flower is a perennial herbaceous flowering plant, belonging to the Liliaceae family. Position of lilies as the fourth best-seller cut flower in the world, as well as the increasing trend of demand for this flower in the global market, indicates the importance of improving the ...
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Introduction
Lilium flower is a perennial herbaceous flowering plant, belonging to the Liliaceae family. Position of lilies as the fourth best-seller cut flower in the world, as well as the increasing trend of demand for this flower in the global market, indicates the importance of improving the quality and solving the sustainability issues of this flower. Gibberellins are one of the most important endogenous plant hormones involved in controlling plant dormancy. Gibberellin is a plant growth regulator that stimulates physiological responses in plants by affecting photosynthesis. Polyamines, including putrescine, spermidine, and spermine, are a group of plant growth regulators that have effects such as increasing cell division, biosynthesis of enzymes, regulating various developmental stages such as differentiation.
Materials and Methods
This study was performed to investigate the effect of gibberellic acid and putrescine on growth, flowering and vase life of Lilium cut flowers. Experiment was performed as factorial based on completely randomized design, included 16 treatments with 3 replications and 2 pots in each replication. The culture medium containing mold leaf soil, sand and perlite (1:1:1) and was prepared by disinfection with fungicide. The first treatment consisted of concentrations of 150, 300 and 450 mg/L gibberellic acid and onions were pre-treated by immersing for 24 hours. The second treatment consisted of concentrations of 0.5, 1 and 2 mM putrescine which was sprayed at the beginning of budding and continued every two weeks until the first bud flower coloring. Growth period conditions in green house were controlled. In this study, different parameters such as bud number, flowering stem length, fresh weight of cut flowers, relative fresh weight of cut flowers, water uptake of cut flowers, vase life, leaf chlorophylls a, b and total, petal carotenoid, percentage of petal cell membrane stability and total soluble solids of petals were examined.
Results and Discussion
The results showed that the application of gibberellic acid and putrescine improved the number of buds and increased cell membrane stability. Actually, gibberellic acid preserves the cell membrane by preventing the breakdown of proteins and increasing the pH, thus increasing the vase life. Also Putrescine protects cell membranes by removing free radicals. It is also known that gibberellic acid used at all levels in the experiment increased the height of the flower stem due to its role in cell division and elongation. Study of the flower stem water content and cut flower fresh weight, which are factors for longer vase life, showed that gibberellic acid increases the plant's ability to absorb water and increases these two traits. So that the highest cut flower fresh weight with 13 g difference compared to the control level belonged to the treatment level of 450 mg/L gibberellic acid. Also putrescine reduces plant water loss by increasing membrane permeability to calcium and increases the flower stem water content and cut flower fresh weight, which increases vase life. Also, gibberellic acid by creating water potential in the cell and putrescine by strengthening water relations and preventing blockage of water vessels increased the relative water uptake of cut flower. Thus, the greatest effect was observed on the third day post-harvest and the highest amount (2.47 ml. g-1 FW) on the third day belonged to the highest level of both treatments. Results also showed that all the levels of putrescine increased TSS due to its effect on the synthesis of sugars and carbohydrates in compared to control. The results showed that application of gibberellic acid and putrescine respectively at 300 mg/L and 2 mM, significantly increased the vase life compared to the control. The best vase life (15 days) occurred at 300 mg/L gibberellic acid and 2 mM putrescine. Although gibberellic acid increased growth and flowering of Lilium, but putrescine effectiveness on vase life of cut flower was more evident. The highest amount of leaf total chlorophyll (0.514 mg. g-1 FW) belonged to the treatment of 450 mg/L gibberellic acid and 2 mM putrescine and the lowest amount of leaf total chlorophyll (0.085 mg. g-1 FW) belonged to both treatments were at the control level. Also, in the study of petal carotenoid content, the highest amount belonged to the treatment of 450 mg/L gibberellic acid and 2 mM putrescine.
Conclusion
According to the results obtained from the present research, it can be concluded that use of gibberellic acid and putrescine had great effects on most of traits in compared to control treatment. The use of putrescine and gibberellic acid improves the flowering and vase life conditions by increasing water uptake and consequently increasing the relative fresh weight.
Ornamental plants
Roghayeh Abdi; Zohreh Jabbarzadeh
Abstract
Introduction The genus Rosa from the family Rosaceae with over 150 species is one of the most important ornamental plants in the world. From a commercial point of view, cut roses play a key role in trade of cut flowers. Nitric oxide regulates key physiological processes that depend on the concentration ...
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Introduction The genus Rosa from the family Rosaceae with over 150 species is one of the most important ornamental plants in the world. From a commercial point of view, cut roses play a key role in trade of cut flowers. Nitric oxide regulates key physiological processes that depend on the concentration of this compound such as hypocotyls growth, defensive responses, growth and development, photosynthesis, and phytoalexin generation in stressful conditions. Polyamines are key biomolecules that have a role to play in the regulation of many plants’ growth and development processes and their responses to different environmental stimuli. This study was performed to investigate the effect of foliar application of sodium nitroprusside (as a NO donor) and putrescine (as a polyamine) on ‘Avalanche’ rose in hydroponic conditions.Materials and Methods This study was conducted in the research and production greenhouses of Urmia University and the research laboratory of the Department of Horticultural Sciences of the Faculty of Agriculture in 2019-2020 on rose (Rosa hybrida ‘Avalanche). This experiment was conducted as a factorial trial based on completely randomized design with two factors including sodium nitroprusside in four concentrations of 0, 50, 100 and 200 μM and putrescine in four concentrations of 0, 1, 2 and 4 mM with 3 replications as a foliar application under hydroponic conditions in greenhouses and in pots. The treatments were applied two weeks after transplantation, every 15 day-interval for 4 months. In order to investigate the effects of putrescine and sodium nitroprusside on some morphological and physiological characteristics of plants, two weeks after the end of treatments, sampling was performed to measure morphological and physiological characteristics. The measured indicators included: fresh and dry weight of flowering stem, chlorophyll a, b and total chlorophyll, carotenoids and also in the postharvest stage were guaiacol peroxidase and ascorbate peroxidase enzymes activity and bending of flowering stem. The SAS software version 9.2 was used to analyze the variance and compare the mean of the studied traits. Comparison of means was performed using the Tukey’s range test method at a probability level of 1 and 5%. Also, Excel (2016) software was used to draw the graph.Results According to the means comparison of measured parameters, sodium nitroprusside along with putrescine increase the flowering stem fresh and dry weight, photosynthetic pigments of leaves and antioxidant enzymes activities at the postharvest stages. Sodium nitroprusside at a concentration of 50 μM with 4 mM putrescine increased the fresh and dry weight of the flowering stem. Also, the concentration of 100 μM sodium nitroprusside with 4 mM putrescine significantly increased chlorophyll a, b, total chlorophyll and carotenoid content compared to control. It should be noted that preharvest application of sodium nitroprusside along with putrescine cause to improve postharvest characteristics of rose. In this research, application of 100 and 200 μM SNP alone or with different concentrations of putrescine increased guaiacol peroxidase and ascorbate peroxidase activity and reduced bending of flowering stem of rose ‘Avalanche’ at the postharvest stage. Probably polyamines (such as putrescine) and nitric oxide increase photosynthesis potential with increasing photosynthetic pigments and protecting cell membranes thus increase growth and flowering traits of plants such as increasing the flowering stem weight of rose in this research. At postharvest stage, senescence of flowers is an inevitable phenomenon that cause to produce free radicles in plants. Free radicles injure the plant membranes lipids and change the antioxidant enzymes activities. This despite the fact that nitric oxide and putrescine protect antioxidant enzymes against free radicles as a result can improve vase life of rose. Conclusion Based on the results of the present study, it can be concluded that putrescine, with SNP, improves growth characteristics as well as increases the postharvest traits and quality of cut flowers of rose. According to the results, it is observed that among the different concentrations of putrescine, the concentration of 4 mM had the greatest effect on the growth and physiological parameters of rose while the concentration of 100 and 200 μM sodium nitroprusside had a greatest effect on physiological characteristics and postharvest traits of rose. In general, both SNP and putrescine had a positive and favorable effects on improving growth and postharvest indices, but the effective concentration varied depending on the type of parameter.
Mohammad Soleimani; Mostafa Mobli; Ali Akbar Ramin; Bahram Baninasab; Leila Aslani
Abstract
Introduction: Cold stress is one of the limiting factors for plant growth and yield production in most parts of the world. Cold stress damages cells through changes in the activity of macromolecules, decreasing osmotic potential, and significant changes in other parts of the cell. Cold stress in young ...
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Introduction: Cold stress is one of the limiting factors for plant growth and yield production in most parts of the world. Cold stress damages cells through changes in the activity of macromolecules, decreasing osmotic potential, and significant changes in other parts of the cell. Cold stress in young seedlings generally reduces leaf development, induces wilting and chlorosis and in more severe cases, browning and necrosis become visible. Cucumber is a sensitive plant to low temperature and its cultivation, except the southern and central parts of Iran, occurs in areas where there is a possibility of cold stress in the early part of the growing season due to the low temperature. The different ways for controlling cold stress had been used; one of them is using plant growth regulators such as spermidine. Spermidine is one of the polyamines that has been used in recent years to control cold stress. The effect of cold treatment on the amount of indigenous leaf polyamines has been reported differently between cold-resistant and sensitive cucumber cultivars. During the cold stress, the amount of indigenous spermidine in leaves of cold-resistant cucumber cultivars and sensitive cultivars increased significantly and remained unchanged, respectively. The increase in the content of putrescent, spermidine and spermine in cold resistant cultivars during cold stress was probably due to the increased activity of ornithine decarboxylase (ODC). The amount of polyamines in chickpea plants that were exposured to low temperatures (12-15°C and 4-6°C are related to mean maximum and minimum temperature of the farm, respectively) increased six to nine times. Adding spermidine to the cucumber growing medium before applying cold treatment increased spermidine amount in all organs and increased cold tolerance.
Materials and Methods: To study the effect of spermidine on cold tolerance of cucumber, seedling of ‘Rashid’ cultivar, an experiment was conducted based on completely randomized design with four replications and four treatments consist of different concentrations of spermidine (0, 0.1, 0.5 and 1 mM) in incubator of College of Agriculture, Isfahan University of Technology. So seeds were exposed to 20°C for 7 days in a humid condition and then were treated with 0, 0.1, 0.5 or 1 mM spermidine, the remaining 8 days they were kept at 6 or 9°C. The treatments performed in dark conditions until the second day of germination and received 8 hours of light daily from the third day until the end of the experiment. At the end of each experiment, shoot and root length were measured by use of the ruler, shoot and root fresh and dry weight were measured by use of digital scale, shoot and root ion leakage were measured based on Lates method (3) and shoot and root proline concentration were measured based on Bites et al., (2) method. To compare the effects of temperature and its interactions with spermidine, data of two experiments analyzed as split plot experiment (Different temperatures and spermidine concentrations were as main and subplots, respectively).
Results and Discussion: The findings of this study showed that application of the highest concentration of spermidine (1 mM) in 9°C had the inverse effect on cold tolerance, so it decreased the fresh and dry weight of root. In 6°C, 0.5 mM spermidine was more effective than other concentrations, and it increased root fresh weight, shoot proline concentration and decreased root ion leakage. It has been shown that the non-saturated lipid profile of membranes of cold-resistant plants in comparison of non-resistant plants is significantly increased, and this increase is associated with a decrease in cell ion leakage. Proline works as a nitrogen source and soluble substance that helps the plant to combat again stress conditions. The split-plot analysis of data showed that 0.5 and 0.1 mM spermidine treatments increased root length, root fresh and dry weight significantly. The study of spermidine concentrations ×temperatures showed that the increasing effect of 0.5 mM spermidine on root length, root fresh and dry weight was only visible in 6°C.
