Postharvest physiology
Mahroo Sadat Motaghayer; Majid Azizi; Ali Tehranifar
Abstract
Introduction: Gerbera (Gerbera jamesonii Bolus, Asteraceae) commonly known as Transvaal Daisy, is one of the ten most popular and important commercial cut flowers. Gerbera is a perennial, tropical, herbaceous plant with colorful and attractive flowers that are widely used as a decorative garden plant ...
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Introduction: Gerbera (Gerbera jamesonii Bolus, Asteraceae) commonly known as Transvaal Daisy, is one of the ten most popular and important commercial cut flowers. Gerbera is a perennial, tropical, herbaceous plant with colorful and attractive flowers that are widely used as a decorative garden plant or cut flowers. The most important problem of the gerbera cut flowers is short vase life. The end of vase life of cut gerbera flowers is often due to bending of the scape. The aim of this study was to screen the effects of nanosilver and salicylic acid as pulse treatment and sucrose and thyme, clove and peppermint essential oils as permanent treatment on vase life and some physiological and biochemical traits of gerbera ‘Rosalin’ cut flowers.Materials and Methods: This study was conducted as a factorial experiment based on completely randomized design with three replications. The first factor was pulse treatments using nanosilver (NS) 5 and 10 mg/L (Nanocid Company, Iran), salicylic acid (SA) 50 and 100 mg/L (Merck Company) and distilled water as control, and the second factor was permanent treatments applying distilled water, sucrose 4% (Merck Company), peppermint (100 mg/L), thyme (100 mg/L) and clove (300 mg/L) essential oils (EO) (Zardband Company, Iran). Pulse treatments were applied for 24 h. Treated stems were then stood into vases containing permanent treatments. Vase solutions were freshly prepared at the beginning of the experiment and not renewed during of the study. The measured traits were: flower vase life, flower water content (WC), relative fresh weight (RFW), water loss (WL), water uptake (WU), total soluble solid (TSS), superoxide dismutase (SOD) enzyme activity and malondialdehyde (MDA) amount (Biovision Colorimetric Assay Kit, USA). The experiment was conducted in the laboratory at 20-22°C, 40-50% RH, and 15 µmol/m2s light intensity (cool white florescent tubes) under a daily light period of 12 hours. The obtained data were analyzed using MSTAT-C program and mean comparison was done using LSD range test.Results and Discussion: The results showed that NS 10 mg/L with thyme EO 100 mg/L (14.25 days) and NS 10 mg/L followed by peppermint EO 100 mg/L (14 days) had the best effect on longevity and maintaining the water content of gerbera cv. ‘Rosalin’ cut flower, compare to other treatments. Flower WC was high (about 90%) except in 4% sucrose permanent treatment flowers which had negative effect and decreased more rapidly during the vase life period. Despite of antimicrobial preservative application, RFW, WU, WL and TSS generally had a decreasing trend during the experiment. However, it was observed that flowers treated by NS 10 mg/L (0.86 g/g) and thyme (0.77 g/g) and peppermint (0.72 g/g) EOs had the most RFW on the eighth day of experiment, but 4% sucrose (0.59 g/g) permanent treatment reduced RFW during cut flower vase life. The highest WU was respectively observed in SA 100 mg/L (67.28 g), NS 5 (61.31 g) and 10 mg/L (60.35 g) on the second day. According to the results of this research, pulsing by NS 5 and 10 mg/L and SA 100 mg/L resulted in the the most WL on day two (64.24, 57.85 and 64.95 g respectively). TSS of the cut flowers decreased with time, however reduction rates were delayed in SA and NS treated flowers. On the eighth day of experiment, long-term treatment showed the most effect on TSS amount. Flowers treated by NS 10 mg/L followed by 4% sucrose and peppermint EO treatment had the highest TSS amount, respectively 3.50 and 3.17 Bx. As the time passed, the activities of SOD enzyme increased, however, treated flowers showed significantly higher SOD activity compared to the control. Especially NS 10 mg/L pulse treatment, followed by thyme and peppermint EOs, indicated by the highest amounts (241.43% and 233.94%) of SOD activity on seveth day of the experiment. During the experiment, MDA increased in the flowers, so that the highest amount of MDA was detected in control (67.30%) on the seventh day and the lowest was produced in NS 10 mg/L treated flowers followed by thyme (14.88%) and peppermint (19.44%) EOs. Due to the fact that these treatments had the best effects on flower vase life, these results are logical.Conclusions: Based on the results of this study, new antimicrobial agents such as NS, thyme and peppermint EOs had a positive effect on flower vase life, WC, RFW and WU and reduced the rate of WL and TSS reduction in flowers. It might be due to this fact that these are very effective antimicrobial agents, inhibited the microbial growth and prevented bacterial plugging in conducting tissues. NS particles enter to cell, tissue and organs, so they can inhibit the respiration and electron transfer system and material transfer in microbial cell membrane. The application of natural phenolic compound like EOs reduced the accumulation of MDA and enhanced SOD enzyme activity. Therefore, due to the undesirable results of chemical preservative on human and environmental health, EOs can be very good substitutes for preserving cut flowers postharvest life.
Postharvest physiology
Davood Hashemabadi; Amirhossein Soleimani; Behzad Kaviani; Nayyereh Naziri Moghaddam
Abstract
IntroductionCut carnation flowers have high economic importance in the floriculture industry. The postharvest life of cut ornamentals, including carnation, is important in determining their quality and consumer preference. High production of ethylene is one of the most important factors that reduce the ...
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IntroductionCut carnation flowers have high economic importance in the floriculture industry. The postharvest life of cut ornamentals, including carnation, is important in determining their quality and consumer preference. High production of ethylene is one of the most important factors that reduce the postharvest life of this flower. High ethylene production causes the aging of some cut flowers. In order to increase the vase life of cut flowers, many researches have been done and various preservative solutions have been introduced, and in some of these solutions, disinfectants have also been used. One of the effective compounds in stopping or reducing ethylene production are alcohols. Ethanol stops ethylene synthesis in cut carnation. Cut carnation is climacteric flower and sensitive to high levels of ethylene. Therefore, the aim of this research was to investigate and compare the effect of different amounts of propanol, butanol and pentanol on the vase life and quality improvement of cut carnation flowers cultivar 'Nelson'.Materials and MethodsIn the present study, propanol, butanol and pentanol were used at the concentrations of 2, 4 and 6% for 24-hour pulse, in order to reduce ethylene production and increase the vase life of cut carnation cultivar 'Nelson' flowers. In February 2020, cut carnation flowers that were harvested at the commercial stage were prepared from a greenhouse in Mahalat city and were immediately transferred to the Postharvest Laboratory, Faculty of Agriculture, Islamic Azad University, Rasht Branch for treatment and evaluation of traits. This experiment was conducted as a completely randomized design in 30 plots. For each treatment, 3 replications and 5 samples for each replication and a total of 150 flower branches were considered. Some traits such as vase life, water absorption, dry matter, petal protein, leaf chlorophyll, ethylene production, fresh weight loss, flower opening index, Brix degree, lipid peroxidation and activity of antioxidant enzymes, peroxidase and superoxide dismutase were measured. To evaluate the vase life of cut flowers, the main criterion is the turning of the petals inward and the apparent wilting of the flowers. Data analysis was done using SAS statistical software and mean comparison based on Duncan's multiple range test.Results and DiscussionThe results of variance analysis of the data showed that the effect of different amounts of propanol, butanol and pentanol application was significant at 5% and 1% probability level on vase life and most of the traits measured in cut carnation flowers. This research revealed that propanol had a more effective role in reducing ethylene production and increasing the vase life than butanol and pentanol. The results showed that the longest vase life (14.11 days) was observed in cut flowers treated with 2% propanol. This treatment also caused the highest amount of water absorption, percentage of dry matter, petal protein and leaf chlorophyll, as well as the lowest amount of ethylene production. The lowest vase life (8.91 days) was observed in control cut flowers. The mean comparison of the different alcohol treatments showed that all treatments of propanol and butanol alcohols in different concentrations increased the absorption of solution by cut flowers compared to the control. Maintaining the water balance in cut flowers is one of the important factors in the vase life of cut flowers. The content of water uptake by cut flowers depends on the hydraulic conductivity of the water channel in the stem and the water potential difference between cut flower tissues and the preservative solution. The least plasma membrane damage was caused in cut flowers treated with 2% propanol. This treatment also caused the highest SOD activity. The short vase life of cut flowers is a global challenge, and efforts are being made to increase their vase life by using appropriate compounds in the vase solution. One of these compounds are alcohols, which have been used by some researchers in order to increase the vase life of various cut flowers. Alcohols are usually toxic for cells in high concentrations. Propanol and butanol in low concentrations inhibited the synthesis of ethylene and therefore increased the vase life of cut carnation flowers. These anti-ethylene compounds prevent the senescence of the petals, which is usually associated with the browning of the petals. Alcohols in optimal concentrations act as a signal and increase the vase life of cut flowers and improve their postharvest quality by reducing lipid peroxidation and inducing the activity of antioxidant enzymes. Similar findings were reported in cut alstroemeria, some carnation cultivars and chrysanthemum flowers.ConclusionThe present study showed the positive effect of disinfectant and antimicrobial compounds on increasing the vase life, some physiologic characters and antioxidants activity. This research revealed that propanol had more effective role in reducing ethylene production and increasing the vase life than butanol and pentanol. The results showed that the longest vase life was observed in cut carnation cv. Nelson flowers treated with 2% propanol.
Postharvest physiology
Fatemeh Ahmadi; M.M. Sharifani; Amir Mousavi; Negin Akhlaghi Amiri; Mostafa Khoshhal Sarmast; Khalil Zaynali Nezhad
Abstract
IntroductionExternal and internal quality of citrus such as color, shape and taste increase economic benefit. The vigour of each rootstock causes qualitative and quantitative change and the effective factor on commercial maturity, which is important for gardeners and producers. Considering the characteristics ...
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IntroductionExternal and internal quality of citrus such as color, shape and taste increase economic benefit. The vigour of each rootstock causes qualitative and quantitative change and the effective factor on commercial maturity, which is important for gardeners and producers. Considering the characteristics of the fruit in grafted trees, the present research was conducted with the aim of evaluating the effects of Poncirus, Citrange and Citrumelo rootstocks on some morphological, phytochemical and molecular traits of Thomson Navel orange fruit. Materials and MethodsThis research was carried out in 2018 at Ghaemshahr Horticultural Research Station, Mazandaran. It was conducted in the form of randomized complete block design (RCBD) of uniform and 10-year-old Thomson Navel orange grafted on Poncirus, Citrange and Citrumelo rootstocks with four replications. The samples were collected at the end of October and were transferred to the research laboratory of Horticulture Department, Gorgan University of Agricultural Sciences and Natural Resources for further research. Measurements were made on the morphological traits, quality characteristics of the fruit, the phenolic compounds of the peel and the pulp of the fruit and relative expression of fruit pulp sucrose phosphate synthase1 gene. Data variance analysis was done using SAS software (version 9.0). Mean comparisons were done with Duncan's multiple range test. Results and DiscussionThe results of analysis of variance showed that the rootstock effect on traits of length-to-diameter ratio, weight and density of Thomson Navel orange was significant at the five percent probability level (p<0.05) and the fruit length and diameter traits were significant at the one percent probability level (p<0.01). The results of mean comparison showed that the characteristics of length, diameter, length-to-diameter ratio, weight and density of Thomson Navel orange at Commercial Maturity on the Poncirus rootstock were more than the two other rootstocks. Due to the early harvest, the density of the fruit was recorded lower than one, so that the highest amount (0.5 g per cm3) was observed in the rootstock of Poncirus. Although it was not significantly different from Citrange rootstock. Based on the results of analysis of variance, it showed that the effect of rootstock on total soluble solids was significant at the level of five percent. Also, the rootstock had a significant effect on titratable acidity, taste index, vitamin C, acidity, EC and total sugar at the level of one percent. However, the amount of vitamin C was higher in the Citrumelo rootstock. The highest amount of acidity and EC belonged to Poncirus rootstock and the lowest amount belonged to Citrange rootstock. The highest amount of total sugar was observed in the dwrafing Poncirus rootstock, while its lowest amount was recorded in the vigorous Citrumelo rootstock. The highest amount of total soluble solids was observed at the rootstock of the Poncirus. The amount of titratable acid in the Citrange rootstock was higher than the other two rootstocks. The taste index was higher in the Poncirus rootstock than the other rootstocks. According to the results of analysis of variance, the rootstock effect on the index of total phenol of fruit peel and pulp and total flavonoid of fruit peel was significant at the five percent probability level (p<0.05) and only on the antioxidant capacity of the fruit peel at the statistical level of one percent (p<0.01). Also, there was no significant difference in total flavonoid traits and antioxidant capacity of fruit pulp. The highest amount of total phenolic, total flavonoid and percentage of antioxidant activity was found in the Poncirus rootstock. Also, between the fruit organs, phenolic compounds were recorded more in the fruit peel compare to the fruit pulp. The peel of orange is more exposed to ultraviolet rays and changes in environmental conditions, Therefore more secondary metabolites accumulate in that part of the plant. The highest relative expression of fruit pulp sucrose phosphate synthase1 gene was obtained in the Citrange rootstock.ConclusionThe vigour of different citrus rootstocks caused the dwrafing trees to have a higher accumulation rate of phytochemical indices than the vigorous trees. The Poncirus rootstock is suitable for fresh consumption due to the early commercial maturity of the fruit. Fruit peel rich in phenolic compounds is used for medicinal purposes. The technical knowledge of this research will be useful for citrus producers of East Mazandaran.
Postharvest physiology
Karim Manda-Hakki; Hamid Hassanpour
Abstract
The Effect of Postharvest L-phenylalanine Application on Shelf life and Physicochemical Characteristics of Sabrina Strawberry During Cold StorageStrawberry is one of the fruits known for their color, shape, aroma and taste, but it is very vulnerable to diseases and decay. One of the most important global ...
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The Effect of Postharvest L-phenylalanine Application on Shelf life and Physicochemical Characteristics of Sabrina Strawberry During Cold StorageStrawberry is one of the fruits known for their color, shape, aroma and taste, but it is very vulnerable to diseases and decay. One of the most important global challenges is food waste. Chemical compounds such as amino acids can be used as a suitable treatment to increase shelf life after harvest. In this research, the effect of L-phenylalanine (Phe) post-harvest treatment in concentrations (zero, 4 and 8 mM) and storage time (5, 10 and 15 days) on the physicochemical characteristics of Sabrina strawberry fruit during storage as the factorial experiment was conducted in the form of a completely randomized design with three replications. Based on the results, the highest color b* value in the 4 mM treatment, soluble solids (8 mM treatment), taste index (4 mM treatment), antioxidant capacity (4 mM treatment) and total phenol content (8 mM treatment)) were observed. Also, the lowest percentage of weight loss and firmness reduction were observed in the 4 mM treatment. In general, the results showed that the treatment of 4 mM L-phenylalanine can be used as the most suitable treatment to increase the post-harvest shelf life of Sabrina strawberry.Keywords: Amino acid, Fruit firmness, Titratable acid, Total phenolIntroductionOne of the most important global challenges is food waste, about 30% of the world's agricultural land is wasted. Every year, about 9.5 million tons of food is lost in the post-harvest phase of agriculture (Bishop et al., 2021). Therefore, storage technology is very important to increase shelf life, preserve nutrition and maintain the taste of fresh products (Brizsolara et al., 2020; Holler et al., 2023). Storing strawberry fruits at an inappropriate temperature after harvesting significantly increases weight loss, rotting and softening (Gol et al., 2013). Phenylalanine as an amino acid is used for the biosynthesis of all phenolic compounds through the phenylpropanoid pathway. In recent years, the application of exogenous phenylalanine has been considered for use as a biologically safe molecule to maintain the postharvest quality of many horticultural crops (Kumar Patel et al., 2020). Phenylalanine treatment has been reported to reduce the frost damage of plum fruit during cold storage by maintaining membrane integrity and improving reactive oxygen species (ROS) scavenging capacity. The treated fruit showed a higher DPPH inhibition capacity by increasing the accumulation of phenolic compounds and antioxidant enzyme activity (Sogvar et al., 2020). Aghdam et al. (2019) also reported that application of phenylalanine significantly reduced cold damage, membrane lipid peroxidation and ROS accumulation in tomato fruits during cold storage.Materials and methodsStrawberry fruits were obtained from a commercial greenhouse located in Urmia at full maturity stage. The fruits were transported to the laboratory of the Department of Horticultural Sciences in Urmia University with necessary precautions to prevent any mechanical damage to the product. The fruits were separated in terms of size and uniformity, so that the fruits were divided into 3 groups, one group as a control group and 2 groups were treated with concentrations of L-phenylalanine (4 and 8 mM). After drying the treated fruits, they were placed in zipped nylon bags and kept in a cold room for 15 days at a temperature of 3 ± 0.5 °C and a relative humidity of 90-95%. Also, three biological replicates at each time point were included in the analysis. The samples obtained at each of these times were used to evaluate skin color, titratable acidity, soluble solids, taste index, pH, weight loss, firmness, antioxidant capacity, total phenol content, and polyphenol oxidase enzyme activity.Results and discussionThe results showed that the effect of post-harvest treatment, storage time, and the interaction between them were statistically significant on all of the traits. In terms of color changes, the effect of post-harvest treatment (p≤0.05) was significant only in b* index, and the highest rate was observed in the 4 Phe treatment. The effect of storage time was also significant in a* and Chroma indices (p≤0.05) and the highest level was observed in both of these indices at day 5. The effect of storage time was also significant in TA (p≤0.01), the highest value was observed in day 10. In antioxidant capacity (p≤0.05), TSS (p≤0.05) and taste index (p≤0.01), the interaction effect between storage time and Phe treatment was significant. In antioxidant capacity, the highest percentage of DPPH inhibition was observed in day 10 and 4 Phe treatment, in TSS, the highest rate was observed on day 10 and 8 Phe treatment, and in taste index, the highest rate was observed on day 15 and 4 Phe treatment. The effect of post-harvest Phe treatment and storage period on fruit weight loss was significant (p≤0.05) and (p≤0.01) respectively, and the lowest percentage of weight loss was observed in Phe 4 and day 5. In terms of firmness and total phenol content, only the effect of Phe treatment was significant (p≤0.05) and (p≤0.01), respectively, the highest level of firmness in the 4 Phe treatment and the highest amount of total phenol content in the 8 Phe treatment were observed. In the PPO enzyme, only the effect of storage time (p≤0.05) was significant.ConclusionAccording to the obtained results, the 4 Phe treatment is the best concentration of phenylalanine to increase the shelf life of harvested strawberry fruits under cold storage.
Postharvest physiology
S. Mostafayi; M.R. Asghari
Abstract
Introduction
Apple (Malus domestica) is considered as one of the important members of the Rosaceae family and is among the most consumed fruits in the world. One of the biggest challenges for agricultural researchers is to increase the quantity and quality of food to feed the growing population, without ...
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Introduction
Apple (Malus domestica) is considered as one of the important members of the Rosaceae family and is among the most consumed fruits in the world. One of the biggest challenges for agricultural researchers is to increase the quantity and quality of food to feed the growing population, without negatively affecting the health of the soil and agricultural ecosystems. Due to the adverse effects of chemicals on human health and environmental safety, the production of organic products has been considered as one of the most important issues in food production systems. It is utilized in various forms, including fresh fruit or processed as industrial products. Based on the respiratory and ethylene production pattern, apples are classified as climacteric fruits. Metabolic activities and ripening continue after harvest, so apples have the potential to transform into highly perishable products after harvest. Post-harvest treatments are certainly not the most suitable method for preserving the shelf life and quality of fruits during the post-harvest period. Therefore, employing new and effective methods to enhance quality, control decay, and consequently extend the post-harvest life of apples appears to be essential. Organic farming, as an agricultural system to protect human health and the environment, can improve product quality and shelf life.
Materials and Methods
This study was conducted on an apple orchard (Malus domestica) in Zarabad area of Khoy city located in the northwest of Iran (with the same management and growth conditions) in 2018-2019. The experiment was conducted as a factorial in the form of a completely randomized block design in 4 replications. The experimental factors included spraying fruit trees with nano-chitosan in 3 concentrations (zero, 5 and 10 ml) and ferulic acid in 3 concentrations (zero, 0.5 and 1 mM). Apple trees in three times, the first stage in the hazelnut time. Fruit drop, the second stage 20 days after the first stage and the third stage 20 days after the second stage spraying, were sprayed in the afternoon using a Cross mark PB20 manual sprayer. The harvested fruits were sprayed according to the treatments were packed and labeled and transferred to the central laboratory of horticultural sciences of Urmia University. After 24 hours of storage at the laboratory temperature, the measurement of the studied traits started on the fruits, the control treatment in this experiment was distilled water with Tween 80 (0.1/v/v).
Results and Discussion
Compared to the control group, fruits treated with a combination of chitosan and ferulic acid exhibited a significant increase in firmness after harvest. Notably, the most effective treatment involved a combination of 10 milliliters of nano-chitosan and 1 millimolar ferulic acid, resulting in the highest level of firmness among all treatments.As a result, the combined treatment of chitosan and ferulic acid can delay the aging process by reducing the activity of enzymes involved in cell wall degradation and maintain firmness in apples, contributing to a positive effect. According to the obtained results, fruits treated with nano-chitosan and ferulic acid showed a higher soluble solid content compared to the control fruits, and this amount increased with the higher concentrations of nano-chitosan and ferulic acid. The minimum level of TA was observed in the control treatment, and the highest level was observed in the treatment with 10 milliliters of chitosan and 1 millimolar ferulic acid. The treatment with 1 millimolar ferulic acid and 10 milliliters of chitosan showed the highest percentage of TA content compared to the control. The combination of nano-chitosan and ferulic acid treatment led to a reduction in fruit juice pH, with the lowest pH observed in the treatment with 1 millimolar ferulic acid and 10 milliliters of chitosan, and the highest pH observed in the control treatment. Vitamin C is the primary water-soluble antioxidant that directly reduces damage caused by free radicals. According to the obtained results, the maximum content of vitamin C was observed in the treatment with 1 millimolar ferulic acid and 10 milliliters of chitosan. According to the obtained results, the maximum PAL enzyme activity was observed in the treatment with 1 millimolar ferulic acid and 10 milliliters of chitosan.
Conclusion
In general, the findings of the current study showed that pre-harvest treatment with nano-chitosan and ferulic acid had a positive effect on the post-harvest quality of apple fruits. The fruits treated with the highest concentration of nano-chitosan and ferulic acid exhibited the highest fruit firmness, titratable acidity, vitamin C content, PAL enzyme activity, and the lowest pH compared to the control fruits. These results indicate that nano-chitosan and ferulic acid treatment can be proposed as a promising and healthy method for improving the post-harvest quality of apple fruits.
Postharvest physiology
Z. Pakkish; S. Mohajerpour; S. Saadati
Abstract
Introduction
Fresh fruits and vegetables are physiologically active and perishable after harvest. Continued metabolic processes such as transpiration or respiration may significantly affect their quality and thus shorten their useful life. Since keeping at low temperatures and without freezing for ...
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Introduction
Fresh fruits and vegetables are physiologically active and perishable after harvest. Continued metabolic processes such as transpiration or respiration may significantly affect their quality and thus shorten their useful life. Since keeping at low temperatures and without freezing for a long time effectively reduces the physiological activity of the products, it can be used as a strategy to maintain the quality of the products and increase their life after harvesting. Among the most economically important tropical fruits, ripe green bananas are very sensitive to cold and when stored below the threshold temperature, they show all the symptoms of frost damage. While banana cultivars, maturity stage, and ripening all influence cold sensitivity, there's a growing interest in extending the shelf life of produce using natural, plant-friendly compounds. Gamma-aminobutyric acid (GABA), a naturally occurring four-carbon, non-protein amino acid found in plants, animals, and bacteria, is a promising candidate in this area.Abiotic stresses such as cold, heat, drought, ultraviolet rays and low oxygen can cause the accumulation of GABA in plants. Generally, the purpose of this research was to investigate the effect of gamma-aminobutyric acid treatment to improve freezing and antioxidant properties of Cavendish banana at 5 degrees Celsius for 24 days in 90% relative humidity.
Materials and Methods
Cavendish banana fruits (Musa acuminata cv. Cavendish) at the time of commercial maturity (ripe green) were obtained from a banana garden in Kerman and immediately transferred to the horticultural science laboratory of Shahid Bahoner University, Kerman. Healthy and uniform fruits were selected in terms of size, shape, color, and degree of ripening, and after washing with water and drying them, frost tolerance, malondialdehyde, and antioxidants were measured for zero day. GABA (Sigma-Aldrich, USA) required after weighing was dissolved in water and prepared in two concentrations of 2.5 and 5 mM. The fruits were divided into three groups of 54 and each repetition included 18 fruits. The first and second groups were immersed in GABA solution of 2.5 mM and 5 mM for 5 minutes, respectively. The third group was immersed in distilled water for 5 minutes and was used as a control (Khaliq et al., 2023). Each treatment was repeated three times. Then, all the fruits were dried in the air for one hour and kept for 24 days at 5 degrees Celsius and relative humidity of 85-90%. Biochemical observations were measured on days 0, 4, 8, 12, 16, 20 and 24 of storage.
Results and Discussion
The results of this research showed that frost damage gradually increased during the storage period and the control fruits showed significantly more frost damage symptoms than the fruits treated with GABA. GABA treatments of 2.5 and 5 mM at the end of the storage period reduced the amount of frost damage by 55.64 and 69.95%, respectively, compared to control fruits. As shown in Figure 1b, MDA content as an index of membrane lipid peroxidation in the control and GABA-treated fruit showed an upward trend, which was associated with the destruction of banana fruit membrane under cold stress. Compared to control, banana fruits treated with GABA showed lower MDA accumulation during the entire storage period at 4 degrees Celsius. On the last day of storage, GABA treatment with a concentration of 2.5 mM and 5 mM reduced the amount of MDA in banana fruits by 30.99% and 59.80%, respectively, compared to the control. Post-harvest treatment with GABA reduced frostbite, ion leakage and MDA levels in banana fruits, thereby maintaining fruit quality during low temperature storage. GABA treatment increased the activity of catalase (CAT), ascorbate peroxidase (APX), peroxidase (POD) and superoxide dismutase (SOD) enzymes in banana fruit compared to the control under low temperature storage. The activity of antioxidant enzymes CAT, APX, POD and SOD increased significantly until the 20th day of storage at low temperature, especially in the 5 mM GABA treatment compared to the other two treatments, and then decreased slightly at the end of the storage period. An increase in the concentration of oxygen free radicals, including hydrogen peroxide, leads to an increase in catalase enzyme activity. Catalase enzyme is often present in the peroxisome and causes the decomposition of hydrogen peroxide into water and oxygen. The specific activity of catalase enzyme increased during cold storage, especially in GABA treatments, so it seems that this enzyme is an efficient scavenger for removing hydrogen peroxide and thus causes better protection of cells against peroxidation. In the ascorbate-glutathione cycle, the ascorbate peroxidase enzyme reduces the amount of hydrogen peroxide by using ascorbate as an electron donor. In the present study, the activity of ascorbate peroxidase enzyme in GABA treatment was significantly higher than the control, which indicates the importance of the role of ascorbate peroxidase in plant tissues against oxidative damage. Guaiacol peroxidase enzyme is another antioxidant enzyme that decomposes hydrogen peroxide into water and oxygen. Peroxidase enzyme plays a role in the oxidation of precursors of phenolic compounds, lignin production, and removal of free radicals. The activity of peroxidase enzyme showed a similar trend in all three treatments, although its activity in GABA treatments was more than the control. Therefore, this enzyme effectively eliminated free radicals in banana fruits. In confirmation of these findings, it was reported in research that the activity of peroxidase enzyme increased in fir cuttings during the cold period. In research, post-harvest treatment of GABA with a concentration of 5 mM reduced frostbite and increased the activity of antioxidant enzymes such as CAT, APX, POD and SOD in peach fruits.
Conclusion
The results of this research showed that the applied post-harvest treatments reduced the signs of frostbite and preserved the antioxidant properties of banana fruits. Among the treatments, 5 mM concentration of GABA was the most effective treatment in the storage period. Therefore, GABA treatment can be used as a practical solution to reduce frostbite and preserve the antioxidant properties of Cavendish bananas during long-term storage.
Postharvest physiology
Behzad Kaviani; Mohammad Reza Safari Motlagh; Sara Hataminejad
Abstract
Introduction Chrysanthemum (Chrysanthemum morifolum L.) is one of the most important cut flowers in the world, which currently ranks second in the world after rose in terms of economy and cultivation. Stem end blockage and water stress are two problems in decreasing the vase life of chrysanthemum ...
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Introduction Chrysanthemum (Chrysanthemum morifolum L.) is one of the most important cut flowers in the world, which currently ranks second in the world after rose in terms of economy and cultivation. Stem end blockage and water stress are two problems in decreasing the vase life of chrysanthemum cut flowers. Cut flowers undergo physiological and biochemical alterations which often lead to an early senescence. Steps to delay the senescence process rely on consideration of many aspects of handling process particularly the preservative solution that will influence the quality and longevity of the flowers. Many flowers are harvested before they are fully developed, to ensure a long postharvest life and to minimize mechanical damages which may occur during handling. Many researches have been performed to prolong the vase life of chrysanthemum cut flowers with different treatments like essential oils, organic acids and nanoparticles. Essential oils are aromatic oily liquids obtained from some aromatic plant materials. In vase solution, microorganisms cause stem obstruction and accelerate the aging of petals. Microorganisms and their toxic products restrict water uptake by blocking the end of the stem. Water balance, which is an important factor in maintaining the quality and longevity of cut flowers and the inability to uptake water are the main causes of senescence. The presence of disinfectants in the vase solution prevents the growth of microorganisms, protects the vessels against disintegration, and ultimately increases the vase life. Most of nanoparticles have antibacterial effects and their application in vase solution hinders microorganism growth and vascular blockage. Nanoparticles have high area-to-volume ratio, high efficiency, and low toxicity. Some nanoparticles penetrate into the cells of bacteria, disrupt their respiration chain, and cause disorder in their cell division, thereby killing them. They also inhibit the accumulation of bacteria in vase solution and stem end of cut flowers. Various studies have reported the positive impact of nanoparticles on decreasing microbial load, reducing transpiration from leaf surface, and preserving water uptake. Studies on postharvest longevity of chrysanthemum cut flowers using these compounds is low. Therefore, the aim of the present study was to evaluate the effect of orange spring essential oil, fulvic acid and cupper nanoparticles on vase life and some physiological parameters of chrysanthemum cut flowers. Materials and MethodsThe experiment was performed based on randomized completely design with three replicates in order to investigate the effect of different levels of fulvic acid (50, 100 and 150 mg l–1), orange spring essential oil (10, 30 and 50%) and copper nanoparticles (5, 10 and 20 mg l–1) in comparison to control (distilled water + 3% sucrose + 30 mg l–1 8-hydroxyquinoline sulphate) on postharvest parameters of chrysanthemum cut flowers. Measured parameters included vase life, solution uptake, vase solution bacterial population, stem end bacterial population, decreasing the brix degree, decreasing fresh weight, dry matter, total chlorophyll content, carotenoid content, protein content, and peroxidase and superoxide dismutase activity. Data were analyzed by SPSS statistical software package and means were compared with the LSD test at the probably level of 95%. Results and DiscussionAccording to the obtained results, the effect of treatments on improving the quality characteristics of chrysanthemum cut flowers after harvest was significant. Results showed that the high vase life (16.33-17.00 days) was obtained with all three copper nanoparticles concentrations. The vase life of chrysanthemum cut flowers was extended to 17 days by the addition of 20 mg l–1 copper nanoparticles in preservative solution in compared to control with 14 days’ vase life. Least solution bacteria colonies was obtained through the use of 5 mg l–1 copper nanoparticle. On the other hand, least stem end bacteria colonies was obtained using 10 and 30% orange spring essential oil. Solution uptake in these treatments was high, too. The effects of different treatments on some other physiological traits and antioxidant enzymes activity were measured. Many studies have been carried out on the effect of essences (herbal extracts) as antimicrobial agents on prolonging the vase life of cut flowers. In most of these studies, these essences could prolong postharvest life. Essences have been studied with the intension of incorporating them into integrated pest management to avoid or reduce the use of synthetic bactericides and fungicides. They also have antioxidant properties. Application of herbal extracts improved water absorption in rose cut flowers by preventing the vessel obstruction. The above results are similar to the results of this study. In most cases, when the cut flowers were treated with nanoparticles, they exhibited longer vase life, higher water uptake, and lower stem-end bacteria than the control flowers.
Postharvest physiology
K. Hosseinzadeh Moghaddam; B. Kaviani; D. Hashemabadi; Sh. Sedaghathoor; M.R. Safarimotlagh
Abstract
IntroductionKiwi (Actinidia deliciosa) is rich in minerals, vitamins and antioxidants. Kiwi fruit is sensitive to ethylene and has high perishability. There are some physical and chemical methods to delay aging and maintain postharvest quality of fruits. Light irradiation is a physical and pollution-free ...
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IntroductionKiwi (Actinidia deliciosa) is rich in minerals, vitamins and antioxidants. Kiwi fruit is sensitive to ethylene and has high perishability. There are some physical and chemical methods to delay aging and maintain postharvest quality of fruits. Light irradiation is a physical and pollution-free method that has been reported to be effective in controlling fruit decay and increasing its shelf life. Sodium nitroprusside (SNP) acts as an important signal in some physiological activities of the plant. SNP improved the quality and durability after fruit harvest in some fruits.Amino acids are effective in delaying the aging process and increasing the postharvest life of horticultural crops. Arginine plays an important and vital role in plant growth and development processes. The positive effect of arginine in increasing the shelf life of some fruits has been reported. The aim of this study was to increase the shelf life and quantitative and qualitative characteristics of ‘Hayward’ kiwi fruit after harvesting with the use of blue light, SNP and arginine. Material and MethodsHealthy and uniform fruits were selected and exposed to blue light (6, 12 and 24 h) at a wavelength range of 470 nm by LED lamps, SNP (0.5, 1 and 2 mM) and arginine (0.5, 1 and 2 mM). The experiment was performed in a completely random design with 10 treatments in 3 replications with 30 plots and 10 fruits per plot. After immersing the fruits at different levels of arginine, SNP and distilled water (control treatment), the surface of the fruits was dried and then sterilized. The fruits were monitored daily and their quantitative and qualitative properties were recorded during the experiment. Parameters of shelf life, tissue firmness, flavor index, loss of fresh weight, proline, ionic leakage, malondialdehyde (MDA), and dry matter, as well the activity of ascorbate peroxidase (APX), peroxidase (POD) and superoxide dismutase (SOD) enzymes were measured. Analysis of data obtained from sampling during the experimental period and laboratory were performed using SPSS statistical software and comparisons of means was done based on LSD statistical test. Results and DiscussionThe results showed that SNP at a concentration of 2 mM caused the highest shelf life (117.20 days) and the highest proline content (80.14 mg/kg) in kiwi fruits. The reason for this increased shelf life may be that SNP delays ethylene production process by activating the genetic and biochemical mechanisms, thus increase the postharvest life of ethylene-sensitive products. The highest firmness (4.56 kg/cm2) and the lowest fresh weight loss (1.26%) was obtained in fruits treated with 12 h of blue light. Some of the most important causes of this finding are that blue light delays the peak time of ethylene production, and as a fungal agent, reduces fruits decay after harvesting. The data showed that 12-h irradiation of blue light and 2 mM SNP caused a significant increase in the amount of antioxidant enzymes (SOD, POD and APX) of kiwifruit. Other traits such as flavor index, dry matter content, ion leakage and malondialdehyde were also measured. Blue light treatment can effectively reduce the decay of many fruits during postharvest storage. The study on kiwifruit showed that the qualitative treatments of different lights on various cultivars at different times had a significant effect on some physiological, morphological and gene expression traits. LED irradiation was found to be a suitable method for improving the quality of nutrients and the quality of flavor after harvest of some fruits. SNP was a good treatment to maintain fruit quality and improve disease resistance in kiwi cultivar ‘Bruno’ during storage. Fruits treatment with arginine is a promising technology to reduce cold and brown damages by stimulating the activity of antioxidant enzymes. Plant resistance to environmental stresses due to the use of arginine is in order to the effect of this substance on polyamine accumulation through increasing arginine decarboxylase and ornithine decarboxylase enzymes and increasing proline accumulation by enhancing ornithine amino-transferase enzyme activity as well as increasing nitric oxide through increasing the activity of nitric oxide synthase enzyme. Quality of kiwi fruit decreases during storage due to rapid softening and contamination with some fungi. In this study, effective treatments were used to reduce these complications. Overall, the results of this study showed that 2 mM SNP caused the highest shelf life. The highest firmness and the lowest fresh weight loss were observed in fruits treated with 12 h blue light. 12-h irradiation of blue light and 2 mM SNP caused a significant increase in the antioxidant enzymes of kiwifruit.
Postharvest physiology
P. Hayati; M. Hosseinifarahi; Gh. Abdi; M. Radi; L. Taghipour; P. Assar
Abstract
IntroductionThe Peruvian Groundcherry (Physalis peruviana L.) is a perennial plant that is native to the South American regions and belongs to the Solanaceae family. The harvested fruits are vulnerable to both biotic and abiotic stresses, which can trigger unfavorable physiological and biochemical changes. ...
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IntroductionThe Peruvian Groundcherry (Physalis peruviana L.) is a perennial plant that is native to the South American regions and belongs to the Solanaceae family. The harvested fruits are vulnerable to both biotic and abiotic stresses, which can trigger unfavorable physiological and biochemical changes. As a result, the quality and marketability of the product may decrease by the time it reaches the consumer. The fruit of the Peruvian Groundcherry has a high water content and is sensitive to ethylene, causing rapid ripening with a high respiration rate, making it highly perishable. To ensure quality maintenance after harvest, various postharvest treatments are being studied; however, some methods may not be practical due to low customer preference or lack of effectiveness verification. Therefore, alternative treatments need to be found to prolong shelf life and reduce postharvest losses. Currently, environmentally friendly technologies and treatments are recommended. The aim of this study was to investigate the effects of γ-Aminobutyric acid (GABA) postharvest treatment on the respiration rate, antioxidant activities, and fruit quality of the Peruvian Groundcherry during 21 days of storage, addressing a research gap in this area.Materials and MethodsHandpicked Peruvian Groundcherry fruits were taken from a commercial greenhouse located in Fars province, Iran. The fruits were picked at two stages of maturity based on their color, which was either yellowish green or orange. Following the harvest, the fruits were taken to a horticulture laboratory where they were assessed for appearance, size, color, and any damages. The experimental design was factorial based on a completely randomized design with three replications, each containing 25 fruits. Experimental factors included the GABA concentration (0, 5, 10 and 15 mM), storage time (7, 14 and 21 days) and fruit maturity stage based on color at harvest (yellowish green and orange). Following dip treatments in GABA solutions, fruits were packed in plastic clamshells measuring 20×5×10 cm3 and with a hole ratio of 3%. Fruits were stored at a temperature of 15 ◦C for 21 days, and their quality characteristics and respiration rate were evaluated on a weekly basis.Results and DiscussionThe findings indicated that both groups of treated fruits had a slower increase in respiration rate and lower final respiration rate compared to the control group. The effect of different concentrations of GABA on the final respiration rate of fruits was similar for each stage of fruit maturity. During the storage period, the changes in total soluble solids and total acids of the treated fruits were less than the control group. At the end of the storage period, yellowish green fruits treated with 10 and 15 mM GABA had the lowest amount of total soluble solids; orange fruits had the lowest amount with 15 mM GABA treatment. GABA concentrations had a similar effect on total acids retention of yellowish green fruits, but 15 mM GABA treatment was more effective for orange fruits. Ascorbic acid content and phenylalanine ammonia-lyase enzyme activity were consistently higher in treated fruits than in the control group. In green fruits treated with GABA concentrations, the amount of ascorbic acid increased significantly and continuously, with no significant difference between treatments at the end of storage period. Orange fruits showed a significant increase until the second week of storage, followed by a non-significant decrease. Higher amounts of ascorbic acid in orange fruits were detected by applying higher GABA concentrations. Both groups of fruits had significantly higher amounts of total phenol, carotenoid, and antioxidant capacity in response to increasing GABA concentration, while the minimum amount of these compounds during the storage period was related to the control group. However, orange-colored fruits were more sensitive to treatments compared to yellowish green fruits.ConclusionsThe results of the present study indicate a positive effect of postharvest GABA treatment on reducing respiration rate, improving antioxidant activities, and maintaining the quality and nutritional value of Peruvian groundcherry fruit during a 21-day storage period. Considering the global preference and demand among governments and consumers to use environmentally-friendly treatments of biological origin that pose no risk to human health, we recommend the use of GABA treatment for optimal storage of Peruvian groundcherry fruit. Finally, it is recommended to assess the efficacy of GABA or other safe and environmentally-friendly postharvest treatments on the quality and shelf life of other valuable horticultural commodities.
Postharvest physiology
S. Shirani Rad; M, Sayyari; M.A. Zolfigol
Abstract
Introduction
Horticultural waste is one of the top challenges these days. As the population increases, food loss and waste, which has a serious impact on the environment and human health. Horticultural waste is rich in nutrients, polysaccharides and antimicrobial compounds that can be used in the ...
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Introduction
Horticultural waste is one of the top challenges these days. As the population increases, food loss and waste, which has a serious impact on the environment and human health. Horticultural waste is rich in nutrients, polysaccharides and antimicrobial compounds that can be used in the production of edible coatings. Edible coatings protect fruit from nutrient and mineral loss and extend shelf life. Strawberry fruit is one of the commercial horticultural crops because it contains important and diverse sources of natural antioxidants, flavonoids, phenolic acids and minerals. However, the fruit is highly perishable due to its high respiratory rate and metabolic activity, soft texture and lack of protective skin, which can lead to moisture loss, mechanical damage and fungal damage during harvesting, handling and packing. It is estimated that approximately 30% of strawberry fruit is wasted during the post-harvest stage before reaching the consumer. Therefore, reducing the destruction rate of its quantitative and qualitative properties is considered one of the most important challenges. Plant Extract Edible Coating (PEEC) is an environmentally friendly edible coating. Like other edible coatings, PEEC is a thin layer of material applied to the surface of a product. Pomegranate peel extract has biological activities such as antibacterial, antiviral, antioxidant, anti-inflammatory, and antifungal. This extract was used alone or in combination with other post-harvest treatments to preserve product quality. Tomatoes contain secondary metabolites called steroidal glycoalkaloids. These compounds primarily act as crop protection agents against insects, bacteria, parasites, viruses and fungi. This study evaluated the efficacy of pomegranate peel extract and tomato seedlings in maintaining strawberry fruit quality during cold storage and reducing post-harvest waste.
Materials and Methods
Healthy fruits with uniform size, shape, and color were carefully selected from strawberries harvested from an orchard in Kamyaran, Kurdistan. We conducted a study to investigate the effects of coating these strawberries with pomegranate peel extract (1%) and tomato seedling extract (1%) on their physiological and qualitative responses. The fruits were coated with the respective plant extracts and subsequently stored at 4 ± 1°C and 90–95% relative humidity for a duration of 15 days. Strawberry quality was analyzed on the first day of storage and on days 5, 10 and 15. Various qualitative factors such as weight loss, firmness pH, total soluble solids content, titratable acidity, total phenolic content, total anthocyanin content, total antioxidant activity, total flavonoid content, ascorbic acid, color and decay severity were evaluated. Statistical analysis of the data was performed using SAS (version 9.4) and mean comparisons were performed using the Duncan multiple range test.
Results and Discussion
The study on the property retention and long-term cold storage time of pomegranate peel and tomato seedling extracts coating showed that a concentration of 1% of the extracts used have a significant effect on strawberry fruit quality and phytochemical parameters. It was shown to have a significant impact on strawberry fruit quality and phytochemical parameters, improving compared to the control treatment during cultivation. Weight loss increased with all treatments during storage. After 5 days of storage, no differences between treatments were discernible, but at the end of storage all treatments showed a clear decrease in fruit weight. Pomegranate peel and tomato seedling extracts reduced weight loss by 12% and 15%, respectively, while the control significantly reduced weight loss by 26%. Despite the decrease in fruit tissue firmness during storage, the firmness of the plant extract-coated fruit was maintained and significantly different from the control. PH remained at low levels for all treatments compared to controls. The total acid and total soluble solids content of the fruit are affected by the treatments considered, the storage, and the combination of times and treatments. The total content of phenolic compounds reached 223 mg gallic acid and 236 mg gallic acid per 100 g fresh weight on the 10th and 15th storage days after treatment with pomegranate peel extract. For tomato seedling extract, this corresponds to 207 mg and 182 mg gallic acid per 100 g fresh weight. The total anthocyanin content in all fruits decreases with increasing storage time, but this trend increases after 10 days when tomato seedlings are treated. In all fruits, various treatments increase anthocyanin levels throughout the storage time. ANOVA of antioxidant activity showed no significant effects on treatment-independent and chronotherapy-interaction effects, while the time-independent effect showed a significant effect at 5%. The greatest antioxidant activity is associated with pomegranate peel extract. The frequency of this feature in treatment decreased with increasing storage time. During the treatment period, there was a progressive increase in antioxidant activity from the 10th to the 15th day, demonstrating a significant difference compared to the beginning of the treatment. Average comparison results revealed a slight but significant difference in the treatments concerning flavonoid content. Analysis of variance and comparison of mean results indicated a significant difference in ascorbic acid content during storage among the different treatments. Color indices remained consistent across all treatments. The 15-day shelf life of strawberries was assessed, and the treatments employed effectively reduced decay rates during storage. Upon analysis, it was determined that the 1% concentration of pomegranate peel extract exhibited the highest efficacy in suppressing the severity of spoilage.
Conclusion
Residues from various agricultural sectors have a variety of uses, including their properties as preservatives that extend the shelf life of perishable fruits and enhance the nutritional value of fruits and vegetables. Replacing plant extracts with synthetic compounds can play an important role in preserving the characteristics and quality of strawberry fruits during storage. Based on the results of this study, an edible coating containing plant extracts from pomegranate peel and tomato seedling as natural preservatives was used to extend the shelf life and enhance the nutritional quality of strawberry fruits during cold storage. Finally, using natural compounds such as plant extracts from agricultural waste is a safe and healthy way to manage and preserve the properties of post-harvest agricultural products.
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.
Postharvest physiology
P. Karimi Tazeiji; S. Rastegar; H. Hasanzadeh Khankahdani
Abstract
Introduction
Date fruit (Phoenix dactylifera L.) is one of the oldest known fruit crops and is considered as an important component of the diet in many Middle Eastern and North African countries. The fruit of date is nutritious, which is incredibly rich in carbohydrates, minerals, dietary fibers and ...
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Introduction
Date fruit (Phoenix dactylifera L.) is one of the oldest known fruit crops and is considered as an important component of the diet in many Middle Eastern and North African countries. The fruit of date is nutritious, which is incredibly rich in carbohydrates, minerals, dietary fibers and amino acids. Dates are one of the most important tropical fruits that play an important role in the country's economy. Among the date palm cultivars in Hormozgan province, Piyarom is one of the most commercial cultivars.
Recent studies by scientists have shown that the use of chemical compounds, in addition to environmental hazards, will cause various diseases in consumers due to the residual transfer of toxins to their bodies. Therefore, the management orientation of food preservation methods has moved towards reducing and eliminating chemicals and determining suitable alternatives, so that a certain time frame was set for the removal of some of the most important tobacco toxins.
In recent years, attention has been paid to aloe vera gel as a coating layer for fruits and vegetables to maintain their storage quality, and because it has no smell or taste, eating it does not pose a problem for humans and it is even good for health. L-arginine is one of the 20 major amino acids of living cells, which is a semi-essential amino acid in the human body. L-arginine and D-arginine are natural forms of common isomers of this type of amino acid.
The aim of the present investigation was the assess the effect of L-Arginine and Aloe vera gel edible coating on maintaining the external properties and the quality of semi-dried date fruit cultivars including Piyarom during storage.
Material and Method
The experiment was conducted as a factorial arrangement in a completely randomized design. The first factor was including seven treatments consisting of control, L-Arginine (1, 2, and 8 mM) and Aloe vera gel (25, 50, and 75%) and the second factor included storing (sampling) time for 9 months. In every measurement, the different attributes were evaluated such as weight loss percent; TSS; total acid; total phenol; flavonoid; color indexes including L*, a*, and b*; and antioxidant capacity. The level of antioxidant activity was evaluated by antioxidant agents by the method described by based on the trapping of free radicals of 2, 2-diphenyl 1-picryl hydrazyl (DPPH). DPPH solution was well combined with the methanol extract by means of a vortex and was incubated in the dark for 30 min. Then the absorption rate was read at 517 nm using a spectrophotometer. The color was determined using a colorimeter (Minolta, CR-400, Japan) after different months of storage. All measurements were done in triplicates. L* (100=white, 0=black), a* (–green, +red) and b* (–blue, +yellow) values were obtained at 400-700 nm range. The assay of the total phenol content was performed by applying the Folin–Ciocalteu colorimetric procedure. The total soluble solid (TSS) content of the fruit juice obtained for each replicate was determined using a hand-held refractometer Atago (Atago Co. Japan) at 25 °C; the results are expressed as % (°Brix). Titratable acidity (TA) was measured by titrating diluted juice with 0.1 N NaOH to a phenolphthalein end-point (pH 8.1-8.3). The results are expressed as citric acid %.
Results and Discussion
Based on the results, the treatments of Aloe vera gel and L-Arginine had significant effect on the quantitative and qualitative traits of Piyarom date fruits during storage. Storing time had significant influence (p<0.01) on the all parameters so that by passing storage time, the parameters including L*, a*, b*, a weight loss percent significantly increased and the parameters such as phenol, flavonoid and antioxidant significantly decreased. In the Piyarom cultivar, the treatments had significant effects on a*, b*, weight loss percent, phenol, flavonoid, and antioxidant, but it had no significant influence on TSS and total acid, so that the highest a* and b* color indexes was observed in the use of L-Arginine 1 mM, the greatest phenol and flavonoid in the application of L-Arginine 2 mM, the lowest weight loss percent in the use of Aloe vera gel 25 and 75%, respectively.
Conclusion
According to the results, 1 mM L-arginine treatment and 75% Aloe vera gel had a more effective role in maintaining the storage quality of Piyarom dates. The use of these treatments requires more extensive research on soft and dry dates.
Postharvest physiology
S. Shiukhy Soqanloo; M.A. Gholami; Y. Ghasemi
Abstract
Introduction
Confronting the crisis of water scarcity and the looming challenge of dwindling water resources is undeniably a grave concern. Consequently, the focus of agricultural science researchers has shifted towards the utilization of wastewater. One of the notable advantages of incorporating wastewater ...
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Introduction
Confronting the crisis of water scarcity and the looming challenge of dwindling water resources is undeniably a grave concern. Consequently, the focus of agricultural science researchers has shifted towards the utilization of wastewater. One of the notable advantages of incorporating wastewater in agriculture is the potential to curtail the expenses associated with procuring irrigation water and employing chemical fertilizers.
Materials and Methods
Sari has a longitude and latitude of 53°01′ E and 36°33′ N, respectively, and its weather conditions are humid according to De-marten's climate classification. Its elevation is 21 above sea level and average annual temperature and precipitation, are17.9 ºC and 650 mm, respectively). In order to evaluate the effect of water stress and urban wastewater on the concentration of heavy metals, yield and some characteristics of basil, an experiment in a factorial format based on a completely randomized design with experimental treatments including; The first factor is the source of irrigation (I): [treated wastewater (TWW) and well water (WW)], and the second factor is water stress (S): [the lowest stress (S1, S2), medium stress (S3, S4) and severe stress (S5, S6)] were performed in three replications at the research farm of Sari University of Agricultural Sciences and Natural Resources (SANRU), Iran. Finally, the obtained data were analyzed using ANOVA of SAS9.2, and the SNK post hoc test was employed to compare treatment means.
Results and Discussion
Based on the findings, Irrigation with wastewater increased plant height, stem diameter, fresh and dry weight compared to irrigation with well water. So that the highest plant height, stem diameter, wet and dry weight were related to irrigation with wastewater with 44.3 cm, 3.1 mm, 8.5 and 3.3 g, respectively. Also, the effect of using treated wastewater on chlorophyll a, chlorophyll b, total chlorophyll and carotenoids was significant (P ≤ 0.01). while it did not have significant effect on flavonoid, phenol and antioxidant activity. In the lowest stress, especially the S1 level, the amount of chlorophyll a, chlorophyll b, total chlorophyll, carotenoid, flavonoid, phenol and antioxidant activity compared to the S6 level decreased by 63.3, 32.8, 40.7, 45.8, 46.3, 55.5, and 9.8%, respectively. while the highest amount of plant height, fresh weight, dry weight and stem diameter at the S1 level was observed with 48.6 cm, 11.5 g, 3.51 g and 3.4 mm, respectively. The result shown that the Pb and Cd concentration in basil under irrigation with wastewater was 3.4 and 2.5 mg.kg-1, respectively, which increased by 13 and 9% compared to well water. Water stress affected the Pb and Cd concentration, but the Cr and Ni concentration did not change significantly. The highest Pb and Cd concentration was related to high stress level S5 and medium stress level S4 and the lowest level was observed in the lowest stress levels (S1 and S2). Also, the results showed that the Pb and Cd concentration was affected by the interaction effect of irrigation source and water stress. Thus, the highest Pb concentration was observed in irrigation with wastewater and water stress levels S4 and S5 with 3.41 and 3.40 mg.kg-1, respectively, and the lowest was related to irrigation with well water and water stress level S1 with 2.2 mg.kg-1. The highest Cd concentration was related to irrigation with wastewater and stress levels S4 and S5 with 2.6 and 2.5 mg/kg, respectively, and the lowest amount were observed in well water irrigation and stress levels S1 and S2, with 1.51 and 1.50 mg.kg-1, respectively. while the Cr and Ni concentrations did not significant.
Conclusion
Based on the findings of this research, irrigation with treated wastewater and application of water stress had significant effect on the morphological and phytochemical characteristics of basil. while the use of treated wastewater was ineffective on the biochemical characteristics of basil and only water stress conditions affected their levels. The Pb and Cd concentration in basil increased under the influence of irrigation with wastewater and water stress levels. But this increase was lower than the standards authorized reported by the researchers and did not cause much concern. the results shown that the water stress levels S4 and S5 can be considered appropriate in water efficiency and recommend the use of treated wastewater in basil irrigation considering the authorized standards.
Postharvest physiology
M. Rahemi; M.H. Nazaran; S. Abolghasemi; S. Sedaghat; M. Zare
Abstract
Introduction
Low temperature storage is the most important method used to preserve harvested products. Keeping products at low temperatures, above the freezing point up to 10 degrees Celsius, can cause frost damage in fruits and vegetables, especially tropical and subtropical products. The use of heat ...
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Introduction
Low temperature storage is the most important method used to preserve harvested products. Keeping products at low temperatures, above the freezing point up to 10 degrees Celsius, can cause frost damage in fruits and vegetables, especially tropical and subtropical products. The use of heat treatments as safe, organic and alternative physical methods is increasing, these treatments are used to maintain the quality after harvesting and also to prevent frostbite of garden products. Also, one of the recommended methods to reduce fruit waste is to increase the calcium concentration of the fruit by using calcium solutions. Calcium is one of the most important mineral elements that is involved in determining the quality of the fruit and its shelf life. Studies conducted on the use of nano fertilizers in some species of fruit trees has shown their potential role in improving the yield of the product and the physical and chemical properties of the fruitThis study was conducted to investigate the effect of postharvest treatments of calcium chloride and nano chelated calcium fertilizers on chilling injury and physiological characteristics of local orange fruits stored at 2 ±0.5° C and 85% relative humidity for 60 to 120 days.
Materials and Methods
In this research, orange fruits of the local cultivar Citrus sinensis at the stage of commercial maturity based on the taste index (10TSS/TA⋍) were prepared from Darab city of Fars province and transferred to the Physiology Laboratory of Horticultural Sciences Department of Shiraz University. Then the fruits were disinfected with 2% sodium hypochlorite and washed with distilled water. Treatments included calcium chloride and nano chelated calcium fertilizers at different concentrations of zero, 3 and 6 dissolved in cold water (20°C) and hot water at 45 °C for 25 and 15 min, respectively. Sampling was done on days 60 and 120. To simulate shelf life conditions, before measuring the parameters, the fruits were kept at laboratory temperature for two days. In this research, the changes in fruit tissue firmness, freezing index, weight loss percentage, soluble solids, total acidity, ascorbic acid, ion leakage, potassium ion leakage, malondialdehyde, calcium content of fruit skin and flesh, fruit color, catalase enzymes and peroxidase were measured. Data analysis was done using SAS software version 4.9 and comparison of averages was done by LSD test at 5% probability level.
Results and Discussion
There was a significant difference between nano chelated calcium and calcium chloride in calcium enrichment in pulp and fruit skin Calcium chloride and nano chelated calcium treatments dissolved in hot water reduced weight loss, soluble solids content, acidity, ascorbic acid, ion leakage and malondialdehyde and the activity of the antioxidant enzymes catalase and peroxidase. Nano chelated calcium increased calcium content by 44% in fruit skin and up to 41% in fruit pulp compared to calcium chloride. Nano chelated calcium 3 and 6 % showed more stability in fruit weight (159 and 400%, respectively) compared to calcium chloride after two months of storage. After 60 and 120 days of storage, the content of ascorbic acid in fruits treated with 6 nano chelated calcium was 73% higher than calcium chloride. Nano chelated calcium 3 % compared to calcium chloride prevented 39.6 of potassium ion leakage during 60 days of storage. The amount of ascorbic acid in the 3% and 6% nano calcium treatment and the tissue hardness in the 3% nano calcium chelate treatment after two months of storage were estimated to be higher than the control and calcium chloride. Calcium nano chelate 6% improved the calcium content of fruit flesh and skin due to increased permeability. Warm water pretreatment with calcium compounds is an efficient and recommendable treatment for the preservation of orange fruits in cold storage conditions due to the improvement and reduction of the severity of the increase in indicators related to the occurrence of frost damage in the skin of fruits.
Conclusion
One of the primary concerns during storage is the loss of fruit weight. Calcium nano chelate, in comparison to the control and calcium chloride treatments, exhibited the least weight loss over the two months of storage. This is attributed to the critical role of calcium in influencing the shelf life of fruits. It was observed that immersing fruits in calcium compounds dissolved in hot water and utilizing 6% nano chelated calcium had a significant positive impact on enhancing and preserving the quality of orange fruits during cold storage.
Postharvest physiology
H. Soleymani; M. Aelaei; M. Arghavani
Abstract
Introduction
Rose is one of the important cut flowers, which has different types. Extending the vase life of rose-cut flowers is very important in the floriculture industry. Every year, due to the lack of proper storage conditions after harvesting, the efficiency of rose production decreases. ...
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Introduction
Rose is one of the important cut flowers, which has different types. Extending the vase life of rose-cut flowers is very important in the floriculture industry. Every year, due to the lack of proper storage conditions after harvesting, the efficiency of rose production decreases. Therefore, always using materials that help increase the shelf life of cut flowers is valuable. Today, substances that improve the quality of cut flowers are very important. They include materials such as calcium and silver. Nanoparticles are materials with sizes smaller than 100 nanometers. On the other hand, the important role of calcium and silver in improving quality of the cut flowers is interesting for scientists. In this research, the effect of pre-harvest application of calcium nanoparticles along with the post-harvest application of silver nanoparticles on the morpho-physiological characteristics of rose cut flowers (CV: Classic Cezanne) was investigated.
Material and Methods
The current research was carried out during the year 2021 in a commercial rose production greenhouse in Nazarabad city. calcium nanoparticles with different concentrations (0, 5 and 10 mg.L-1) were sprayed on rose bushes every ten days (two months before harvest). After harvesting the flowers and transferring them to the laboratory, silver nanoparticles were added to the flower preservation solution at different concentrations (0, 5 and 10 mg.L-1). After harvesting, the traits (vase life, flower diameter, fresh weight, vase solution uptake, total protein, malondialdehyde and superoxide dismutase) were evaluated on the treated flowers (on days 0, 4, 8 and 12). Experiment was performed as factorial based on completely randomized design, included 9 treatments with 3 replications.
Results and Discussion
Based on the results of analysis of variance of treatment with calcium nanoparticles and silver nanoparticles for the quality of shelf life at the 1% level of Duncan's test, it showed a significant difference. Also, based on the results, the highest amount of vase life is related to the treatment of calcium nanoparticles with a concentration of 10 mg.L-1 with the silver nanoparticle treatment in the time after harvesting was at concentrations of 5 and 10 mg (11 days) and the lowest amount was related to the control treatment (7 days).Vase life increased under the effect of treatment with calcium nanoparticles and silver nanoparticles (10 mg.L-1) and caused an increase of 4 days compared to the control (0 mg.L-1) The treatments decreased the amount of malondialdehyde and also increased the relative amount of absorbed solution, total protein and superoxide dismutase enzyme. Based on the results of this study, calcium and silver nanoparticles improved qualitative traits. The simultaneous treatment of calcium and silver nanoparticles (concentration 10 mg.L-1) compared to the control (0 mg.L-1) caused an increase (14%) in flower diameter, fresh weight (12%), vase solution uptake (46%), superoxide dismutase (21%) and malondialdehyde reduction (37%). Two other important findings emerged from this work: (1) The nanoparticles used in this experiment caused the activation of the enzyme antioxidant system in the treatments (2) The simultaneous treatment of nanoparticles calcium before harvesting and silver nanoparticles treatment after harvesting by activating the antioxidant enzyme system and maintaining the ability to absorb the solution increased the vase life of rose cut flowers. In general, the treatment with calcium nanoparticles at a concentration of 10 mg. L-1 before harvesting and the treatment with silver nanoparticles at a concentration of 10 mg.L-1 after harvesting were the most effective treatments in most traits.
Conclusion
Calcium is one of the most effective factors in increasing the vase life of rose cut flowers. Treatments containing calcium increase absorption of vase solution uptake. The treatment of calcium nanoparticles increases the total protein and superoxide enzyme compared to the control, so that the simultaneous use of silver and calcium nanoparticles increases the vase life of rose-cut flowers compared to the control. Calcium probably activated a chain of reactions by activating the message transmission system and caused the expression of genes involved in the antioxidant system of the samples. silver nanoparticles by affecting the absorption of vase solution uptake and reducing the amount of malondialdehyde and increasing the total protein and superoxide dismutase enzyme compared to the control, increase the vase life of cut flowers. According to the results obtained from the present research, it can be concluded that use of calcium nanoparticles with silver nanoparticles had great effects on most of traits in compared to control treatment. The use of calcium nanoparticles with silver nanoparticles improves the vase life conditions by increasing water uptake and consequently increasing the relative fresh weight.
Postharvest physiology
M. Kiaeshkevarian; T. Raiesi; B. Moradi; J. Fattahi Moghadam; M. Faghih Nasiri
Abstract
Introduction
Consumers demand for organic products is increasing due to their awareness of health and nutritional quality. Organic manures maintain soil health and ecological balance of the region. Organic agriculture, as an alternative agricultural system to protect human health and the environment ...
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Introduction
Consumers demand for organic products is increasing due to their awareness of health and nutritional quality. Organic manures maintain soil health and ecological balance of the region. Organic agriculture, as an alternative agricultural system to protect human health and the environment can improve the quality and storability of the product. Kiwifruit is one of the most important agricultural products in north of Iran, which plays an effective role in trade and employment of the people. Fertilization is one of the main factors affecting the yield and quality of kiwifruit. Growers use organic manures and chemical fertilizers in their orchard to achieve higher yields. It is necessary to study the effect of various organic manures available in the region on the nutrition of kiwifruit vines due to increase chemical fertilizer prices and the formation of the market for organic fruits. Therefore, the aim of this study was to compare the effect of using five types of organic manures and chemical fertilizer on the quality of Hayward kiwi fruit during cold storage.
Materials and Methods
This research was conducted as randomized complete block design consisting six treatments (including complete chemical fertilizer, sheep manure, cow manure, chicken manure, vermicompost and azolla) on Hayward kiwifruit vines in orchard and factorial experiment with three replicates in cold storage during four years. The fruits were harvested at TSS: 6.5 (approximately mid-November) and then stored at 0.5 ° C and 90% RH for three months. Sampling was performed every month and physicochemical characteristics, including flesh color parameters (L*, C*, h◦), total soluble solids, titratable acidity, firmness and weight loss of fruit were measured. Sensory evaluation of fruits was also performed at the end of three months cold storage. Analysis of variance of the data was done using SAS 9.1 software. The significance of differences between the mean of treatments was determined by using Duncan’s test.
Results and Discussion
The results showed the interaction between year, type of nutrition and cold storage period affected color indices, lightness and chroma. Lightness and chroma value didn’t show significant differences between organic and chemical fertilizer treatments. In addition, their value decreased during cold storage period, significantly. The chroma value indicates the degree of saturation of the green color and is associated with fruit firmness. The hue value was also influenced by the interaction between year and cold storage period and the simple effect of the nutrition type. The highest hue value was observed in chicken manure (108.63) and the lowest in vermicompost (107.66). The hue value decreased significantly after 90 days cold storage. According to the results, a decrease in fruit firmness, TA and an increase in TSS and TSS/TA were observed during cold storage irrespective of treatments. After 90 days, total soluble solids content was higher when organic fertilizers were applied. During the storage of kiwifruit, total soluble solids content increased, significantly. The titratable acidity value in organic fertilizer treatments was higher than chemical fertilizer after 90 days cold storage, significantly. Moreover, titratable acidity value decreased at the end of the cold storage period, significantly. The highest flesh fruit firmness was obtained in cow manure (8.74 kg/cm2) in forth year and chemical fertilizer treatment had the lowest flesh firmness (3.2 kg/cm2) in third year. Fruit lost firmness gradually during the cold storage period. However, no significant difference was found in maturity index (TSS/TA) between treatments. The TSS:TA ratio is highly increased after 90 days. Based on the results of the last two years, azolla, cow and chicken manures showed less weight loss percentage than chemical fertilizer treatment. Moreover, weight loss increased significantly during cold storage period in all treatments and years. Also the results of sensory analysis showed that fruits treated with vermicompost had a higher overall acceptance than other treatments.
Conclusion
Generally, organic nutrition plays an important role in increasing the nutritional value and shelf life of kiwifruit cv.Hayward. Organically produced fruits had higher firmness than conventionally grown fruits during storage. Application of cow manure and vermicompost showed favorable effects on important properties of kiwi fruit such as firmness, weight loss, TSS, TA and sensory quality. Therefore, organic fruits will have better quality in the cold storage. As a result, it seems that by reducing the use of chemical fertilizers in the current orchards, kiwi production will be close to the standards defined for organic fruit.
Postharvest physiology
M.R. Zandi; A.H. Aboutalebi Jahromi; B. Behroznam; A. Zakerin
Abstract
Introduction
Strawberry is one of the most important small fruits in the world, which is cultivated as a perennial plant in temperate regions of the world. Ripe strawberry fruit contains compounds such as protein, fiber, sugars such as fructose, glucose, sucrose, organic acids, vitamins, minerals, ...
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Introduction
Strawberry is one of the most important small fruits in the world, which is cultivated as a perennial plant in temperate regions of the world. Ripe strawberry fruit contains compounds such as protein, fiber, sugars such as fructose, glucose, sucrose, organic acids, vitamins, minerals, as well as phenolic compounds and anthocyanins. The aim of this study was to investigate some hormonal treatments and magnetic field on some physiological and biochemical characteristics, shelf life and postharvest life of strawberry cv. Selva under temperature stress.
Materials and Methods
This experiment was performed as a split plot based on a completely randomized design with 3 replications. Physiological and biochemical characteristics were studied on several tissues of Selva strawberry cultivar under several different temperature treatments. The treatments were gibberellic acid at three levels of control, 50 and 100mg/l in the main plots, magnetic field at 3 levels of control, 10 and 20ms, in the subplots and temperature stress in three levels including 2, 8 and 20°C. It was done on strawberries in subplots. Healthy prepared strawberry fruits were subjected to magnetic treatments and then immersed in hormonal solutions for 2min and after drying, stored for 8 days in different refrigerators at temperatures according to research treatments. The samples were then removed from the refrigerator and transferred to a laboratory to measure various characteristics. The studied traits included: fruit weight, fruit diameter, fruit length, fruit moisture content, titratable acidity, fruit juice pH and vitamin C.
Results and Discussion
Results of analysis of variance showed that the simple and triple interactions of treatments on all studied traits were significant. Comparison of the mean triple interaction of gibberellic acid treatment × magnetic field × temperature showed that the highest amount of fruit weight (19.49g), the highest amount of fruit diameter (33.7mm), the highest fruit length (48.62mm), the highest fruit moisture (34.65%) was obtained in the treatment of 50mg/l gibberellic acid, ten Tesla magnetic field and a temperature of eight degrees Celsius. The lowest fruit weight of 10.65 g was obtained in the treatment of non-use of gibberellic acid, non-use of magnetic field and temperature of 20°C. The lowest fruit weight loss of 3.74% was obtained in the treatment of 50 mg/l gibberellic acid, 20 Tesla magnetic field and 2°C. The lowest fruit diameter of 21.52mm was obtained in the treatment of non-consumption of gibberellic acid, absence of magnetic field and temperature of 20°C. The lowest fruit length of 25.63 mm was obtained in the treatment of no gibberellic acid, no magnetic field and a temperature of 20°C. The lowest amount of titratable acidity (0.31%), the lowest pH of fruit juice (4.68) and the highest amount of vitamin C (34.92mg/100 ml) in the treatment of non-use of gibberellic acid, no use of field Magnetic and a temperature of 20°C were obtained. The lowest amount of vitamin C was equal to 20.5mg/100ml in the treatment of no use of gibberellic acid, no use of magnetic field and a temperature of 20°C.High concentrations of gibberellic acid have a beneficial effect on increasing cell division and fruit size. Gibberellic acid increases fruit size and weight due to its effect on increasing cell division in the early stages of fruit development and increasing cell size at late fruit ripening. Magnetic field also affects plant metabolic activity. Fruit volume includes fruit length. It decreases due to the magnetic field. Fruit weight showed a significant positive correlation with fruit diameter, fruit length, fruit moisture and vitamin C. In terms of the triple interaction of the research treatments, the best effective treatment for increasing the storage time of strawberries was the combined treatment of 50 mg/l gibberellic acid and ten Tesla magnetic field and a temperature of 8°C.
Conclusion
Fruit weight showed a significant positive correlation with fruit diameter, fruit height, fruit moisture and vitamin C. In terms of the triple interaction of the research treatments, the best effective treatment for increasing the storage time of strawberries was the combined treatment of 50 mg/l gibberellic acid and ten Tesla magnetic field at a temperature of 8°C.
Postharvest physiology
M. Cheraghi; A.A. Hatamnia; F. Ghanbari
Abstract
Introduction
Salinity is the most important environmental parameter limiting plant growth and productivity. The detrimental effects of high salinity on plants can be observed at the whole-plant level as the death of plants and/or decreases in productivity. Increasing salinity ...
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Introduction
Salinity is the most important environmental parameter limiting plant growth and productivity. The detrimental effects of high salinity on plants can be observed at the whole-plant level as the death of plants and/or decreases in productivity. Increasing salinity is accompanied by significant reductions in number of leaves per plant, shoot weight, root weight, shoot length, and root length. With an increase in salinity, water potential and osmotic potential of plants become more negative. Two medicinal species of Coriandrum sativum L. and Anethum graveolens L. are herbaceous and annual plants of the Apiaceae family, which have many uses in the pharmaceutical and food industries. Considering the importance of these two medicinal species and the increase of environmental stresses including salinity stress in recent years, this research aims to investigate the effect of external application of melatonin on resistance to salinity stress in Coriandrum sativum L. and Anethum graveolens L. species and its effect on some morphological and physiological characteristics of these two species under salt stress.
Materials and Methods
This research was conducted in a factorial experimental format based on a randomized complete block design with three replications. Experimental treatments include five levels of salinity (0, 40, 80, 120 and 160 mM) and two levels of melatonin foliar spraying (0 and 100 μM). After the end of the treatment period, the morphological and physiological characteristics of the plant were measured by the different methods. Data analyses were performed using SPSS software version 20. Results were analyzed using one-way analysis of variance (ANOVA) followed by Tukey’s multiple comparison test. The results were expressed as mean values and standard error (SE) of the means.
Results and Discussion
The results of variance analysis indicated that species, melatonin and salinity stress have a significant effect on all morphological factors at the p < 0.05. The results of compare means showed that the number of leaves in both plants has a significant decrease at the probability level of 5% with the increase in salinity. However, the amount of this decrease in the samples that have been affected by melatonin is lower than the samples without melatonin. The use of melatonin has reduced the negative effects of salinity stress in two plants, so that at the salinity level of 160 mM sodium chloride, the use of melatonin has increased the fresh and dry weight of coriandrum sativum L. shoots by 7 and 3.61 times, respectively. The results of variance analysis showed that melatonin and salinity stress have a significant effect on all pigments. The results shown that with the increase in the level of salinity stress, a significant decrease (p < 0.05) was observed in the amount of chlorophyll and anthocyanin pigments of two species. The results of variance analysis showed that species and melatonin have a significant effect at the p < 0.01 on all physiological parameters, and salt stress has a significant effect at the p < 0.01 on all the physiological parameters except of relative water content. Also, the interaction effects of species with salinity, species with melatonin, melatonin with salinity and the interaction of all three factors have a significant effect at the 1% probability level on the parameters of proline and total phenol.With the increase in salinity, the amount of total protein in both species decreased, but the amount of this decrease was lower in the plants that were treated with melatonin. In coriandrum sativum L. plant, the amount of total protein reduction at 160 mM salinity level is 42.31% compared to the control, but this reduction was 28.9% in the plants that were treated with melatonin. Also, in the Anethum graveolens L., the amount of total protein reduction at the salinity level of 160 mM was 29.78% and 21.06% respectively, in the samples without melatonin treatment and under melatonin treatment.
Conclusions
The results of variance analysis of the data showed that melatonin has a significant effect at the probability level of 1 and 5% on all morphological and physiological parameters measured in both plants. Also, the compare means showed that with the increase in the level of salinity stress, a significant decrease in the probability level of 5% was observed in the parameters measured in two plants. In general, the external application of melatonin moderates the negative effects of salinity stress, and therefore melatonin can be used to improve the growth of plants under stress.
Postharvest physiology
A. Sharafshah Rostami; B. Kaviani
Abstract
Introduction
Carnation (Dianthus caryphyllus L.), from Caryophyllaceae family, is one of the most important cut flowers in the world that its short vase life reduces the economic value. Postharvest longevity of cut flowers can be prolonged using carbohydrates (sugars) in a vase jar. Cut flowers ...
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Introduction
Carnation (Dianthus caryphyllus L.), from Caryophyllaceae family, is one of the most important cut flowers in the world that its short vase life reduces the economic value. Postharvest longevity of cut flowers can be prolonged using carbohydrates (sugars) in a vase jar. Cut flowers undergo some physiological and biochemical changes that often lead to an early senescence. To delay the aging process in cut flowers, it is necessary to evaluate many aspects of preparation for storage conditions, especially preservative solutions that affect the quality and longevity of these flowers. Many flowers are harvested before they are fully developed, to ensure a long postharvest life and to minimize mechanical damages that might occur during handling. The growth and development of flower buds on cut flowers require food (especially carbohydrates), which is stored in the leaves and stems. These stored carbohydrates can be mobilized for the flower bud to use but maybe they are insufficient when the buds are harvested at a tight-bud stage. To maintain metabolic activities, including respiration, even for cut flowers that have reached full development, it is necessary to provide adequate reserves to achieve acceptable postharvest life. When stored materials are low, leaves and flowers age faster and the petals fade. Under these conditions, supplements can be provided to the flowers by adding sugars such as glucose, fructose and sucrose to the vase solutions. However, it is important to note that a sugar solution is also suitable for the growth of microorganisms, so that an antimicrobial agent should be added to the vase solution as well. Many researches were carried out on prolonging the vase life of cut carnation flowers with different preservative solutions together with an antimicrobial agent. Studies on postharvest longevity of cut carnation flowers using sugars as preservative solutions is low. Therefore, the aim of the present study was to evaluate the effect of sugars (glucose, fructose and sucrose) and application time on vase life and some physiological parameters of carnation cv. ‘Yellow Candy’ cut flowers.
Materials and Methods
A factorial experiment based on completely randomized design in three replicates was performed in order to investigate the effect of different levels (0, 50 and 100 g/L) of three types of sugars (glucose, fructose, and sucrose) and two sugar application times (the first and second 24 h, on 2019) on vase life of carnation cv. ‘Yellow Candy’ cut flowers. Some other traits such as water uptake, dry mater, relative fresh weight, protein and carotenoid of petal, leaf chlorophyll, POD and SOD enzymes activity and MDA were also measured. The statistical analysis of data was performed using Statistical Package for Social Sciences (SPSS) v 16.0. Least significant difference (LSD) test at P < 0.05 was used to find out the significance of differences among the mean values.
Results and Discussion
Results showed that the effect of different levels of sugars on all evaluated traits was significant. Each three levels of sugars at each two applied times caused to increase vase life and relative traits. Maximum vase life (18 days) was obtained in 50 g/L glucose at the first 24 h with no statistically significant differences with the 100 g/L sucrose and fructose at the first 24 h. The highest water uptakes and dry matter, the lowest POD and SOD activity and minimum MDA were obtained in treatment of 50 g/L glucose at the first 24 h. The study found that the highest levels of petal protein content, chlorophyll a, b, and total chlorophyll were achieved in carnation "Yellow Candy" cut flowers treated with 50 g/L glucose after 24 hours of harvesting. The application of sugars at the first 24 hours after harvesting had a greater impact on improving the vase life of the flowers compared to the second 24 hours. Therefore, the use of glucose as an external holding solution, preferably within the early hours of harvesting, is recommended to prolong the postharvest life of carnation "Yellow Candy" cut flowers. The study also revealed that the use of external holding solutions, particularly sugars combined with antimicrobial agents, can have a positive effect on prolonging the vase life of cut flowers. The concentration of sugar required in the holding solution varies depending on the type of flower being treated, with most flowers requiring a concentration of 2% sugar. However, some flowers may require higher concentrations, up to 4-6%, while others may be damaged if treated with concentrations higher than 1%. The application of sucrose has been shown to increase glucose and fructose levels in petals, further supporting the use of external holding solutions containing sugars for extending the vase life of cut flowers. Therefore, it is important to examine each flower before treating it to determine the optimal concentration of sugars. Sugars are a source of energy and carbon for cut flowers and play an important role in decreasing the protein degradation and ethylene production, maintenance of osmotic balance, increasing water uptake, and finally delaying in senescence process
Postharvest physiology
M.J. Karami; M. Rahemi; M. Yassaie; A. Karami
Abstract
Introduction
Raisins are dried grapes and are prepared from some varieties of grapes (Vitis vinifera) in different ways, such as exposing grapes to direct sunlight and mechanical methods. There is a possibility of contamination of various types of raisins with different microorganisms during the ...
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Introduction
Raisins are dried grapes and are prepared from some varieties of grapes (Vitis vinifera) in different ways, such as exposing grapes to direct sunlight and mechanical methods. There is a possibility of contamination of various types of raisins with different microorganisms during the stages of harvesting and drying grapes, transportation and marketing of raisins, especially when they are presented in open boxes. The traditional process of preparing and packing raisins in Bovanat region (the main raisin production area of Fars province) makes this product prone to microbial contamination dangerous for human health. The history of consumption of raisin is very old. The Bible provides the first written mention of raisin around 1000 B.C., drying is one of the oldest methods of food preservations; the main purpose of this experiment is reducing the moisture content to level which allows safe storage without spoilage. It has been reported that the use of hydrogen peroxide (H2O2) treatments reduces the microbial contamination loads in dried raisins. Moreover, washing with hydrogen peroxide solution can markedly reduce the loads of human pathogens including Escherichia coli. Primitive methods of making and packaging of raisins in Bavanat region contribute to make them vulnerable to microbial contamination and may be harmful for health. This research was conducted in order to determine the initial microbial contamination on the surface of three types of raisins prepared from the Keshmeshi grape cultivar and using hydrogen peroxide to reduce these microbial contaminations.
Materials and Methods
The use of hydrogen peroxide as a potential antimicrobial treatment was investigated for three types of raisins in Bovanat region. For this purpose, three samples of raisins (Sun-dried, Shade-dried and Sultana raisins) have investigated. Raisins samples randomly were purchased from a local retailer in Shiraz (Iran). For this experiment, raisin samples with uniform size were selected and damaged or diseased berries were discarded. Two concentrations of hydrogen peroxide applied to microbial disinfection were 0% and 0.9%. The raisins that were prepared underwent a treatment process where they were dipped for 5 minutes in solutions containing either 0% or 0.9% hydrogen peroxide. Afterward, the raisins were washed with distilled water for 1 minute to remove any residue. A control group was also included, consisting of raisin samples treated with water (0% hydrogen peroxide). For each sample, measurements were taken for microbial count, population of yeasts and other molds, Aspergillus, Coliform bacteria, and Escherichia coli. The experiment was designed as a factorial (2x3) based on a completely randomized block design with 3 replications. The data were analyzed using SPSS 22.0, and mean data were compared using Duncan's multiple range tests at a 1% probability level.
Results and Discussion
The results showed that there was a significant difference (P≤1%) between hydrogen peroxide concentration treatments regarding to microbial contamination. There was also a significant difference (P≤1%) between the raisin samples in terms of microbial contamination. The results also revealed the presence of high amount of microbial infection on surface of all raisin samples. The microbial contamination load of Sultana raisins was higher than other raisins. The results also indicate that Escherichia coli was not detected in both sun-dried and shade-dried samples, but it was observed in Sultana raisins. Surface disinfection of Sultana raisin samples with 9% of hydrogen peroxide removed Escherichia coli infection. Hydrogen peroxide was effective in reducing the microbial contamination of all three raisin samples. It seems hydrogen peroxide to be more effective in reducing microbial contamination in sun-dried and shade-dried samples. Sultana raisin had highest contamination of mold and yeast while sun-dried and shade-dried raisins were lowest. The effect of hydrogen peroxide on reducing mold and yeast contamination was not the same in all raisin samples, so that the highest effect on reducing mold and yeast contamination was found in sun-dried and shade-dried raisins. The least effect on this contamination was observed in sultana raisins. Aspergillus was not detected in sun-dried and shade-dried samples but it was observed in sultana raisins. Hydrogen peroxide was not effective against Aspergillus. The microbial contamination of all raisin samples which affected by 0.9% hydrogen peroxide was decreased significantly (P≤1%). Effect of hydrogen peroxide at 0.9% on removing of microbial infection in sun-dried and shade- dried raisins was similar and it was more than Sultana raisins.
Conclusion
All three raisin samples were infected with Coliform bacteria, mold and yeast. In the case of Escherichia coli infection, it was detected only in sultana samples. Hydrogen peroxide was effective in reducing the microbial infection of all raisin samples. It was more effective in reducing the total number of microbes in sun-dried and shade-dried raisins. Hydrogen peroxide with a concentration of 0.9% is effective for eliminating the microbial infection of raisins, and the use of hydrogen peroxide with a concentration of 0.9% can be used to disinfect raisins.
Postharvest physiology
Chnoor Hosseini; M.R. Asghari; M. Khezri
Abstract
Introduction Cherry (Prunus avium L.) is one of the most important fruit products and due to its polyphenol and antioxidant compounds, it contributes to the nutrition and health of millions of people. Due to its high perishability, this fruit suffers from post-harvest physiological losses. According ...
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Introduction Cherry (Prunus avium L.) is one of the most important fruit products and due to its polyphenol and antioxidant compounds, it contributes to the nutrition and health of millions of people. Due to its high perishability, this fruit suffers from post-harvest physiological losses. According to the proven antifungal activity of plant essential oils, their use as a natural substance to reduce post-harvest waste, increase shelf life and ensure the health of consumers of horticultural products.Material and Methods In the present study, the effect of marjoram essential oil in different concentrations (0, 250, 500, 750 and 1000 µl/l) on biochemical reactions of Mashhad cherry fruit var takdaneh, including phenylalanine ammonialyase enzyme activity, total anthocyanin content, ascorbic acid content, tissue color, polyphenol oxidase enzyme activity, fruit rot and browning of the tail were evaluated with three replications. The treated fruits were transferred to the refrigerator for 30 days at a temperature of 1.0 °C and a relative humidity of 90-95%. Qualitative measurements of fruits were performed during three periods before storage, on the 15th day and on the 30th day of storage. Analysis of variance (ANOVA) was performed based on factorial experiment in a completely randomized design. Mean comparison was performed based on Duncan's multiple range test using SAS software and its graphs were drawn with Excel. Finally, correlation analysis was performed using R software.Results and Discussion The results of this evaluation showed that marjoram essential oil maintained the activity of phenylalanine ammonialyase enzyme, total anthocyanin content, ascorbic acid content and color significantly. It also reduced the activity of polyphenol oxidase activity, tissue color change, rot and browning of cherry fruit tail. The level of ascorbic acid in all treated samples decreased over time, but this decrease was more severe in the control sample than the other treatments. Increasing storage time and essential oil concentration improved the amount of anthocyanin in the treated fruits. The essential oil at a concentration of 750 μl/l avoided reduction of color change compared to the control. The activity of phenylalanine ammonialyase enzyme in all essential oil concentrations in both periods had an upward trend. The lowest and highest polyphenol oxidase enzyme activity were recorded in 750 μl/l essential oil treatment and control treatment, respectively. use of essential oil decreased the browning of the fruit tail in which, is probably due to the antioxidant activity of the essential oil. Also, the lowest rate of decay and the highest marketability were observed in the concentration of 750 μl/l of marjoram essential oil. On the other hand, there were significant correlations between most traits. Marketability as one of the most important traits had a positive correlation with traits such as ascorbic acid (r=0.82**) and fruit color (r=0.77**). These results clearly show that the increase of these traits leads to high marketability of cherry fruit. Also, the existence of a negative correlation between the rate of maintaining marketability with the traits of rot (r= -0.95**) and browning of the fruit tail (r= -0.89**) shows that with the increase of these traits, the marketability of the fruit decreases. Finally, according to the findings of the present study and considering the quality and durability of treated cherry fruits compared to untreated fruits, instead of harmful chemical compounds, marjoram essential oil can be recommended as an additive in cherry fruit.Conclusion The use of plant essential oils as a natural method can be effective in increasing the shelf life of this fruit by preventing deterioration and degradation. The results of this study showed that marjoram essential oil at a concentration of 750 µl/l by increasing and maintaining ascorbic acid, anthocyanin, PAL enzyme activity, marketability and also by reducing the activity of PPO enzyme, color variability, degree of rot and browning of the fruit tail led to maintaining the internal quality and better durability of the cherry fruit during storage. The reason for this can be related to the phenolic and antioxidant compounds in marjoram essential oil. These compounds directly affect fruit spoilage and indirectly increase the host fruit's defense system and maintain fruit quality. According to the results of this study, marjoram essential oil with a concentration of 750 µl/l can be introduced as a healthy method to maintain physicochemical properties and improve the cherries quality characteristics after harvest.
Postharvest physiology
Nilofar Haresabadi; S.A. Hosseini; M.H. Aminifard
Abstract
Introduction
Tomato, scientifically known as Solanum lycopersicum L., belongs to the Solanaceae family and is susceptible to various diseases, resulting in reduced yield. Among the diseases, the Tomato spotted wilt virus (TSWV), which belongs to the Tospovirus genus and Bunyaviridae family, causes ...
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Introduction
Tomato, scientifically known as Solanum lycopersicum L., belongs to the Solanaceae family and is susceptible to various diseases, resulting in reduced yield. Among the diseases, the Tomato spotted wilt virus (TSWV), which belongs to the Tospovirus genus and Bunyaviridae family, causes significant damage to tomato crops and other greenhouse plants. Therefore, it is crucial to find ways to increase plant resistance and control viral infections. One effective method is through proper plant nutrition, which can enhance plant resistance by balancing fertilizer consumption and nutrient supply. Iron (Fe) is an essential element for plants and plays a significant role in increasing their tolerance to various stresses. In Order to evaluate the interaction effects of Tomato spotted wilt virus and Fe on some biochemical traits of Mobil and RioGrand tomato cultivars, a study was conducted in Birjand Faculty of Agriculture.
Materials and Methods
Experiment in a Random complete design with greenhouse conditions, with 3 replications and 4 treatments Done. Experimental factors include cultivar with two levels (Mobil cultivar and Rio Grand cultivar) and Fe foliar application in the presence of virus with these three (zero, 1.5 and three milliliter of Fe fertilizer per liter of water). First, two varieties of RioGrand and Mobil tomato seeds were prepared and planted in seedlings. Then, in the two-leaf stage, they were transferred to pots filled with sterile soil and kept in greenhouse conditions. After seedling establishment, the first foliar application of Fe fertilizer was done and in the five to seven leaf stage, the virus was inoculated on all leaves. Then, the second stage of fertilizer was applied 10 days after the first fertilizer and finally, after the last stage of foliar application, the samples were transferred to the laboratory. In Order to accurately investigate the effect of Fe on important plant factors, extracts were taken from the samples. Then, the amount of antioxidants, carbohydrates, Flavonoids, Chlorophyll (a, b and total chlorophyll) and phenol was measured. Finally, the final data analysis was performed using SAS statistical software.
Results
The results showed that the simple effect of cultivar on the amount of phenol and flavonoids was significant at the level of one percent and the highest amount of phenol was recorded in Mobil cultivar and the highest amount of flavonoids was recorded in RioGrand cultivar. The effect of treatments on chlorophyll a, total chlorophyll index and antioxidant enzymes was significant at the level of 1% probability and carbohydrate content at the level of 5% probability. The results showed that feeding Fe at a concentration of 1.5 milliliter had a favorable effect on carbohydrate content and increased its amount in infected plants compared to control plants. This Increase effect may be useful for improving tolerance in a variety of tomatoes. According to the results, an increase in foliar application concentration to 3 milliliters led to a decrease in carbohydrate levels. Mechanical inoculation with a positive sample of the virus resulted in plant contamination. However, virus infection increased carbohydrate and antioxidant enzyme levels in tomatoes. The effect of cultivar on treatment was only significant in the amount of antioxidant enzymes at a one percent probability level, with the Mobil cultivar showing the highest response to virus infection treatment. Therefore, it can be concluded that a concentration of 1.5 milliliters of Fe fertilizer could be effective in increasing carbohydrate levels, as well as utilizing enzymatic and non-enzymatic antioxidant components to prevent viral penetration to some extent and reduce symptoms, particularly in the Mobile cultivar. However, the RioGrand cultivar produced less antioxidant components. Different cultivars of the same plant species have been reported to have varying responses to different types of infections, such as viruses, fungi, and bacteria. These differences are attributed to genetic variations among cultivars, which leads to different resistance mechanisms.
Conclusion
The final results showed that in the early stages of greenhouse tomato growth, Fe nutrition had an effect on the biochemical properties of the plant and had a positive effect on some traits. In total, Fe fertilizer with a concentration of 1.5 milliliter increased carbohydrates in plants infected with Tomato spotted wilt virus and together with phenol and antioxidants affected the spread of the virus, especially in Mobil cultivar.
Postharvest physiology
Simin Garavand; S.F. Mousavi; S.H. Hekmatara
Abstract
Introduction
Gerbera is one of the most important cut flowers that has a short vase life. Like other cut flowers, one of the main concerns after harvesting this flower is reducing its quality. The application of carbon nanotubes as preservative solutions increase water uptake, balances water relations, ...
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Introduction
Gerbera is one of the most important cut flowers that has a short vase life. Like other cut flowers, one of the main concerns after harvesting this flower is reducing its quality. The application of carbon nanotubes as preservative solutions increase water uptake, balances water relations, and increases the vase life of cut flowers. Agglomeration, lack of proper dispersion, and severe hydrophobicity are the disadvantages of carbon nanotubes that prevent optimal dispersion in the solution. In this study, polymers (polyvinyl pyrrolidone (PVP), polyethylene glycol (PEG), and non-ionic surfactant Triton X-100) were used to increase the dispersion of multiwalled carbon nanotubes (MWCNTs). Their effect on the longevity of cut gerbera flowers was also investigated.
Materials and Methods
The experiment was performed as a factorial experiment in a completely randomized design with four replications. Gerbera (Gerbera jamesonii cv. Rosalin) flowers with fully opened ray florets were purchased. During transportation, each cut flower was covered individually with a cellophane sheet and was placed inside a box of paper to minimize water loss. Gerbera stems were placed in a vase solution as pulse treatment for 24h. Treatments included various concentrations of nanocomposite including control (distilled water), MWCNTs-PVP nanocomposite (1 and 2 mg L-1), MWCNTs-PEG nanocomposite (1 and 2 mg L-1), and MWCNTs-Triton X-100 nanocomposite (1 and 2 mg L-1). Distilled water was used for the control treatment. After the cut gerbera flowers underwent pulse treatment, they were placed individually into glass vases filled with distilled water. Throughout the experiment, the vase life, relative fresh weight, water uptake, relative water content of petals and stems, as well as the bacterial population at the end of the stem were measured.
Results and Discussion
The study showed that the MWCNTs-Triton X-100 with a concentration of 2 mg L-1 provided the longest vase life of cut flowers, with a duration of 22.5 days, which was an 8-day increase compared to the control. The other nanocomposites (MWCNTs-PVP and MWCNTs-PEG) also improved the longevity of the cut flowers compared to the control. The nanocomposites in the vase solution affected the relative fresh weight and water uptake of the cut stems. The study found that the water uptake pattern was similar to the fresh weight of the flower, and the water uptake capacity of the stem gradually decreased with time. The MWCNTs-Triton X-100 with a concentration of 1 mg L-1 resulted in the highest amount of water uptake. Cut flowers pulsed with this concentration exhibited the highest relative water content in both petals and stems. The application of MWCNTs-PEG nanocomposite (1 mg L-1) in vase solution increased the relative fresh weight of gerbera cut flowers. Our findings suggest that MWCNTs can increase water uptake, resulting in increased fresh weight in the cut stem. SEM analysis revealed that after the evaluation period, MWCNTs were detected in the stem of cut gerbera and deposited on the stem's internal surface. Our finding showed that the bacterial population at the end of the stem in control treatment during the vase life period was higher than the bacterial population at the end of the stem of flowers treated with MWCNTs-Triton X-100 treatment (2 mg L-1). Therefore, reducing bacterial blockages in the xylem vessels improves the water uptake and vase life of cut flowers.
Conclusion
When gerbera cut flowers are harvested and kept in vase solutions, they face some challenges including wounding and water stress. Continuity of water flow in cut flower stem after cutting is an important factor in determining postharvest quality and longevity of cut flowers. Applying a solution containing well-dispersed MWCNTs is a novel approach for facilitating the entry of this nanotube into plants. The use of a composite of MWCNTs with X-100, PVP, and PEG exhibits excellent dispersion properties in the aqueous media of vase solution. These nanocomposites were successful compounds in increasing water uptake, maintaining fresh weight, and increasing the vase life of gerbera cut flowers. The findings of the present study showed that nanocomposites inhibit bacterial growth. These results suggest that the elimination of barriers to water flow in the cut stem helps to keep the longevity and delayed senescence.
Postharvest physiology
M. Shahabi; S. Rastegar
Abstract
Introduction Narcissus (Narcissus tazetta) has high demand in flora markets due to its beauty, having a multi-floret flowerhead and delicate fragrance. The appearance quality and vase life of cut flowers decreased after harvest due to flower senescence, loss of petals turgor, reduced water absorption, ...
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Introduction Narcissus (Narcissus tazetta) has high demand in flora markets due to its beauty, having a multi-floret flowerhead and delicate fragrance. The appearance quality and vase life of cut flowers decreased after harvest due to flower senescence, loss of petals turgor, reduced water absorption, transpiration, fresh weight loss, and reduced water potential which reduces the economic and ornamental value of flowers at the consumer. One of the important reasons for the poor postharvest quality of Narcissus tazetta is the loss of turgor and their high sensitivity to browning of the petals. Browning mechanisms are chemically divided into enzymatic and non-enzymatic browning reactions. Enzymatic browning, which causes important reactions and discoloration, is one of the important factors affecting the quality and shelf life of fresh produce. Previous studies have shown that the activity of polyphenol oxidase (PPO) and peroxidase (POD) is positively correlated with browning during the postharvest storage of fruits and vegetables. Nitric oxide (NO) is recognized as a biological messenger in plants. It is a highly reactive gaseous free radical. Optimum NO levels could delay the climacteric phase of many tropical fruits and prolong the post-harvest shelf life of a wide range of horticultural crops by preventing ripening and senescence. Nitric oxide also could prevent the activity of PPO, phenylalanine ammonialyase (PAL) and POD, and keep the highest activity of superoxide dismutase (SOD).Materials and MethodsNarcissus (Narcissus tazetta L. cv. Shahla e-Shiraz) cut flowers at their commercial maturity stage (Goose-neck) were harvested from a production field in Farse province and. then they were transported to the laboratory. Healthy and uniform cut flowers with the same number of buds, a similar size and growth status were selected. Cut flowers were subjected to pulsed treatment of sodium nitroprusside for 24 hours on two levels (25 and 50 μM) and then kept in containers. Samples were stored at 20 ± 2 °C, relative humidity of 70-60%, with light cycle of 12 hours light and 12 hours dark. In this experiment, various physiological and biochemical indices including apparent quality (wilting index), cell membrane stability index (%), petal relative water content (%), color index and browning using a colorimeter, relative weight using digital scale (g), flower diameter, PPO and POD were examined. Results and DiscussionSodium nitroprusside treatment reduced the browning process by reducing the activity of POD and PPO enzymes. The effect of sodium nitroprusside was concentration-dependent. Sodium nitroprusside maintains membrane stability by protecting the membrane and preventing lipoxygenase activity and scavenging free radicals that have attacked the membrane. Sodium nitroprusside-maintained flower diameter due to its role in eliminating free radicals, delaying the aging process and maintaining flower quality. Discoloration and browning reactions of cut flowers reduce their appearance quality, leading to economic loss. The browning of the petals due to senescence is one of the important factors limiting the vase life of narcissus. It has been shown that PPO and POD are the key enzymes for the oxidation of the phenolic substrate (especially simple phenols) and the production of the brown compounds. It has also been suggested that the stability index of the cell membrane, which represents the ion leakage of the tissues, is diminished extremely as the longevity is increased. Another effective factor in determining the quality and vase life of cut flowers is the water-holding ability and water balance of the cut flowers petals. Changes in the cut flower fresh weight could also be regarded as one of the most important postharvest physiological disorders that affected the quality, vase life and commercial value of the cut flowers. Fresh weight loss, which is one of the most important reasons for the wilting of the flowers, is due to the less water uptake and more respiration rate.Conclusion Sodium nitroprusside treatment maintained the quality of Narcissus tazetta L. cv. Shahla e-Shiraz by increasing the relative water content of the petals and maintaining the cell stability index, as well as reducing the activity of browning enzymes (PPO and POD).Of course, the concentration used was very important.The best results were observed at lower concentrations (25 μM) of sodium nitroprusside.
Postharvest physiology
M. Ghafouri; F. Razavi; M. Arghavani; E. Abedi Gheslaghi
Abstract
Introduction Nowadays, the application of chemical compounds is limited due to their harmful effects on human and the environment health. The benefits of seaweeds as sources of organic matter and fertilizer nutrients have been known to agriculture for centuries, especially in coastal areas extracts ...
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Introduction Nowadays, the application of chemical compounds is limited due to their harmful effects on human and the environment health. The benefits of seaweeds as sources of organic matter and fertilizer nutrients have been known to agriculture for centuries, especially in coastal areas extracts of these seaweeds have been used for decades as foliar- and soil-applied treatments in crop production systems due to the presence of a number of plant growth-stimulating compounds. Unlike chemical fertilizers, extracts derived from seaweeds are biodegradable, non-toxic and non-hazardous to humans, animals and birds. Therefore, it is required to find a safe compound that is utilized in the postharvest technology of fruit and vegetables. Pre-harvest application of nutrient solutions such as seaweed increases the quality and quantity of crop and also enhance their storage life and marketability. Various researchers reported that aqueous extracts of seaweed increased the yield and quality of tangerine and orange, strawberry, grape, apple, and watermelon fruit. Thus, the aim of the current study was to investigate the effect of pre-harvest foliar application of Seaweed extract on quality and quantity values, antioxidant properties, and storage life of kiwifruits.Material and Methods This experiment was carried out on 10-year-old kiwifruit vines, in a commercial orchard located in Gilan Province. Vines were selected with uniform size in terms of growth, yield and fruit load, then sprayed with seaweed extract at four levels of 0, 1, 2 and 3 g.l-1 as a foliar spray and control vines only received water. Foliar spraying was performed in three stages, (110, 125 and 140 days after full bloom stage) and Tween 20 was used as a surfactant. This experiment was designed as factorial based on randomized complete block design with three replications. The fruits were harvested in November with soluble solids content (TSS) of 6.5-6.2% and then transferred to the post-harvest physiology laboratory of the University of Zanjan. The treated fruits were stored for 90 days at 1 ° C with 90% RH. Sampling was done at harvest time and after 30, 60 and 90 days of storage and some quantity and quality traits such as weight loss, tissue firmness, TSS, ascorbic acid, total phenol and flavonoids, antioxidant capacity and the activity of superoxide dismutase (SOD) and phenylalanine ammonia-lyase (PAL) enzymes were evaluated.Results and Discussion The ANOVA results showed that seaweed extract, storage time, and interaction of seaweed extract × storage time had a significant effect (p≤0.01) on evaluated traits. All treatments maintained the antioxidant capacity, total phenol and flavonoids content and PAL activity at a higher level compared with control. The amount of fruit tissue firmness, TA and ascorbic acid decreased by increasing the storage time, and at the third month of storage, the lowest amount was observed in the control fruit. Also, comparing the interaction of the mean of treatments and storage time showed that pH, weight loss, TA, TSS, antioxidant capacity, total phenol, flavonoids and PAL enzyme activity increased by increasing the storage time. At the end of the storage time, the highest level of TSS, weight loss and pH were observed in the control fruit. The lowest antioxidant capacity (48.14 %) was observed in the control treatment at harvest time and the highest antioxidant capacity was observed in 3 levels of brown algae extract treatment at the end of storage period. Comparison of means showed that at the first 30 days of storage, the highest PAL enzyme activity was observed in the treatment of 3 g / l of brown algae. PAL enzyme activity significantly increased after the experiment. At the end of storage period, the lowest PAL enzyme activity was observed in control fruit. Treatment of 3 g / l brown algae had higher PAL activity. PAL, as a key enzyme in phenylpropanoid metabolism, catalyzes the conversion of phenylalanine to trans-cinnamic acid, which is the first step in the biosynthesis of phenylpropanoids and leads to the production of secondary metabolites such as lignin, phytolaxoids, and flavonoids. The direct and positive relationship of this enzyme with the synthesis of phenols and flavonoids has been discovered in the fruits of blood orange, strawberry and blueberry. The results of the comparison of the mean showed that the total phenol and flavonoids increased by increasing the storage time. The lowest phenol (23 mg GAE.100 g-1 FW) was observed in control fruit at harvest and the highest (8.88 mg GAE.100 g-1 FW) content of total phenol was observed in 3 levels of brown algae extract at the third month of storage. Plants release phenolic compounds in response to some messenger compounds that play an important defense role. Studies show that there is a positive relationship between total phenol content and their antioxidant activity. Flavonoids are also polyphenolic compounds and are the most important secondary compounds of plants. Under oxidative stress, in plants, the activity of propanoid pathway increases, especially the pathway of flavonoids biosynthesis. Flavonoid compounds are abundant in plants and show antioxidant activity. Seaweed extract enhances the antioxidant capacity of the fruit and thereby inhibits oxygen-free radicals Treatment of 3 g/l seaweed extract had the best effect among the treatments applied in maintaining firmness, fruit weight loss, TA, antioxidant capacity, total phenol and flavonoids and PAL enzyme activity. All three levels of seaweed extract increased the amount of total phenol, flavonoids and antioxidant capacity all over the storage time, but no significant difference was observed among the treatments levels. Based on the results, the application of 3 g/l seaweed extract effectively increased the antioxidant capacity and PAL enzyme activity during 90 days of storage time. As a result, seaweed extract treatment had positive effects on maintaining the quality and increasing the shelf life of kiwifruit during 90 days of storage.ConclusionSeaweed extract is one of the natural compounds and compatible with human health and nature has medicinal and nutritional value that can increase the shelf life and maintain fruit quality in the postharvest period. In summary, foliar application of seaweed extract has a significant effect on fruit firmness, total soluble solids, total acid, vitamin C, phenol and total flavonoids, total antioxidant activity and the enzyme phenylalanine ammonialyase. The appropriate treatment for kiwifruit cultivar ‘Hayward’ is introduced. Among the applied treatments, 3 g/l of seaweed extract had the best effect on firmness (40.40%), fruit weight loss percentage (41.87%), titratable acid (25.37%), vitamin C (33.26%), antioxidant capacity (26.70%), total phenol (81.17%), total flavonoids (103.67%) and PAL enzyme activity (153.75%) compared to the control in 90 days of storage.
