Growing vegetables
Zahra Darabi; Fardin Ghanbari; Javad Erfani moghadam
Abstract
Introduction
Low temperature is one of the most important environmental stresses that cause damage to plants and limit the geographical distribution of plant species. Plants of tropical and sub-tropical origin, such as cucumbers, are sensitive to cold stress and severely damaged at low temperatures. ...
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Introduction
Low temperature is one of the most important environmental stresses that cause damage to plants and limit the geographical distribution of plant species. Plants of tropical and sub-tropical origin, such as cucumbers, are sensitive to cold stress and severely damaged at low temperatures. Plants have evolved a set of defense mechanisms to adapt to low temperatures. These mechanisms include the regulation of gene expression and physiological and biochemical changes that increase plant resistance to chilling stress. Cinnamic acid (CA) is one of the most important phenolic acids present in all plants and has antimicrobial properties against fungi and bacteria. The application of this compound in some plants causes oxidative stress and leads to the activation of antioxidant enzymes. Therefore, in the present study, the effects of exogenous cinnamic acid treatment on cold stress tolerance in cucumber seedlings have been investigated.
Materials and Methods
This research was conducted in the greenhouse and laboratory of the Department of Horticultural Sciences of Ilam University in 2019. Cucumber seeds (Super Daminus cultivar) were planted in a 1: 1: 1 ratio of field soil, manure, and sand. In the fully developed two-leaf stage, seedlings produced were sprayed using cinnamic acid (at concentrations of 0, 50, 100, and 200 μM). Foliar spraying treatments were applied at the mentioned concentrations until the surface of the leaves was completely wet. 24 hours after foliar application, all plants were exposed to cold stress at 3 ° C for 6 hours in six consecutive days. After applying the cold treatment, the seedlings were transferred to the greenhouse and 72 hours later, the traits were measured.
Results and Discussion
The results showed that exogenous CA application increased the growth characteristics of cucumber seedlings subjected to chilling stress. Improving the growth and development of plants under stress conditions by cinnamic acid treatment has been reported in other studies, which is consistent with the results of the present study. It has been reported that cinnamic acid treatment, by causing oxidative shock in plants, leads to plant defensive responses to stress conditions, and through this, plants can better withstand stress conditions. These defense responses include increasing compatible solutions and improving the antioxidant system. In the present study, the use of cinnamic acid treatment increased proline, chlorophyll, and total phenol and reduced of membrane lipid peroxidation, and these changes led to a decrease in the apparent effects of cold on cucumber seedlings.
The use of chemicals that can mitigate the effects of cold on the plant can also help maintain plant growth under cold stress. In the present study, the application of cinnamic acid improved the growth of cucumber seedlings under cold stress conditions. Cinnamic acid pretreatment by inducing antioxidant compounds reduced the effects of cold on cucumber seedlings and improved plant growth in chilling conditions. Also, cinnamic acid treatment increased the growth of pepper plants under salinity stress, cucumber under drought stress, and wheat under drought conditions, which is consistent with the results of the present study. Therefore, it can be said that cinnamic acid improves plant growth under stress by changing physiological and biochemical processes. The results showed that the application of cinnamic acid improved the growth of cucumber seedlings under chilling stress conditions. Cinnamic acid pretreatment caused a significant increase in relative water content (25 to 32%), chlorophyll (108 to 125%), proline (152 to 244%), and total phenol (31%) compared to the control, therefore improving the adaptabilities of cucumber seedlings to chilling stress. The application of cinnamic acid also reduced the damage to cell membranes. The electrolyte leakage and malondialdehyde accumulation of cinnamic acid-treated seedlings were lower than that of control seedlings.
Conclusion
In general, the results of this study showed that the application of cinnamic acid reduced the effects of cold stress on cucumber seedlings. These results were associated with increased proline, chlorophyll, phenol and relative water content, in this way, the rate of ion leakage and accumulation of malondialdehyde in cucumber seedlings were reduced under cold stress. In general, the results showed that cinnamic acid treatment (especially concentration of 200 μM) can effectively reduce the effects of chilling on cucumber seedlings and improve their growth under cold stress.
Mohsen Moradi; Farhang Razavi; Vali Rabiei; Morteza Soleimani Aghdam; Leila Salehi
Abstract
Introduction: In recent years, γ-aminobutyric acid (GABA), a non-proteinogenic four-carbon signaling amino acid, has been employed as a safe strategy for attenuating chilling injury and fungal decay, delaying senescence and keeping sensory and nutritional quality of fruits and vegetables during postharvest ...
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Introduction: In recent years, γ-aminobutyric acid (GABA), a non-proteinogenic four-carbon signaling amino acid, has been employed as a safe strategy for attenuating chilling injury and fungal decay, delaying senescence and keeping sensory and nutritional quality of fruits and vegetables during postharvest life. In addition to applying GABA as exogenous safe procedure, heightening cellular GABA shunt pathway activity also is pivotal for attenuating chilling injury and fungal decay, delaying senescence and keeping sensory and nutritional quality of fruits and vegetables during postharvest life. Low temperature storage is widely employed for prolonging postharvest life of fruits and vegetables accompanying by keeping sensory and nutritional quality. Tomato is one of the most important horticultural crops, which exhibits higher benefits for human health but being endemic to subtropical climates, they are very vulnerable to chilling injury. Cold storage application is normally employed as a regular low-cost real postharvest technology. Owing to its great socio-economic significance, great efforts have been done by researchers to attenuating chilling injury in tomato fruits during low temperature storage employing safe strategies such as melatonin, brassinosteroids, salicylic acid, nitric oxide, and gibberellic acid. Attenuating chilling injury in tomato fruits by postharvest treatments may attribute to keeping safe membrane integrity representing by lower electrolyte leakage and malondialdehyde (MDA) accumulation occurring by eliciting endogenous polyamines, proline and nitric oxide accumulation by activating CBF1 signaling pathway, hampering phospholipase D (PLD) and lipoxygenase (LOX) enzymes activity, activating reactive oxygen species (ROS) scavenging enzymes activity resulting in higher ascorbic acid and glutathione accumulation, maintaining endogenous GA3 homeostasis occurring by higher CBF1 signaling pathway concurrent with higher endogenous salicylic acid accumulation, which not only are pivotal for conferring chilling tolerance in tomato fruits but also are crucial for preserving sensory and nutritional quality.
Material and Methods: Tomato fruits (Solanum lycopersicum cv. Izmir) were picked at the mature green stage in Zanjan Province, Iran, and transported to the fruit analysis laboratory at Zanjan University. In the laboratory, the fruit was screened for uniform size, maturity, and absence of mechanical damage. Fruits (1440) were divided into four groups, each consisting of 360 fruits. The experiment was done in triplicate in which each replicate consisted of 120 fruits. The exogenous GABA applying was done by immersing of fruits in GABA at 0, 0.1, 1, and 5 mM for 15 min at 20 ˚C. Then, fruits were air dried at room temperature and stored at 4 ± 0.5 ºC (85–90 % RH) for 28 days. After assessment of chilling injury every 7 days during storage at 4 ˚C followed by shelf life at 25 ºC for 3 days, biochemical analyses were performed.
Results and Discussion: In recent experiment, we showed that the exogenous GABA applying, especially at 5 mM, is beneficial for attenuating chilling injury in tomato fruits during storage at 4 ºC for 28 days which was associated with higher membrane integrity representing by lower electrolyte leakage and malondialdehyde (MDA) accumulation. Keeping safe membrane integrity in tomato fruits in response to exogenous GABA applying may ascribe to triggering reactive oxygen species (ROS) scavenging catalase (CAT), superoxide dismutase (SOD) and ascorbate peroxidase (APX) enzymes activity giving rise to higher endogenous ascorbic acid accumulation concomitant with promoting phenylpropanoid pathway activity representing by higher phenylalanine ammonia lyase (PAL) enzyme activity giving rise to higher phenols and flavonoids accumulation and superior DPPH scavenging capacity.
Conclusion: Therefore, exogenous application of GABA not only is proficient for attenuating chilling injury but also is beneficial for preserving nutritional quality of tomato fruits during storage at 4 ºC for 28 days.
Mohammad Soleimani; Mostafa Mobli; Ali Akbar Ramin; Bahram Baninasab; Leila Aslani
Abstract
Introduction: Cold stress is one of the limiting factors for plant growth and yield production in most parts of the world. Cold stress damages cells through changes in the activity of macromolecules, decreasing osmotic potential, and significant changes in other parts of the cell. Cold stress in young ...
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Introduction: Cold stress is one of the limiting factors for plant growth and yield production in most parts of the world. Cold stress damages cells through changes in the activity of macromolecules, decreasing osmotic potential, and significant changes in other parts of the cell. Cold stress in young seedlings generally reduces leaf development, induces wilting and chlorosis and in more severe cases, browning and necrosis become visible. Cucumber is a sensitive plant to low temperature and its cultivation, except the southern and central parts of Iran, occurs in areas where there is a possibility of cold stress in the early part of the growing season due to the low temperature. The different ways for controlling cold stress had been used; one of them is using plant growth regulators such as spermidine. Spermidine is one of the polyamines that has been used in recent years to control cold stress. The effect of cold treatment on the amount of indigenous leaf polyamines has been reported differently between cold-resistant and sensitive cucumber cultivars. During the cold stress, the amount of indigenous spermidine in leaves of cold-resistant cucumber cultivars and sensitive cultivars increased significantly and remained unchanged, respectively. The increase in the content of putrescent, spermidine and spermine in cold resistant cultivars during cold stress was probably due to the increased activity of ornithine decarboxylase (ODC). The amount of polyamines in chickpea plants that were exposured to low temperatures (12-15°C and 4-6°C are related to mean maximum and minimum temperature of the farm, respectively) increased six to nine times. Adding spermidine to the cucumber growing medium before applying cold treatment increased spermidine amount in all organs and increased cold tolerance.
Materials and Methods: To study the effect of spermidine on cold tolerance of cucumber, seedling of ‘Rashid’ cultivar, an experiment was conducted based on completely randomized design with four replications and four treatments consist of different concentrations of spermidine (0, 0.1, 0.5 and 1 mM) in incubator of College of Agriculture, Isfahan University of Technology. So seeds were exposed to 20°C for 7 days in a humid condition and then were treated with 0, 0.1, 0.5 or 1 mM spermidine, the remaining 8 days they were kept at 6 or 9°C. The treatments performed in dark conditions until the second day of germination and received 8 hours of light daily from the third day until the end of the experiment. At the end of each experiment, shoot and root length were measured by use of the ruler, shoot and root fresh and dry weight were measured by use of digital scale, shoot and root ion leakage were measured based on Lates method (3) and shoot and root proline concentration were measured based on Bites et al., (2) method. To compare the effects of temperature and its interactions with spermidine, data of two experiments analyzed as split plot experiment (Different temperatures and spermidine concentrations were as main and subplots, respectively).
Results and Discussion: The findings of this study showed that application of the highest concentration of spermidine (1 mM) in 9°C had the inverse effect on cold tolerance, so it decreased the fresh and dry weight of root. In 6°C, 0.5 mM spermidine was more effective than other concentrations, and it increased root fresh weight, shoot proline concentration and decreased root ion leakage. It has been shown that the non-saturated lipid profile of membranes of cold-resistant plants in comparison of non-resistant plants is significantly increased, and this increase is associated with a decrease in cell ion leakage. Proline works as a nitrogen source and soluble substance that helps the plant to combat again stress conditions. The split-plot analysis of data showed that 0.5 and 0.1 mM spermidine treatments increased root length, root fresh and dry weight significantly. The study of spermidine concentrations ×temperatures showed that the increasing effect of 0.5 mM spermidine on root length, root fresh and dry weight was only visible in 6°C.
Mahshid Ghfouri; Ali Soleimani; Vali Rabiei; Roghayeh Hemmati
Abstract
Introduction: Due to high quality, Iran pomegranate is quite competitive compared to other countries is unrivaled among agricultural products and has great economic importance. Using essential oil is a new idea to reduce postharvest losses and increase the horticultural crop storage life and control ...
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Introduction: Due to high quality, Iran pomegranate is quite competitive compared to other countries is unrivaled among agricultural products and has great economic importance. Using essential oil is a new idea to reduce postharvest losses and increase the horticultural crop storage life and control of fungal infection. In this context, a factorial experiment based on completely randomized design was conducted to study the postharvest spraying of thyme essential oil on storage life and qualitative characteristics of pomegranate fruit (cv. Tarom red skin)
Materials and Methods: Pomegranate fruit (cv. Tarom red skin) was prepared and transferred to University of Zanjan, Horticulture postharvest physiology lab. Treatments were included essential oil of thyme at four levels (0, 500, 1000, 1500 mg/l) and the cold time storage (6 °C and 85% of relative humidity) at three levels (one, two and three months (by four replications. In the first experiment, 180 normal pomegranate fruits were treated with thyme essential oil. In the second experiment, fruits were infected with spores of the fungus Aspergillus niger and then treated with essential oil. During experiment, total soluble solids (TSS), titratable acidity (TA), TSS/TA ratio, pH, anthocyanin, electrolyte leakage, chilling injury, weight loss and fungal decay were evaluated. Fruit juice TSS was determined with a hand-refractometer at room temperature. TA was determined by titration an aliquot (20 mL) of the juice with 0.1 N NaOH and the results were expressed as a percentage of citric acid. The maturity index (TSS/TA ratio) was evaluated as the TSS/TA ratio. Fruit juice pH was measured using a pH meter. Anthocyanin was performed to method Fuleki & Francis. Electrolyte leakage was measured according to McCollum & McDonald method. Weight loss was measured according to Ershadi method. Chilling injury was measured by Wang method. Decay was visually evaluated and expressed as percentage. An analysis of variance was used to analyze difference between treatments and the Duncan test was applied for mean separation at p
