Medicinal Plants
M.B. Razavinia; N. Pourghasemian; F. Najafi
Abstract
Introduction
Heavy metals, like cadmium, lead, and arsenic, harm air, soil, agriculture, and human health. Plants suffer from reduced growth, chlorophyll production, and enzyme activity due to heavy metal exposure. Reactive oxygen species are produced, damaging biological molecules. However, ...
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Introduction
Heavy metals, like cadmium, lead, and arsenic, harm air, soil, agriculture, and human health. Plants suffer from reduced growth, chlorophyll production, and enzyme activity due to heavy metal exposure. Reactive oxygen species are produced, damaging biological molecules. However, plants have developed resistance mechanisms, including antioxidant stimulation. Flavonoids, complex compounds in plants, enhance resistance to heavy metals. Medicinal plants, rich in secondary metabolites like flavonoids, phenolic compounds, and alkaloids, show resistance to heavy metals. Origanum majorana as a medicinal plant, contains compounds that contribute to its heavy metal resistance. Based on limited studies, medicinal plants, particularly marjoram, have shown greater resistance to environmental stresses due to their secondary metabolites and the ability to produce uncontaminated essential oils in response to heavy metals like cadmium and lead. This study aimed to investigate the biochemical responses and growth of marjoram plants when exposed simultaneously to cadmium and lead, as well as the mutual effects of these two elements on marjoram behavior.
Materials and Methods
A factorial randomized complete block design experiment with four replications was used to study the effect of Cd in four concentrations (0, 6, 12 and 24 mg.kg-1 soil) as well as Pb in four concentrations (0, 150 300 and 450 mg. Kg-1 soil). The concentrations were determined based on previous reports and a preliminary experiment. Soil was prepared with appropriate amounts of cadmium chloride and lead chloride were added according to the desired concentrations. The contaminated soil was then incubated at field capacity moisture for two months. Seeds have been sown in germination trays. Seedlings at the three to four leaf stage were transferred to pots containing the contaminated soil. Plant harvest took place 42 to 52 days after the transfer to pots, specifically when the plants had just entered the flowering stage. The aboveground parts of the plants were harvested separately, and the roots were carefully removed from the soil. Half of the plants were dried at 105 °C for 24 h to determine the dry weight, Pb and Cd concentrations. The other half of the plants were used to measure biochemical traits including flavonoids, anthocyanins, malondialdehyde, protein, proline and some enzymatic antioxidants. The data was analyzed using a two-way analysis of variance (ANOVA), and the means were compared using the LSD test. A significance level of 95% was applied using SAS 9.2.
Results and Discussion
In this study, various parameters were measured including the dry weight of aerial parts and roots, concentrations of lead and cadmium in the aerial parts and roots, lipid peroxidation (MDA), flavonoids, anthocyanins, total phenols, proline, protein, and antioxidant enzymes including guaiacol peroxidase (GPX), ascorbate peroxidase (APX), and catalase (CAT). The results of the analysis of variance showed that all the mentioned traits were influenced by the individual effects of lead and cadmium. However, there was no significant interaction between cadmium and lead on proline, protein, GPX, polyphenols, flavonoids, and anthocyanins. The dry weight of aerial parts and roots decreased in the presence of cadmium and lead, while the concentrations of lead and cadmium increased. However, this damage was more pronounced in the presence of cadmium compared to lead. The presence of cadmium in a lead-containing environment had an inhibitory effect on lead uptake by the plant, and vice versa. The highest level of MDA was reported in the combination of lead and cadmium concentrations of 450 and 24 mg/kg, respectively. The analysis of enzyme activity showed that the maximum catalase activity was observed in the combination of 6 and 450 mg/kg of cadmium and lead, respectively, while the minimum activity was found in the control group. Similarly, the highest APX activity was reported in the combination of 24 mg/kg of cadmium and zero lead, while the lowest activity was observed in the control group. The use of cadmium and lead at the highest consumption level compared to the control group resulted in a 204% and 40% increase in GPX activity, respectively. In the analysis of total phenols, flavonoids, anthocyanins, and protein, an increase in cadmium concentration from zero to 24 mg/kg led to a decrease of 52%, 42%, 208%, and 81%, respectively, while protein decreased by 39%. These traits showed an increase of 14%, 14%, 58%, and 40%, respectively, with an increase in lead concentration from zero to 450 mg/kg, while protein decreased by 24%. Based on the results, it appears that the increase in secondary metabolites with the increase in heavy metals has accompanied the plant's response to the prevailing conditions.
Conclusion
The study found that both cadmium and lead negatively affect the dry weight of plants, with cadmium having a greater impact. This reduction is particularly noticeable in photosynthesis, pigments, electron transport chain, and energy production. The highest concentrations of lead and cadmium (24-450 mg/kg) show the maximum decrease. As the concentrations of these elements increase in the growth medium, their concentration in the plants also increases. Lead has lower mobility and tends to accumulate in the roots compared to cadmium. Interestingly, the presence of cadmium inhibits the uptake of lead by the plant, and vice versa. This leads to an average inhibition of 39% for lead uptake by cadmium and 35% for cadmium uptake by lead in the aerial parts. The study also observed an increase in secondary metabolites, which act as antioxidants and help the plant cope with the stresses caused by cadmium and lead. These metabolites may also contribute to osmotic regulation along with the increase in proline. Based on these findings, it seems that these plants can be used in green spaces contaminated with moderate to low levels of cadmium and lead, particularly in mining areas.
Growing vegetables
Leyla Cheheltanan; Saeed Khosravi; Hosein Nemati
Abstract
IntroductionGrasses are narrow-leaved plants that are used as cover plants in landscape. These plants are one of the basic and necessary components of the green cover of most gardens, parks and as the background color of landscape. In Iran, due to the high costs of planting and management of grass, high ...
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IntroductionGrasses are narrow-leaved plants that are used as cover plants in landscape. These plants are one of the basic and necessary components of the green cover of most gardens, parks and as the background color of landscape. In Iran, due to the high costs of planting and management of grass, high water requirements, climatic incompatibility and damage to water and soil salinity, it is recommended to remove from the green space in some cities, especially in areas with low water and water and soil saline. If it is possible to benefit from the role and influence of these plants by observing the technical points and choosing the best species for each area. Salinity stress is the second limiting factor for the growth of plants in the world after drought, which affects the efficiency and performance of plants. Increase in salinity causes a decrease in the water potential in the soil. In this condition, the plant spends most of its energy to maintain the water potential, cell mass, and water absorption to have minimal growth. The aim of this research is the effect of external application of glycine betaine on the accumulation of osmolality compounds and the antioxidant system of sports grass under salt stress. Materials and MethodsThis research was done in factorial form in completely randomized design with 3 replications on Rashid variety cucumber. The factors included 4 levels of temperature (25, 30, 35 and 40 degrees Celsius) and 3 levels of salicylic acid (0, 0.5 and 1 mM). When the seedlings reached the two-leaf stage, they were sprayed with different concentrations of salicylic acid two times with an interval of five days. One week after the application of salicylic acid, temperature treatment was gradually applied. After applying each heat treatment, the corresponding pots were transferred to the greenhouse with a temperature of 25 degrees Celsius. Then, fresh and dry weight of root and shoot, leaf surface, chlorophyll index, electrolyte leakage, proline, polyphenol oxidase enzyme activity and superoxide dismutase enzyme activity were measured. Results and Discussion The results showed that salinity stress decreased all the study morphological, physiological and biochemical parameters including plant height, shoot fresh and dry weight, number of tiller, leaf area, chlorophyll content, protein and total antioxidant capacity in the studied plants. It also increased peroxidase enzyme, H2O2 and proline in plants, but glycine betaine application significantly improved the morpho-physiological characteristics of plants compared to the control under salt stress conditions. Thus, the highest height, shoot fresh and dry weight, leaf area, number of tiller, chlorophyll content, and protein and antioxidant capacity were observed in plants sprayed with glycine betaine. Also, the highest content of glycine betaine and activity of catalase and peroxidase enzymes and the lowest content of glycine betaine and H2O2 were observed in in plants sprayed with glycine betaine and 10 mM glycine betaine was more effective than 5 mM. The occurrence of salinity in plants disrupts the absorption of ions and causes the reduction of nutrients and increases sodium ions. One of the effects of salinity in plants is the reduction of photosynthetic activity, which results in the reduction of chlorophyll, carbon dioxide absorption, photosynthetic capacity, plant height, shoot fresh and dry weight, number of tiller and leaf area. One of the most strategies to deal with stress is accumulation of osmolyte and increasing the antioxidant activity, which makes plants resistant to environmental stresses. Salinity, through the toxic effect of Na+ and Cl- ions, affects the growth and performance of the plant by reducing the soil water potential, disrupting water absorption and imbalance of nutrients in the plant. The results obtained from comparing the average results of glycine betaine show that glycine betaine increased plant height, shoot fresh and dry weight, number of tiller, leaf area, chlorophyll content, total protein and antioxidant capacity, but on the other hand, it increased proline and H2O2 decreased, which is due to the accumulation of glycine betaine as a protector in plants under salt stress conditions. In stress conditions, glycine betaine can protect photosynthetic activities including photosynthetic enzymes, proteins and lipids in thylakoid membranes in the combination of photosystem II, and also the task of protecting cell membranes against osmotic stresses in the plant. ConclusionThe results obtained from this research showed that salinity stress reduced all the morphological, physiological and biochemical characteristics in the sport grass plants, but glycine betaine application played a positive role in reducing salinity damage and maintaining plant quality. Glycine betaine is known as one of the effective molecules in stress signaling, so it can protect the plant cells against stress by reducing the destruction of the membrane and by increasing the salt tolerance mechanisms. Also, glycine betaine 10 mM is introduced as the best treatment to reduce salinity damage in sport grass during present study.
Ornamental plants
Meisam Mohammadi; Fatemeh Khosravifar; Negin Siahi
Abstract
IntroductionGrasses are narrow-leaved plants that are used as cover plants in landscape. These plants are one of the basic and necessary components of the green cover of most gardens, parks and as the background color of landscape. In Iran, due to the high costs of planting and management of grass, high ...
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IntroductionGrasses are narrow-leaved plants that are used as cover plants in landscape. These plants are one of the basic and necessary components of the green cover of most gardens, parks and as the background color of landscape. In Iran, due to the high costs of planting and management of grass, high water requirements, climatic incompatibility and damage to water and soil salinity, it is recommended to remove from the green space in some cities, especially in areas with low water and water and soil saline. If it is possible to benefit from the role and influence of these plants by observing the technical points and choosing the best species for each area. Salinity stress is the second limiting factor for the growth of plants in the world after drought, which affects the efficiency and performance of plants. Increase in salinity causes a decrease in the water potential in the soil. In this condition, the plant spends most of its energy to maintain the water potential, cell mass, and water absorption to have minimal growth. The aim of this research is the effect of external application of glycine betaine on the accumulation of osmolality compounds and the antioxidant system of sports grass under salt stress. Materials and Methods This research was carried out in 2022 in pots in the research greenhouse of Ilam University as a factorial based on a completely random design with three replications. Experimental treatments included three salinity levels with sodium chloride salt (without salinity, 50 and 100 mM sodium chloride) and three levels of glycine betaine foliar spraying (0, 5 and 10 mM). Glycine betaine application was performed after mowing twice with a distance of 48h from each other, and then salinity with sodium chloride salts was applied. 4 weeks after application of salinity stress, some morphological and biochemical characteristics of plants were measured. The results were analysed using SAS software (v.9.2), and Tukey's test was used to compare the means at the 5% probability level. Results and DiscussionThe results showed that salinity stress decreased all the study morphological, physiological and biochemical parameters including plant height, shoot fresh and dry weight, number of tiller, leaf area, chlorophyll content, protein and total antioxidant capacity in the studied plants. It also increased peroxidase enzyme, H2O2 and proline in plants, but glycine betaine application significantly improved the morpho-physiological characteristics of plants compared to the control under salt stress conditions. Thus, the highest height, shoot fresh and dry weight, leaf area, number of tiller, chlorophyll content, and protein and antioxidant capacity were observed in plants sprayed with glycine betaine. Also, the highest content of glycine betaine and activity of catalase and peroxidase enzymes and the lowest content of glycine betaine and H2O2 were observed in in plants sprayed with glycine betaine and 10 mM glycine betaine was more effective than 5 mM. The occurrence of salinity in plants disrupts the absorption of ions and causes the reduction of nutrients and increases sodium ions. One of the effects of salinity in plants is the reduction of photosynthetic activity, which results in the reduction of chlorophyll, carbon dioxide absorption, photosynthetic capacity, plant height, shoot fresh and dry weight, number of tiller and leaf area. One of the most strategies to deal with stress is accumulation of osmolyte and increasing the antioxidant activity, which makes plants resistant to environmental stresses. Salinity, through the toxic effect of Na+ and Cl- ions, affects the growth and performance of the plant by reducing the soil water potential, disrupting water absorption and imbalance of nutrients in the plant. The results obtained from comparing the average results of glycine betaine show that glycine betaine increased plant height, shoot fresh and dry weight, number of tiller, leaf area, chlorophyll content, total protein and antioxidant capacity, but on the other hand, it increased proline and H2O2 decreased, which is due to the accumulation of glycine betaine as a protector in plants under salt stress conditions. In stress conditions, glycine betaine can protect photosynthetic activities including photosynthetic enzymes, proteins and lipids in thylakoid membranes in the combination of photosystem II, and also the task of protecting cell membranes against osmotic stresses in the plant. ConclusionThe results obtained from this research showed that salinity stress reduced all the morphological, physiological and biochemical characteristics in the sport grass plants, but glycine betaine application played a positive role in reducing salinity damage and maintaining plant quality. Glycine betaine is known as one of the effective molecules in stress signaling, so it can protect the plant cells against stress by reducing the destruction of the membrane and by increasing the salt tolerance mechanisms. Also, glycine betaine 10 mM is introduced as the best treatment to reduce salinity damage in sport grass during present study.
Pomology
N. Zeinoldini; H.R. Karimi; F. Nazoori; S.R. Sahhafi
Abstract
Introduction
Pistachio is one of the most important horticultural crops in Iran. Most pistachio orchards are located in arid and semi-arid regions of Iran, which have a lack of irrigation water. Drought stress is considered as one of the most important limiting factors for the production of plants in ...
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Introduction
Pistachio is one of the most important horticultural crops in Iran. Most pistachio orchards are located in arid and semi-arid regions of Iran, which have a lack of irrigation water. Drought stress is considered as one of the most important limiting factors for the production of plants in dry areas. Pistachio (P. vera L.) is one of the drought-resistant fruit trees due to its deep roots, but it has been reported that water stress reduces the yield and dry quality of this product. The degree of resistance to drought stress in pistachios depends on the type of rootstock, so the evaluation of pistachio species from the point of view of the rootstock is important.
Material and Methods
In order to evaluate the resistance of four pistachio rootstocks to drought stress, a factorial experiment in a completely randomized design with two drought factors at three levels (3, 6 and 9 days irrigation intervals) and a rootstock at four levels, 'Badami- e- Riz-e-Zarand', 'Ghazvini', Eurycarpa (Pistacia euricarpa), and an interspecific hybrid (P. vera × P. terebinthus) with three replications were performed under greenhouse conditions. Hybrid rootstocks produce in a breeding program using hybridization of P. vera and P. terebinthus. At the end of the experiment, the growth parameters including the number of leaves, leaf area, stem height, as well as stem diameter at a height of one centimeter above the soil surface, leaf fresh and dry weight, shoot fresh and dry weight, and root fresh and dry weight, as well as physiological and biochemical parameters including chlorophyll fluorescence (FV/FM), SPAD index, PI, Cha, Chb, total chlorophyll and carotenoids, RWC, proline, soluble carbohydrates, and phenolic compounds and concentrations of Calcium, Magnesium, Potassium and Iron elements in leaves were measured.
Results and Discussion
The results showed that drought stress reduced growth and physiological indices so that the lowest reduction in shoot dry weight was related to the hybrid rootstock and the highest reduction was related to 'Ghazvini'. It has been reported that the height and diameter of the stem of pistachio seedlings decrease significantly with the increase in irrigation period. This decrease can be attributed to the reduction of the cell turgor pressure under stress. In response to drought stress, the content of proline and soluble carbohydrates in the leaves of the studied rootstock increased. The results of this study are in line of other studies on pistachio. The highest content of proline and the lowest content of soluble carbohydrates were observed in 'Badami- e- Riz-e-Zarand’. The highest content of soluble carbohydrates belonged to Eurycarpa and hybrid rootstocks. The reason for the increase of soluble carbohydrates in the present study can be due to the decrease in the amount of photosynthesis. Drought stress exerted an influence on the nutrient concentrations within both shoots and roots, leading to an increase in potassium content. The highest concentrations of potassium in shoots and roots were noted in the Eurycarpa and hybrid rootstocks, respectively. This elevation in potassium concentration in both roots and shoots could be attributed to active absorption of this element. Plants enhance potassium absorption by expending energy to sustain stomatal conductance, cell turgor pressure, and osmotic regulation.
Conclusion
Drought stress is considered one of the most important environmental stresses, the first effects of which appear in plants in the form of reduced growth and disturbance in physiological parameters. Based on the present study, most of the measured parameters were subjected to drought treatment and the investigated rootstocks showed different reactions, so that hybrid and Eurycarpa rootstocks were less affected by drought stress than other rootstocks. According to the results of the present study, it can be postulated that Eurycarpa and hybrid rootstocks have a high potential for drought resistance.
Growing vegetables
J. Panahandeh; M.S. Zare far; A. Motallebi-Azar; F. Zare Nahandi; M. Amani
Abstract
IntroductionVarious methods of stress directly affected the growth and production yield of numerous plants. For example, environmental stress reduces the tomato manufacturing by the disrupting its natural metabolism, or, salinity stresses affect the it is growth and development from the germination stage ...
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IntroductionVarious methods of stress directly affected the growth and production yield of numerous plants. For example, environmental stress reduces the tomato manufacturing by the disrupting its natural metabolism, or, salinity stresses affect the it is growth and development from the germination stage to the fruit ripening stage. Salinity in tomatoes by stimulating the biosynthesis of growth regulators such as ethylene and abscisic acid leads to the acceleration of the aging of the leaves. Therefore, development of different methods to induce salinity stress tolerance in plants is necessary. Some approaches were studied to develop the salinity tolerant plants such as genetic breeding, environmental improvements and usage of phytohormones and signal molecules. Salicylic acid or orthohydroxybenzoic acid plays an important role in regulating the physiological and biochemical responses of plants to stress conditions, which improves the plant's resistance to adverse environmental conditions. For instance, salicylic acid is a facile and effective way to increase plant productivity under salt stress conditions. Considering the positive effects of salicylic acid in modulating the effects of salinity, this study was conducted with the aim of investigating the effects of salicylic acid’s usage in modulating the harmful effects of salinity on some vegetative, physiological, quantitative and qualitative characteristics of two tomato cultivars of Baneh local mass and Semi Dwarf line.Materials and MethodsTo investigate the effect of salicylic acid in modulating the effects of salinity stress in tomato, a factorial experiment was conducted in the form of a randomized complete block design, with 12 treatments, in 3 replications and with a total of 36 experimental units in the hydroponic greenhouse of the Department of Horticulture, Faculty of Agriculture, and university of Tabriz. The treatments included two levels of salicylic acid (0 and 1 mM) and salinity levels (0, 35 and 70 mM NaCl) on two tomato cultivars of Baneh and Semi Dwarf.Results and DiscussionThe results showed that in Baneh and Semi Dwarf cultivars, the increase in salinity levels caused a decrease in vegetative indices, meanwhile the treatment of salicylic acid along with salt stress increased same indices. Also, salt stress caused yield reduction in both Baneh and Semi Dwarf cultivars. By examining the qualitative indicators, it was observed that titratable acidity and vitamin C increased with salt stress and salicylic acid treatment in both cultivars. In terms of physiological indicators, the amount of proline increased at different salinity levels with salicylic acid treatment, but the amount of leaf chlorophyll index decreased with the increase of same condition.ConclusionThe results of testing the effect of salicylic acid and the effects of salinity stress on vegetative, quantitative, qualitative and physiological indicators in Baneh and Semi Dwarf tomatoes showed a remarkable difference in terms of significance. In terms of vegetative traits; Plant height, leaf area index, shoot wet in Baneh and Semi Dwarf cultivars decreased with increasing salinity levels of vegetative indices, but salicylic acid treatment along with salinity stress increased same indices. Indicators such as yield, fresh weight of fruit, and percentage of dry matter of fruit showed different responses to different levels of salinity and salicylic acid treatment. The fresh weight of fruit increased with the application of salicylic acid. Also, salt stress caused an increase in the percentage of dry matter of the fruit. But salt stress caused yield reduction in both Baneh and Semi Dwarf cultivars. In terms of quality indicators; the amount of titratable acidity and vitamin C increased with salt stress and salicylic acid treatment in both cultivars. In terms of physiological indicators, the level of proline increased across various salinity levels with salicylic acid treatment. However, the leaf chlorophyll index decreased with rising salinity levels, even in the presence of salicylic acid treatment. Overall, salinity stress caused a decrease in most analyzed traits in the Baneh and Semi Dwarf cultivars. Nevertheless, it led to improvements in certain quality traits. Additionally, salicylic acid treatment enhanced the mentioned indices in most of the examined traits in both cultivars. Therefore, considering the positive effects of salicylic acid treatment on Baneh and Semi Dwarf cultivars under salinity stress conditions, its use is recommended.
Growing vegetables
N. Zeinali Pour; F. Aghebati; B. Nejhad Shahrokh Abadi
Abstract
Introduction
Recently, the market demand for high quality tomato fruit is increasing. This product is one of the most important vegetables produced all over the world, and in the last few decades, there has always been a growing trend for its production and consumption. Today, seedling production is ...
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Introduction
Recently, the market demand for high quality tomato fruit is increasing. This product is one of the most important vegetables produced all over the world, and in the last few decades, there has always been a growing trend for its production and consumption. Today, seedling production is considered as a specialized and profitable industry all over the world, which also has a good development speed in our country. The production of healthy and strong seedlings is a prerequisite for proper plant growth and economic production, and nutrition plays an important role in this. Today, the use of natural and organic compounds in various sectors of production and agriculture is increasing. One of these organic compounds, is γ-aminobutyric acid. Biofertilizers are used in order to reduce the consumption of chemical fertilizers and thus reduce the negative environmental effects and increase the yield of plants in agricultural systems. Salicylic acid is a natural phenolic compound and one of the endogenous plant regulators that exists in most plants and is an important component in the signaling pathway. Salicylic acid is effective in regulating the process of plant growth and development, germination, flowering, opening and closing of stomata, respiration, absorption and transfer of ions, photosynthesis, maintaining membrane integrity and plant growth rate. The objective of this study was to examine the influence of varying concentrations of γ-aminobutyric acid and salicylic acid compounds on the physiological attributes, photosynthetic components, and quality traits of Lycopersicum esculentum cv. Seyran seedlings. The aim was to identify the most effective concentration of these hormonal and pseudo-hormonal compounds under the specific conditions of this research.
Materials and Methods
This experiment was conducted in 2017 in the research greenhouse of Shahid Bahonar University of Kerman as a factorial in a completely randomized design with three replications. Lycopersicum esculentum cv. Seyran seeds were planted and after the seedlings reached the stage of three to four leaves and were well established, the first foliar spraying was done with complete NPK fertilizer containing other micronutrients. After 75 % of the seedlings reached the five leaf stage, foliar spraying of the treatments with γ-aminobutyric acid with concentrations of 0, 5 and 10 mg/l and half an hour later with salicylic acid with concentrations of 0, 0.5 and 1.5 mM was performed. After 15 days, the second foliar spraying steps of the treatments were repeated. Traits studied include; seedling stem diameter, ion leakage, relative water content, total chlorophyll, yield, stomatal conductance, net photosynthesis rate, catalase, peroxidase, proline and malondialdehyde.
Results and Discussion
Based on the results of analysis of variance, the simple effect of GABA and the simple effect of salicylic acid on seedling diameter, ion leakage and total chlorophyll were significant at the level of one percent and their interaction was significant at the level of five percent. In the of relative water content and yield, the simple effects of GABA and salicylic acid, as well as the interaction of the two, were significant at the 1% level (Table 1). Results showed that the largest plant diameter and relative water content in GABA 10 mg/l and with the combined use of 1.5 mM salicylic acid and the lowest plant diameter and relative water content in the condition of not using GABA and using salicylic acid in the amount 0.5 mM was obtained. Also, the highest amount of ion leakage occurred in the control plants and the lowest amount of ion leakage is related to the treatment of 10 mg/l GABA combined with 1.5 mM salicylic acid. Investigations showed that a increase in performance compared to the control occurs when using the combination of GABA 10 mg/l along with 0.5 and 1.5 mM salicylic acid (Table 3). According to the analysis of variance results, both the individual effects of γ-aminobutyric acid (GABA) and salicylic acid on leaf stomatal conductance and net photosynthesis rate were found to be significant at the one percent level, with their interaction being significant at the five percent level. Furthermore, the analysis revealed that the individual and combined effects of GABA and salicylic acid on catalase enzyme activity were significant at the five percent level. Additionally, the individual effect of GABA at the one percent level, the individual effect of salicylic acid, and their combined effect on malondialdehyde levels were all significant at the five percent level (refer to Table 2). According to the average comparison results, the highest level of leaf stomatal conductance was observed in the concentration of 1.5 mM salicylic acid in all three application levels of GABA, and the interaction treatment of 10 mg/l GABA with 1.5 mM salicylic acid had the highest net photosynthesis rate and activity of catalase and peroxidase enzymes. The highest amount of proline accumulation occurred in the treatment combination of GABA 10 mg/l along with each of the three concentrations of salicylic acid. The highest accumulation of malondialdehyde was observed in the control sample (without the use of γ-aminobutyric acid and salicylic acid) and the lowest amount of this characteristic was obtained in the combined treatment of GABA 10 mg/l with 0.5 mM salicylic acid (Table 4).
Conclusion
In summary, the utilization of γ-aminobutyric acid as a biological compound and salicylic acid as a growth regulator exhibited a beneficial impact on most of the studied traits in Lycopersicum esculentum cv. Seyran seedlings. This included enhancements in seedling diameter, relative water content, total chlorophyll levels, yield, catalase and peroxidase enzyme activity, proline content, as well as reductions in ion leakage and malondialdehyde levels. It appears that the highest applied concentration of GABA (10 mg/l) and the highest concentration of salicylic acid (1.5 mM) yielded the most favorable results, effectively improving seedling production while preserving its quality.
Medicinal Plants
A. Najarzadeh; H. Farahbakhsh; M. Naser Alavi; R Moradi; M. Naghizadeh
Abstract
Introduction
Borage (Borago officinalis L.) is a valuable annual medicinal herb suitable for cultivation in many countries, including Iran. Borage is considered as a native of both Europe and Asia. Several species around the world fall under the denomination of “borage”. The presence of ...
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Introduction
Borage (Borago officinalis L.) is a valuable annual medicinal herb suitable for cultivation in many countries, including Iran. Borage is considered as a native of both Europe and Asia. Several species around the world fall under the denomination of “borage”. The presence of the γ-linolenic acid in the seeds of borage makes borage distinctively important mainly for the nutraceutical and pharmaceutical research. γ-Linolenic acid is an omega -6 polyunsaturated fatty acid which cannot be synthesized in the body and hence falls into the category of essential fatty acids (Evesh et al., 2019).
Chemical fertilizer is an indispensable abiotic factor in agricultural production, especially nitrogen fertilizer. However, in order to improve the yield, people fertilize a lot, which not only wastes resources, but also brings a series of serious problems to the environment, such as greenhouse gas emissions, soil fertility degradation and water resources pollution. Therefore, developing new fertilizers, improving crop nutrient utilization efficiency, replacing chemical fertilizers and reducing environmental pollution is an important direction of agricultural sustainable developme (Zhang et al ., 2020).
Biochar is a carbon rich product formed by pyrolysis of agricultural and forestry wastes under limited air availability. It is generally alkaline in nature, with the characteristics of rich carbon content, large specific surface area and strong adsorption. Biochar addition can reduce soil bulk density and increase porosity, pH, water holding capacity and nutrient content. Additionally, the unique physical properties of biochar can also promote the colonization and growth of some specific microorganisms, which may participate in the mineralization of biochar and promote nutrient cycling. Therefore, biochar has been widely used on improving soil quality and increasing crop productivity. Biochar has a positive effect on root structure and nutrient absorption of plant. Several studies have shown biochar can significantly increase the root length, root biomass, root surface area and specific root length. The study also found that biochar significantly increased the number of plant root tips, the most active part of root, and then increased the ability of plants to absorb nutrients from soil (Zhang et al, 2020).
Materials and Methods
In order to evaluate the effect of damask rose waste (DRW), walnut green skin waste (WGW) and cow manure biochars on biochemical, physiological and yield characteristics of European borage, an experiment was carried out based on a completely randomized design at the greenhouse conditions in Faculty of Agriculture, Shahid Bahonar University of Kerman. The experimental treatments contain: without of biochar (control), biochars of cow manure (0.75%, 1.25%, 2.5% and 5% w/w), walnut green skin biochar (WGW) (0.75%, 1.25%, 2.5% and 5% w/w) and damask rose waste biochar (DRW) (0.75, 1.25, 2.5 and 5% w/w). The physicochemical properties of the biochars and soil were analyzed. Five seeds were planted in three-kilogram pots at a depth of 1.5 to 2 cm. The greenhouse was maintained at an average temperature of 25 °C during the day and 20 °C at night, with a relative humidity level of 60%. Upon concluding the experiment, various biochemical, physiological, and functional characteristics of European borage were assessed and measured.
Results and Discussion
The results showed that DRW (60%) and WGW (13%) biochars had the highest and lowest amount of stable organic carbon, respectively. The investigated treatments significantly (p≤ 0.01) affected the biochemical, physiological and performance traits of European borage. Application of DRW and manure biochars caused a significant (p ≤ 0.01) increase in yield and photosynthetic pigments of European borage compared to the control. Applying WGW biochar at the level of 2.5% increased the shoot dry weight of the plant by 119% compared to the control treatment. Application of 1.25% of cow manure biochar also increased the shoot dry weight by 29.7%. WGW biochar applying not only had no positive effect on the growth and yield of the European borage, but also lead the decreasing growth and prevent flower production of borage. The highest CAT activity related to applying 2.5% of DRW biochar and 1.25% of manure biochar. Application of WGW in concentration of 0.75% significantly increased the proline contents. Using biochar improves soil fertility.
Conclusion
In general, applying DRW biochar in concentration of 2.5% and cow manure biochar in concentration of 1.25% were the most suitable treatments.
Growing vegetables
M. Ghoreyshi; F. Nekounam; T. Barzegar; J. Nikbakht
Abstract
Introduction
Water stress is the most prominent abiotic stress limiting agricultural crop growth and productivity. Deficit irrigation stress as a consequence of the progressive decrease in water availability has been a hot topic regarding food security during the last two decades. Growth and development ...
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Introduction
Water stress is the most prominent abiotic stress limiting agricultural crop growth and productivity. Deficit irrigation stress as a consequence of the progressive decrease in water availability has been a hot topic regarding food security during the last two decades. Growth and development of plants is influenced by reduction in turgor that results in decreased nutrient acquisition from dry soil. When water supply is limited, plant growth and yield is reduced and plant structure is modified by decreasing in leaf size. The effect of deficit irrigation on fruit yield and quality has been reported by numerous researchers with different results. In melon, deficit irrigation reduced marketable fruit number and yield, average fruit weight, fruit diameter and did not affect rind thickness and seed cavity, but increased total soluble solids content. Although the effects of water stress have been studied on growth and yield of different crops during the last years, recent information on the response of African horned cucumber yield and quality to deficit irrigation remains limited, particularly about the results of restricted water distributions in arid and sub-arid environments. The main goal of this study was to evaluate the effect of controlled deficit irrigation on growth, physiological parameters and yield and fruit quality of African horned cucumber.
Material and Methods
Field experiment was performed based on a completely randomized block design with three irrigation regimes (60, 80 and 100 %ETc), whit three replications at Research Farm of University of Zanjan during the 2019. The African horned cucumber seeds were sown on 1th July 2020 at recommended spacing of 50 cm in row with 120 cm between rows. The irrigation system consisted of one drip line every crop row. The three irrigation levels were calculated based on actual evapotranspiration (ETc): (1) control, irrigated 100% crop water requirement, (2) deficit irrigation 80% ETc and (3) deficit irrigation 60% ETc. The Water requirement of the plant for control treatment was estimated using long-term average daily data of meteorological parameters recorded at Zanjan Meteorological Station and following relation. Before starting the differential irrigation at five-leaf stage, all treatments were supplied with similar amount of water to maximize stands and uniform crop establishment. During plant growth, the relative water content, proline content, electrolyte leakage, chlorophyll and carotenoids, P and K contents were measured. After fruit harvest, vine length of each plant, leaf dry weight and stem diameter were measured. The fruits were harvested when color changed from green to yellow. Fruit weight, fruit number per plant and fruit yield per plant was measured. Immediately after harvest, fruit firmness, total soluble solid, total phenols content, antioxidant capacity and vitamin C were determined.
Results and Discussion
As the results showed water deficit stress significantly reduced plant length, chlorophyll content, and increased carotenoids content. Based on the findings, deficit irrigation caused a significant reduction in leaf relative water content. According to the results, phosphorus and potassium contents in African horned cucumber leaves decreased with deficit irrigation treatments. The highest P and K contents were found under irrigation 100 %ETc treatment. Drought stress and associated reduction in soil moisture can decrease plant nutrient uptake by reducing nutrient supply through mineralization. The proline content increased with the deficit irrigation treatments; in particular with sever deficit irrigation (60 %ETc). Mean comparisons of data showed that deficit irrigation led to a significant increase in electrolyte leakage compared to control.
Water deficit stress caused significant reductions in yield. The highest fruit number per plant and yield were obtained under irrigation 100% ETc. The average fruit weigh significantly increased in response to increase water deficit stress. Deficit irrigation treatments significantly decreased vitamin C and fruit firmness. Significant differences among irrigation treatments were observed for total phenols and total soluble solid contents. The phenols and total soluble solid contents increased with the decrease of irrigation water applied. Antioxidant capacity was affected significantly by the irrigation treatments, and water deficit stress increased antioxidant capacity, which no significant difference was observed between irrigation 100 and 80 %ETc.
Conclusion
Water deficit has been shown to adversely affect plant growth, fruit yield, and leaf water status of African horned cucumber, but led to increase the TSS and antioxidant capacity. According to the results, fruit yield reduced 13.9 % under irrigation 80% ETc compared to irrigation 100% ETc, However, water consumption was saved by 20% and improved fruit weight and fruit quality with increasing soluble solids and antioxidant capacity.
Growing vegetables
S. Parsajoo; F. Dashti
Abstract
Introduction
Plants are sometimes exposed to several stresses during their growth and development. Salinity stress is one of the most common abiotic stresses that significantly reduces the growth and yield of most plant species. A large part of the soils and a significant volume of all water resources ...
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Introduction
Plants are sometimes exposed to several stresses during their growth and development. Salinity stress is one of the most common abiotic stresses that significantly reduces the growth and yield of most plant species. A large part of the soils and a significant volume of all water resources in Iran are affected by salinity to varying degrees. Due to the rapid population growth and the need for more food and the water crisis, the use of unconventional water such as salt water or wells and treated wastewater in agriculture has received more attention. Soil and water salinity is one of the integrative problems in agriculture and is one of the most important barriers to crop production in the world. Salinity stress reduces the ratio of carbon dioxide to oxygen in the leaves by closing the leaves stomata and prevents the stabilization of carbon dioxide. Under these conditions, the formation rate of reactive oxygen species in chloroplasts and mitochondria increases, the electrons produced react with oxygen by photosynthesis and lead to the production of oxygen free radicals. These affects the growth, yield and quality of agricultural products. The use of antioxidant compounds can moderate the effects of this stress. Many compounds have been used to reduce the harmful effects of salinity stress. Ascorbic acid is a water soluble antioxidant and has some effects on plant resistance against environmental stresses by neutralizing free radicals. Researches showed that ascorbic acid increased plant resistance on various stresses such as salinity and drought. It has been widely used to control the effects of salinity stress. The aim of this study was to investigate the effect of ascorbic acid on resistance to salinity stress in bell pepper seedlings.
Materials and Methods
This study was done as a factorial experiment in a completely randomized design including ascorbic acid treatment (0, 1, 3 and 5 mM) and salinity stress of sodium chloride (0 and 100 mM) in 3 replications. The seeds of bell pepper Cv. California Wonder were planted in a seedling tray containing cocopeat. After emergence of cotyledons, they were fertilized with complete fertilizer (N20, P20, K20). At the stage of three true leaves the salinity treatment were started. One week before the beginning of salinity treatment, ascorbic acid was sprayed on plants and repeated two more times by seven days interval. Salinity treatment was applied by irigation for three weeks. After producing 5 leaves, a few growth properties (plant fresh and dry weight, root fresh and dry weight, leaf number and leaf area), biochemical characteristics (amounts of total chlorophyll, proline, soluble proteins, ion leakage and malondialdehyde and activity of Catalase an Proxidase enzymes) and amounts of some elements (K, P, Na, Fe, Zn and Cu) were measured.
Results and Discussion
Based on the results, the simple effect of salinity stress, ascorbic acid and the combined effect of them on ion leakage and amounts of malondialdehyde were significant at the level of 1% probability. Salinity stress increased the amounts of ion leakage and malondialdehyde and application of 5 mM ascorbic acid reduced the amount of these traits to 41.01% and 46.58% compared to the control respectively. The effect of salinity stress, ascorbic acid and the combined effect of them on the concentration of proline and chlorophyll in the leaves of bell pepper were significant at the level of 1% probability. Salinity stress increased the amount of proline but decreased chlorophyll and leaf protein of pepper seedlings and application of 5 mM ascorbic acid increased them to 79.42% and 46.57% compare to control respectively. Under salinity stress the uptake of iron, zinc, copper and phosphorus decreased; using of 5 mM ascorbic acid increasing accumulation of these elements in leaves .On the other hand ascorbic asid could decrease the amounts of sodium accumulation in seedling,s leaves. The results showed that, salinity decreased growth indices (number of leaves, leaf surface, fresh weight of roots and plants) and ascorbic acid reduced the effect of salinity stress on growth parameters. Under salinity stress, 5 mM ascorbic acid treatment increased the leaf surface to 36.30% compared to salinity without ascorbic acid tretment. The effects of salinity stress and the combined effect of salinity stress and ascorbic acid on the amount of catalase and peroxidase enzymes were significant at the level of 1% probability. The effect of ascorbic acid was significant for catalase at 5% probability level and peroxidase at 1% probability level. Although salinity increased the amounts of the antioxidant catalase and peroxidase enzymes but ascorbic acid could increased the activity of them in saline condition.
Conclusion
It seems that application of ascorbic acid as an antioxidant could reduce the effects of salinity stress by increasing the activity of catalase and peroxidase enzymes, reducing sodium uptake and increasing the uptake of phosphorus, potassium, iron, zinc and copper. These could have positive effects on the growth parameters of bell pepper seedlings in salinity conditions. Generally, on based of obtained results, spraying 5 mM Ascorbic acid on bell pepper seedlings modified the resistance of them in salinity stress conditions.
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.
Growing vegetables
Z. Darabi; F. Ghanbari; J. 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.
Growing vegetables
N. Zeinali Pour; F. Aghebati
Abstract
Introduction
Portulaca oleraceae is used in many countries for a variety of purposes, including human nutrition and the conversion and pharmaceutical industries. The edible parts of Portulaca oleracea are the young organs, especially the brittle leaves and stems. Over time, this medicinal herb ...
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Introduction
Portulaca oleraceae is used in many countries for a variety of purposes, including human nutrition and the conversion and pharmaceutical industries. The edible parts of Portulaca oleracea are the young organs, especially the brittle leaves and stems. Over time, this medicinal herb has been forgotten. Drought, on the other hand, is a factor in the decline of crops and horticulture around the world. Given the vastness of arid and semi-arid regions in Iran and also the reduction of access to water resources, appropriate arrangements should be made for the optimal use of water in the agricultural sector. Changing the planting pattern and using useful and resistant alternative species such as drought-tolerant medicinal plants can enable the optimal use of limited water resources. GABA is an important non-protein amino acid that plays a positive role in increasing plant resistance to stress.
Materials and Methods
This experiment was carried out in 2020 as a factorial based on a completely randomized design with three replications in the vegetable research greenhouse of the Faculty of Agriculture, Shahid Bahonar University of Kerman. Experimental treatments included different levels of GABA (0, 20, and 40 mM). Treatment with different concentrations of GABA was done in two stages of 6 and 12 leaves of portulaca oleracea and foliar application and application of dehydration stress in three levels of control, medium and severe at irrigation intervals of 7, 14, and 21 days from 6 leaf stage of plants to the end.
Results and Discussion
According to the analysis of variance, the effect of GABA at different concentrations and dehydration stress on plant height was significant at the level of 5% probability. Based on the mean comparison test, the highest plant height was obtained in GABA treatment of 40 mM and irrigation intervals of 7 days (control), and the lowest of this trait was obtained in GABA zero treatment and irrigation intervals of 21 days (highest stress level). The results of analysis of variance showed that the effect of GABA at different concentrations and dehydration stress on vegetative yield was significant, the interaction between irrigation intervals and GABA was significant at 5% level. Based on the mean comparison test, the highest vegetative yield was obtained in GABA treatment of 40 mM and irrigation intervals of 7 days and the lowest in control treatment and irrigation intervals of 21 days. According to the results of the analysis of variance table, the effect of GABA at different concentrations and dehydration stress on the amount of malondialdehyde was significant at the level of 1% probability. Based on the means comparison test, the highest amount of this trait was obtained in the control treatment. Comparison of the mean of the data showed that the effect of GABA at different concentrations and dehydration stress caused a significant difference in the probability level of 1% in the proline content of the data. Based on the mean comparison test, the highest amount of proline was observed in GABA treatment of 40 mM and irrigation intervals of 21 days and the lowest amount was observed in control treatment and irrigation intervals of 7 days. As can be seen in the comparison table of means, the highest activity of superoxide dismutase enzyme was obtained in GABA treatment at 40 mM and irrigation intervals of 14 days and the lowest in control treatment and irrigation intervals was 7 days (Table 2). The results of this study showed that the effect of GABA at different concentrations and dehydration stress on the activity of catalase was significant at the level of 1% probability. As can be seen in the comparison table of means, the highest level of catalase activity was 40 mM in GABA treatment and 21 days irrigation intervals and the lowest in GABA treatment was 40 mM and irrigation intervals were 7 days.
Conclusion
The results of this study indicate that GABA is able to greatly alleviate the oxidative stress caused by dehydration in Portulaca oleracea. This effect is quite evident in oxidative parameters, especially the activity of antioxidant enzymes. The concentration of 40 mM GABA was the most effective treatment in mitigating the effects of irrigation. The results show that the use of GABA makes Portulaca oleracea tolerant to dehydration stress.
Medicinal Plants
L. Vojodi Mehrabani; Y. Anvari Gheshlagh; A. Motallebi Azar
Abstract
Introduction
NaCl Salinity is one of the major environmental stressors affecting agricultural production everywhere. Salinity impacts the plants by the osmotic stress, nutritional imbalance with plants cells and by reducing the nutrients absorption and reactive oxygen species over-generation, ...
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Introduction
NaCl Salinity is one of the major environmental stressors affecting agricultural production everywhere. Salinity impacts the plants by the osmotic stress, nutritional imbalance with plants cells and by reducing the nutrients absorption and reactive oxygen species over-generation, as well as by ionic competition for the absorption, translocation, distribution and ion toxicity inside plants. Under salinity stress, plants develop various physiological and biochemical mechanisms to overcome this conditions, like ion homeostasis and compartmentalization, ion uptake, biosynthesis of osmoprotectants, activation of antioxidant enzymeic (superoxide dismutase, catalase, ascorbate peroxidase and glutathione peroxidase) and nonenzymic compounds (proline) to overcome salinity stress. Optimum nutrition under stressful saline conditions is important to overcome the problem and to produce optimum yield. Pelargonium graveolens is a plant commonly used in food and pharmaceutical industries. Iran has favorable micro-climates for the Pelargonium graveolens, production, and since this plants is in common use with diverse industries, this experiments was conducted to study the effects of foliar spray with Se and nano Fe on growth and physiological traits Pelargonium graveolens under NaCl salinity depression
Materials and Methods
Two separate experiments were concluded to evaluate the effects of foliar application of selenium and nano-Iron (0, 1.5 and 3 mgL-1) on pelargonium under saline (0, 50 and 100 mM) conditions as factorial based on Completely Randomized Design. In the first experiment, the effects of magnetized Iron and in the second experiment, the effect of selenium were assayed on pelargonium growth and physiological traits (plant dry weight, enzymic activity, elemental content, essential oil percent and oil constituents) under salinity stress.
Results and Discussion
The results obtained from the first experiment showed that, the aerial parts dry weight, Na, Fe and H2O2 content, catalase activity and oil percent of Pelargonium graveolens were independently affected by the salinity and (1.5 and 3 mgL-1) Fe foliar treatment. At the first experiment the highest amount of K/Na ratio, flavonoid content, K content, malondialdehyde, proline and superoxide dismutase activity were influenced by salinity stress. The top amount amount of plant dry weight, Fe content, K/Na, Na and superoxide dismutase activity were recorded at control plants. The top amounts of Na, proline, malondialdehyde, H2O2 content were recorded at 100 mM salinity stress. control and 50 mM NaCl increased oil percent in plants. Foliar spray with 1.5 and 3 mgL-1 Fe increased catalase, yield, phenolic content and oil percent in plants. At the second experiment; aerial parts dry weight, proline and flavonoid content were influenced by salinity stress. Catalase activity, malondialdehyde, superoxide dismutase activity and H2O2 content were influenced by sole effects of salinity and Se foliar application. Under non saline condition, plant dry weight, superoxide dismutase activity, K content were increased in plant. With increasing salinity to 100 mM NaCl, proline, malondialdehyde and H2O2 content were increased. Se, Na content and K/Na ratio in the second experiment was influenced by the interaction effects of salinity and foliar spray. At the second experiment, the top amount of K/Na ratio were recorded at NaCl0 × 1.5 and 3 mgL-1 Se spray. The top amounts of Na were recorded at NaCl0 × no foliar application. The superoxide dismutase activity, malondialdehyde and K+ were responded to the individual effects of salinity and Se treatment. The highest amounts of total phenolic content was attained by (1.5 and 3 mgL-1) nano Fe and Se treatment in both experiment. With salinity of 50 and 100 mM, the flavonoids contend was increased at both experiments. Foliar spray with 1.5 and 3 mgL-1 Nano Fe and Se increased catalase activity in plants. 1.5 and 3 mgL-1 Se and nano Fe foliar application reduced H2O2 content in plant at both experiment. GC/MS analysis revealed that β-citronellol (12.5-20.5%) was the major constituent with control treatment Citronelly formate (10.75-25.2%) were the dominant constituents of oil control plants. Β-Thujone (12.61%), trans-Rose oxide (2.85- 9 %) and the highest amounts of Aromadendrene (5.42 %) only recorded at control plants. Salinity stress and foliar spray had negative effects on α-Pinene biosynthesis and the highest amounts of α-Pinene was recorded in control plants. The top amounts of Geranyl formate (0.7-7.8 %) was recorded at NaCl50 × 1.5 mgL-1 Fe spray. Y- muurolene (0.4 – 4.06 %) biosynthesis increased at NaCl50 × 1.5 mgL-1 Se.
Conclusion
Salinity stress involves changes in metabolic processes and various physiological traits, controlled by salinity stress severity. In total, salinity had negative effects on the growth and physiological responses of plants, however, foliar treatment with Se and Fe improved some physiological traits of Pelargonium graveolens.
Pomology
S. Azizifar; V. Abdossi; R. Gholami; M. Ghavami; A. Mohammadi Torkashvand
Abstract
Introduction: The availability of water for irrigating crops is one of the serious challenges at present and the future of the world. Drought stress has harmful effects on plant growth and productivity, though bringing some serious changes in plant physiology and biochemistry. Drought reduces plant growth ...
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Introduction: The availability of water for irrigating crops is one of the serious challenges at present and the future of the world. Drought stress has harmful effects on plant growth and productivity, though bringing some serious changes in plant physiology and biochemistry. Drought reduces plant growth and yield by having negative effects on plants water potential, cell division, photosynthesis activity, chlorophyll content, and protein synthesis. Although olive naturally tolerates drought, studies had shown that drought undermines its growth, yield and photosynthesis. Employing some appropriate transpiration-reducing approaches could induce olive tolerance towards water deficiency. In this regard, kaolin, through raising light reflection and diminishing the rate of transpiration, is able to lessen leaf temperature in the stressed plants. Salicylic acid (SA), as a strong signaling molecule in plants, regulates physiological and biochemical functions effective in defense mechanisms and also boosts biological and non-biological factors involved in augmenting plants.. The major roles of SA in drought- stressed plants are as follows: activation of antioxidant defense system, production of secondary metabolites, synthesis of osmolytes, optimization of mineral status and maintenance of proper balance between plant photosynthesis and growth. Although some information over effects of SA and kaolin individually on stressed plants is available, to the best of our knowledge, their simultaneous effects on plants under stressful conditions has not been investigated yet. Therefore, the present study was aimed to investigate different applications of SA and kaolin (i.e. individually and simultaneously) on field-grown olives under drought condition.Materials and Methods: This research was conducted in Dalahu Olive Research Station located in Kermanshah province. This experiment was designed as a factorial experiment in the form of a randomized complete block design with 3 replications. Factors included different foliar spraying (i.e. control, 1 mM SA, 2.5% kaolin, and a combination of them in the mentioned concentrations) and irrigation at three levels (i.e. 100, 75, and 50% of water requirement). Irrigation was performed based on three-day interval schedule according to the above method by measuring daily evapotranspiration and required volume of water by considering the plant coefficients of olives and by drip irrigation.Results and Discussion: Although olive tree is a drought-tolerant plant, drought diminished its yield. The results of this study demonstrated a decrease in total yield of olive trees due to water deficit in different years. In this regard, water deficit under high temperature and low atmospheric humidity are believed to bring about a reduction in yield of drought-stressed olive. The results of this research showed that the foliar application of SA and kaolin on olive trees led to a reduction in ionic leakage and malondialdehyde (MDA) and an increase in RWC, chlorophyll content, phenol and total yield, as compared to the control. Foliar application of SA caused a significant increase in proline content and total carbohydrates, while kaolin had no significant effect on aforementioned traits. It seems that a reduction in oxidative damage and an increase in yield of olive cultivars under different irrigations manifested several defense mechanisms induced by exogenous application of SA and kaolin. In this context, kaolin was found to protect leaves and fruits from harmful ultraviolet rays and this remarkably improves the performance of drought-stressed plants by a decrease in the ambient temperature of plants in order to mitigate deleterious effects of drought such as oxidative damage, chlorophyll degradation, and lowering RWC. These results have been substantiated for different olive cultivars at different parts of the world under this condition.In the present study, SA increased chlorophyll content, RWC, proline content, carbohydrate and total phenol; as a result, the yield of SA- treated plants was higher than that in control plants. Similarly, Brito et al (5) reported that applying SA on drought-stressed olive improved osmolate accumulation, photosynthesis activities, RWC and chlorophyll content. The accumulation of phenolic compounds in SA-treated plants is believed to protect plants against stressful conditions. Therefore, the role of SA and kaolin in alleviating drought in favor of enhancing plants yield represents their efficiency under such condition. In the present study, we also employed a combination of SA and kaolin and the results showed no synergistic function between them on most traits. Therefore, to reduce the effects of drought on olive tree, it is recommended to utilize SA or kaolin separately.
َA. Samadi; A. Hassani; M. Gholamhoseini
Abstract
Introduction: Plant growth promoting bacteria are beneficial microorganisms that produce plant resistance to a variety of biological and non-biological stresses, including drought, extreme temperatures, salinity, toxic metals, etc, and increase plant productivity and yield. The use of these microorganisms ...
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Introduction: Plant growth promoting bacteria are beneficial microorganisms that produce plant resistance to a variety of biological and non-biological stresses, including drought, extreme temperatures, salinity, toxic metals, etc, and increase plant productivity and yield. The use of these microorganisms as biological agents in increasing soil fertility and improving agricultural productivity has been studied by many researchers, so a proper understanding of their effect on drought resistance can be effective in water resources management. Useful in field and reducing environmental effects of using chemical fertilizers. The purpose of this study was to investigate the effect of some bio-fertilizers on growth and some physiological and biochemical characteristics of red radish and in comparison with potassium sulfate application under drought stress.
Material and Methods: In other to investigate the effect of application of bio-fertilizers containing potassium-soluble bacteria (Pseudomonas koreensis and Pseudomonas vancouverensis), phosphorus-solubilizing bacteria (Pseudomonas putida) and nitrogen-fixing bacteria (Pantoea agglomerans) on plant growth and function, this experiment was done with 10 treatments and three replications in the form of completely randomized design in greenhouse. Finally the statistical population consisted of 30 pots of 10 treatments and three replications for red radish. Drought stress was applied in such a way that the apparent symptoms of stress were seen in the plants and the amount of water used was the same for all plants. The experiment was carried out in greenhouses and nylon pots with a capacity of 6.5 kg were used. The soil was prepared using a calcareous soil of Zanjan University research field. Its absorption was less than critical. Organic matter content was 0.4% and lime equivalent was 14.1% pH of soil 7.57 and EC of abstract soil paste was 2.21. Pots were treated with municipal water for 25 days after planting. EC values of water was 400 µS / cm that irrigated the plants every three days. The desired bio-fertilizers were added to the pots with irrigation water. After 25 days, 15 pots of treatments 4 to 6 were subjected to drought stress. 40 days after planting before drying of the plants, weight, moisture content of plant tissue, leaf proline content, total free amino acid, and total soluble sugars in leaf extract were measured. Analysis of variance was performed using SAS software and LSD test at the 5% level was used to compare the means.
Results and Discussion: Results of analysis of variance showed that the effect of different treatments on aerial fresh weight was significant at 1% level. Fertilizer treatments under stress and non-stress conditions significantly increased aerial fresh weight. Among non-stress treatments, the highest fresh weight was obtained from treatment 2 (10.03 g / pot) and the lowest was in control treatment (6.55 g / pot). Among the drought stress treatments with application of different fertilizers used, treatment 8 (9.19 g / pot) had the highest and treatment 6 (7.04 g / pot) had the lowest fresh weight. Application of potassium sulfate fertilizer increased the fresh weight of aerial part both under stress and non-stress condition. Potassium soluble bio-fertilizer alone and in combination with other bio-fertilizers increased radish aerial fresh weight, which was not significantly different from potassium sulfate fertilizer. In radish, drought stress affected the tuber fresh weight more. The radish plant uses the water of the tuber reserve in drought stress so that the leaves are less susceptible to stress. In non-stress conditions, application of potassium sulfate fertilizer and bio-fertilizers in radish increased yield. Potassium sulfate effect was greater. In stress conditions, the effect of bio-fertilizers was more than potassium sulfate in stress condition. The effect of potassium soluble bio-fertilizer application was almost identical with the combined application of different biofertilizers. Drought stress increased the concentration of proline, amino acids and soluble sugars in leaves and tubers of radish. Increasing concentration of these compounds indicated that plants were resistant to drought. Application of potassium sulfate and bio-fertilizers decreased these concentration and the effect of bio-fertilizers was more than that of potassium sulfate. The amount of ion leakage also increased under drought stress but leakage decreased by using potassium sulfate and bio-fertilizers. Drought stress also reduced the starch concentration in leaves and tubers of radish, which is a consequence of drought stress.
Conclusion: In general, application of potassium sulfate and bio-fertilizers moderated the effects of drought stress and in some cases the effect of biofertilizers was greater. Integrated use of bio-fertilizers was not significantly different from the use of potassium soluble bio-fertilizer alone. So, the results of this study showed that the use of bio-fertilizers can be included in the plant nutrition program as a factor in reducing the negative effects of stress on plants.
S.M.B. Razavi nia; N. Pourghasemian; F. Najafi
Abstract
Introduction: Pollution of the biosphere with toxic levels of metals has accelerated dramatically since the beginning of the industrial revolution. Soil pollution by heavy metals including cadmium (Cd) and lead (Pb) is a global problem, which can cause agricultural lands to become hazardous for wildlife ...
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Introduction: Pollution of the biosphere with toxic levels of metals has accelerated dramatically since the beginning of the industrial revolution. Soil pollution by heavy metals including cadmium (Cd) and lead (Pb) is a global problem, which can cause agricultural lands to become hazardous for wildlife and human populations. Accumulated Cd and Pb in their roots and shoots may also be negatively affect their photosynthesis, growth, and reproduction. Cd and Pb uptake and their effects on plants may be influenced by a variety of factors, e.g. the plant species, cultivar, soil characteristics and etc. Heavy metals such as Cd and Pb may cause the formation of reactive oxygen species (ROS), damage plant tissue membranes, and inhibit photosynthesis, carbon dioxide assimilation, and growth. Photosynthesis is the fundamental process of energy metabolism and therefore, closely related to the plants growth and productivity. However, it is a sensitive process and an important target of environmental stresses. Plants counteract the harmful effects of heavy metals by a variety of protective mechanisms including immobilization, exclusion, chelation, compartmentalization, osmotic regulation and elevating antioxidant system.
Lemon balm (Melissa officinalis L.) is a widely grown aromatic and medicinal plant of the Labiatae family. The plant has various therapeutic properties and is also used to flavor different food products due to its particular taste. Little scientific data exist on the response of this medicinal plant to Cd and Pb stress. Therefore, the objective of this work was to investigate the biological and physiological responses of lemon balm (Melissa officinalis L.) under cadmium and lead stress conditions.
Materials and Methods: A factorial randomized complete block design experiment with four replications was used to study the effect of Cd in four concentrations (0, 6, 12 and 24 mg.kg-1 soil) as well as Pb in four concentrations (0, 150 300 and 450 mg. Kg-1 soil). Before harvesting, chlorophyll fluorescence, photosynthetic and transpiration rates were measured with fluorescence meter and photosynthetic meter, respectively. Thereafter, plants were harvested and the roots were washed in distilled water. Then, half of the plants were separated into roots and shoots, which were dried at 105 °C for 24 h to determine the dry weight, Cd and Pb concentrations, Cd transfer factor and essential oil content. The other half of the plants were separated into roots and shoots, kept in liquid nitrogen, and then stored in freezer for one week to determine proline and shoot MDA concentrations. Data were subjected to two-way analysis of variance (ANOVA) and the difference between means was compared using LSD test. A significance level of 95% was applied by SAS 9.2.
Results and Discussion: According to the results, root and shoot dry weight, protein content, photosynthetic rate, transpiration rate and chlorophyll fluorescence were decreased by increasing Cd and Pb concentrations. However, Cd concentration decreased these traits more than Pb. The shoot MDA concentration, essential oil and proline content were enhanced by increasing Cd and Pbconcentrations. The combination of two pollutants (Cd and Pb) together reduces the negative impact of each element alone. Shoot and root Cd and Pb concentrations were increased by increasing Cd and Pbconcentrations. The interaction effect of Cd×Pbapplication showed that increasing Cd concentration decreased root and shoot Pb concentrations and increasing Pb concentration decreased root and shoot Cd concentrations. Cd and Pb were not detected in essential oil. Moreover, the Cd transfer factor was increased with increasing Pb concentration under high Cd concentration levels (12 and 24 mg.kg-1).
Conclusion: This study demonstrated that Cd toxicity is more than Pb toxicity due to its high mobility. There was an antagonistic relationship between Cd and Pb. Furthermore, due to the absence of Cd and Pb in the essential oil, lemon balm may be a suitable plant for areas contaminated with heavy metals especial Cd and Pb.
F. Ghanbari; S. Akbari
Abstract
Introduction: Melon, like other members of cucurbitaceae family, is sensitive to cold stress. Applying different cultivation techniques in the nursery can provide some degree of tolerance to environmental stresses in the plants. In the other words, applying stress conditions on plants may cause them ...
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Introduction: Melon, like other members of cucurbitaceae family, is sensitive to cold stress. Applying different cultivation techniques in the nursery can provide some degree of tolerance to environmental stresses in the plants. In the other words, applying stress conditions on plants may cause them to withstand subsequent stresses, this is so called a cross-adaptation or cross-tolerance. For example, Whitaker (1994) showed that cold stress damage can be mitigated by temperature pretreatment. This technique was then used to improve stress tolerance in different plants. In this regard, heat treatment has been used to increase the chilling tolerance in fruits and vegetables. Therefore, in this study, the possibility of increasing cold stress tolerance in melon seedlings using heat shock was investigated. Materials and Methods: The experiment was conducted in a completely randomized design (CRD) with three replications and five treatments (including control and spraying with water at temperatures of 20, 45, 50 and 55 °C for 90 seconds) in Faculty of Agriculture of Ilam University in 2019. Heat treatments where used as foliar spray by heated water. After applying different levels of heat treatment and recovery at 24 hours, seedlings were exposed to chilling stress at 3 °C for 6 h in 6 consecutive days. All seedlings were transferred to greenhouse and after 72 hours, the related traits were measured. Results and Discussion: Results showed that pre-treated seedlings had higher growth rate than control seedlings at the end of chilling period. Heat shock pretreatment significantly increased the content of chlorophyll, proline and hydrogen peroxide and reduced the amount of malondialdehyde compared to the control. The lowest amount of malondialdehyde (1.14 nmol g-1 fresh weight) was observed in the 50 °C treatment, which was 50% lower than the control. Similar to other environmental stresses, low temperature usually leads ROS production and oxidative stress. Malondialdehyde content is an index to measure membrane lipid peroxidation and its measurement is a criterion of damage to plants in stress conditions. Reduction of malondialdehyde has been reported to increase cell membrane stability and increase stress tolerance in plants. In the present study, heat shock reduced the accumulation of malondialdehyde compared to the control, indicating a decrease in cold effects on the plant. Mei and Song (2010) investigated the effect of heat pretreatment on increasing high temperature tolerance in barley, and reported that using this method by stimulating the synthesis of antioxidant enzymes prevented the increase of malondialdehyde in the plant under heat stress. Therefore, maintaining the membrane structure and decreasing the accumulation of malondialdehyde in melon seedlings under cold conditions indicates an improvement of plant defense responses induced by heat shock. Environmental stresses including cold stress by producing hydrogen peroxide and other free radicals lead to oxidative stress and damage plant cells. Hydrogen peroxide is converted to water by ascorbate peroxidase, peroxide redoxin, glutathione peroxidase and guaiacol peroxidase groups. Therefore, increasing the activity of antioxidant enzymes in plants is one of the most important mechanisms of the plant to cope with stress conditions. In the present study, heat shock pretreatment significantly increased peroxidase (POD) and poly phenol oxidase (PPO) activity and increased the amount of proline and hydrogen peroxide. In this regard, it has been reported that hydrogen peroxide has a dual role in plants and its increase in stress conditions by regulating the production of antioxidant enzymes helps plants to enhance their tolerance to the stress conditions. Our results is in consistent with Ao et al. (2013) report that stated hardening pretreatment of Jatropha curcas seedlings caused to increase the antioxidant enzymes activity, plant glutathione and ascorbate content. The increases in antioxidant enzymes activity by heat shock might be a positive mechanism, which facilitate the scavenging of ROS and induce plant growth and development under chilling stress. These results indicate that antioxidant defense system has a specific role in enhancing plant tolerance to stress conditions and hydrogen peroxide play an important signaling role in plant adaptive responses. Conclusion: In general, the results showed that heat shock (especially at 50 and 55 oC) caused positive physiological changes in melon seedlings and could increase their tolerance to cold stress conditions.
H. Nastari Nasrabadi; S.F. Saber Ali
Abstract
Introduction: Melon (Cucumis melo L.) is one of the most important vegetables in Cucurbitaceae family and one of the most important economic crops in the Torbat-e Jam city (Longitude: 60 ̊48', latitude: 35 ̊31', altitude: 928 m). Growth and yield of agricultural crops are affected by biotic ...
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Introduction: Melon (Cucumis melo L.) is one of the most important vegetables in Cucurbitaceae family and one of the most important economic crops in the Torbat-e Jam city (Longitude: 60 ̊48', latitude: 35 ̊31', altitude: 928 m). Growth and yield of agricultural crops are affected by biotic and abiotic environmental stresses. Cold stress can be one of the most important environmental factors reducing crops yield. Cold acclimation in plant is a complex process involving many morphological, physiological and biochemical changes, including a significant reduction in tissue hydration during cold hardening. Melatonin (MEL, N-acetyl-5-methoxytryptamine) is a conserved substance, which has been discovered in all living organisms, from bacteria to mammals. MEL regulates the growth of root, shoot, and explant, activates seed germination and rhizogenesis, and delays leaf senescence. In addition, the most frequently mentioned functions of MEL are related to various abiotic stresses such as drought, radiation, low/high temperature, heavy metals, and salinity stresses. Materials and Methods: In order to investigate the effect of PEG priming and melatonin on cold stress resistance of melon seedlings, a factorial experiment was conducted in a completely randomized design with three replications in Torbat-e-Jam University. In this experiment polyethylene glycol 6000 was used to produce drought stress at three levels (0, 0.18 and 0.58 MPa) and melatonin was used at two levels (0 and 200 μmol). When melon seedlings were at 4 leaf stage, the amount of polyethylene glycol was added to the irrigation solution for a week and to prevent drought stress, drought stress was increased for 3 days and increased one third of the required concentration daily. Recovery was performed for three days after drought stress and during this period melatonin was added to the irrigation solution at the required concentration. Seedlings were then exposed to cold stress (T0: non-stress and T1: cold conditions). Control plants were kept in greenhouse conditions. Results and Discussion: Comparison of the mean results showed that there was an increasing trend in proline production by increasing drought stress. The highest amount of proline (0.80 µmol g-1 FW) was recorded at the highest level of drought pretreatment with no melatonin and without cold stress (D2M0T0), and then a decreasing trend in proline production was observed. The results showed that melatonin significantly increased leaf relative water content compared to the control. Interaction effects of drought pretreatment and temperature showed that there was a trend of decrease in relative water content by increasing drought pretreatment. Ghanbari and Sayyari (8) reported that drought pretreatment stress maintains relative water content of tomato seedlings under cold stress conditions. Drought pretreatment significantly reduced the amount of chlorophyll a and total chlorophyll. The results showed that the highest levels of drought pretreatment stress (D2) and melatonin (M1) maintained chlorophyll a under cold stress conditions. Results showed that the amount of chlorophyll b was decreased by drought pretreatment stress, but it increased by melatonin application in all compounds. Based on the results, it was found that only simple effects of treatments at 1% of probability level had significant effects on soluble sugars content. Comparison of the mean simple effects of drought pretreatment showed that under drought stress the amount of soluble sugars increased significantly and the highest sugar content was recorded at the highest drought stress level. The amount of soluble sugars in plants under cold stress also increased significantly. Melatonin application also significantly increased the amount of soluble sugars. Kabiri et al. (19) reported that the use of melatonin increased soluble sugars in Moldavian balm seedlings under osmotic stress which is similar to this study results. It was found that melatonin significantly increased phenolic compounds under stress conditions and significantly decreased electrolyte leakage.
H. Farhadi; M.M. Sharifani; M. Alizadeh; H. Hokmabadi; Sasan Aliniaeifard
Abstract
Introduction: Agriculture of Iran is known worldwide for its pistachio (Pistacia vera L.) and is one of the most important non-oil exports. Therefore, attempts to improve the yield can be one of the primary goals in the pistachio industry in Iran. Due to the drought problem in Iran, increasing the cultivation ...
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Introduction: Agriculture of Iran is known worldwide for its pistachio (Pistacia vera L.) and is one of the most important non-oil exports. Therefore, attempts to improve the yield can be one of the primary goals in the pistachio industry in Iran. Due to the drought problem in Iran, increasing the cultivation area to increase production may not be a good option. Therefore, the purpose of this study was to compare the drought tolerance of different pistachio seedlings from open pollination and pollinated with domestic species pollen and controlled crosses using integerrima pollen in order to find the most tolerant genotypes.
Materials and Methods:
The first step: Controlled pollination and hybrid seed production In order to produce hybrid seeds, a controlled pollination using integerrima pollen grains at Razavi Pistachio Research Institute was conducted for five cultivars; Ahmad Aghaei, Akbari, Sorkheh Hosseini, Garmeh and Fandoghi. Each replication had a tree and from each tree, seven branches were selected that had at least three to four flower buds and four branches from it for controlled pollination, two branches for open pollination and a branch was considered for negative control. Before the flower clusters were fully opened, 70% alcohol was sprayed on the branches to prevent the possibility of unwanted pollen. In order to ensure controlled pollination, in the bud swelling stage, the branches were isolated by double-layered bags measuring 30 × 45 cm. Pollen was collected from the Arzooieh area of Kerman province to select the male parent of integerrima. Then, a combination of flour and integerrima pollen (1:1 ratio) was injected into the insulating bags and pollination was performed. In late summer, hybrid seeds were harvested.
The second stage: Drought resistance test of hybrids obtained from first step The experiment was conducted as factorial based on a Completely Randomized Design with four replications at the research greenhouse located in Gorgan University of Agricultural Sciences and Natural Resources during 2019-2020. The treatments were consisted of ten pistachio genotypes; Ahmad Aghaei, Akbari, Sorkheh Hosseini, Garmeh, Fandoghi and (hybrids between integerrima as the pollinizer and genotypes of Ahmad Aghaie, Akbari, Sorkheh Hosseini, Garmeh and Fandoghi were applied as the maternal parent and three levels of drought including control (field capacity), mild stress (65% of field capacity) and severe stress (30% of field capacity) were applied on 3 months old seedlings for 84 days. Seeds obtained from free and controlled pollination were planted in pots with a diameter of 33 cm and a height of 35 cm on April 6, 2017. Three seeds were planted in each experimental unit, and after planting and ensuring establishment, the number of plants in the pot was reduced to the final level of one in each pot. Each replication was consisted of four experimental units or four pots, and each pot was contained a plant. At the end of the experiment, growth and physiological parameters were measured. Statistical analysis of the results was performed using SAS 9.1 software.
Results and Discussion: Results of statistical analysis showed drought stress had a significant effect on leaf number, stem length, root length, leaf relative water content, electrolyte leakage, chlorophyll a, chlorophyll b, total chlorophyll, carotenoid, and leaf and root proline content. With increasing drought levels, all traits except root length, electrolyte leakage and proline content were reduced in comparison with control. Sorkheh Hosseini × integerrima, Ahmad Aghaei × integerrima, Akbari × integerrima interactions and genotypes of fandoghi and fandoghi × integerrima interaction were superior in the most of traits by drought, respectively. Based on the results it seems hybrids of Sorkhe Hosseini × integerrima, Ahmad Aghaei × integerrima and Akbari× integerrima crosses will be used as genotypes with dry-tolerant genes to modify cultivars in arid regions.
H. Nastari Nasrabadi; S.F. Saberali
Abstract
Introduction: Melon (Cucumis melo L.) is one of the most important vegetables in Cucurbitaceae family and one of the most important economic crops in the Torbat-e Jam. Growth and yield of agricultural crops are affected by biotic and abiotic environmental stresses. Salinity stress can be one of the most ...
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Introduction: Melon (Cucumis melo L.) is one of the most important vegetables in Cucurbitaceae family and one of the most important economic crops in the Torbat-e Jam. Growth and yield of agricultural crops are affected by biotic and abiotic environmental stresses. Salinity stress can be one of the most important environmental factors limiting the yield of plants, especially in arid and semi-arid regions. It has been reported that by application of bio-fertilizers, root and shoot dry weight and nitrogen concentration in alfalfa increased under salt stress. Sarabi et al (44) in a study of different genotypes of melons under salinity stress reported that salinity stress increases soluble sugars and proline content and decreases photosynthetic pigments. Growth-promoting bacteria can help plants under stress conditions by stabilizing atmospheric nitrogen, increasing the accessibility of nutrients, and interfering by the production of plant hormones such as auxin, cytokinin, and gibberellins. Soliman et al. (49) also reported that growth-promoting bacteria increase the absorption of elements, especially nitrogen, in Acacia saligana. Basilio et al. (7) showed that growth-promoting bacteria increase plant height and yield of wheat. The use of salicylic acid to create plant reactions to environmental stresses has been suggested. Raghami et al (39) reported that salicylic acid improves vegetative indexes and photosynthetic pigments in eggplant under salt stress. It has been reported that salicylic acid treatment increased K in wheat under salt stress. Due to the expansion of saline soils as well as the reduction of fresh water resources, the purpose of this experiment is to better establish melon seedlings under adverse environmental conditions and to maintain and develop this valuable crop.
Materials and Methods: In order to study the effect of biological fertilizers and salicylic acid on physiological parameters and growth of Khatooni melon under salinity stress conditions, a factorial experiment was conducted based on completely randomized design with three replications in Torbat-e-Jam University. Salicylic acid treatment was selected at two levels, without (SA0) and one mM (SA1) salicylic acid. Bacteria treatments were including Azotobacter (B1), Azospirilium (B2), Azotobacter and Azospirilum (B3) and without inoculation (B0) and salinity treatments were prepared in five concentrations: control (S0), 50 (S1), 100 (S2), 150 (S3) and 200 (S4) mM of sodium chloride.
Results and Discussion: Interaction effects of salinity, salicylic acid and bacteria showed, proline content was increased by salinity stress. The highest of proline content was obtained by combination of 200 mM salinity, one mM of salicylic acid and Azetobacter + Azospirilum (S4 SA1 B3) and the minimum of it was recorded in contorol (S0 SA0 B0). Under salinity conditions, the accumulation of compatible solutions such as proline, glycine, betaine and other organic solutions in the plant occurs, which play an important role in protecting the plant against the harmful effects of stress. On the other hand, the increase in proline content by growth-promoting bacteria may be due to an increase in the absorption of nutrients, especially nitrogen, because proline has a nitrogenous structure.
Without salinity stress no significant difference observed between salicylic acid treatments on soluble sugars, but soluble sugars content were significantly increased by increasing salinity stress. The maximum and minimum of soluble sugars content were recorded in combination 200 mM salinity and one mM of salicylic acid (S4 SA1) and control (S0 SA0) respectively. Plants try to overcome salinity stress by producing organic compounds that are osmotically active such as soluble sugars.
It has been reported that the use of salicylic acid in eggplant and barley under salinity stress has increased the production of soluble sugars, which is consistent with the results of this study. In general, accumulation of proline and soluble sugars content might be due to increased synthesis and decreased degradation under stress conditions. According to the results, photosynthetic pigments and relative water content percentage (RWC %) were decreased under salinity stress. Simple effects of salicylic acid (SA1) and bacteria treatments especially combination of bacteria (B3) significantly improved Chlorophyll a, b, carotenoids and RWC. Sarabi et al. (43) reported that chlorophyll content, carotenoids and RWC were decreased in melon under salinity stress. Kheirizadeh Arough et al (29) reported that application of bio-fertilizers and nano zinc oxid increased content of chlorophyll a, chlorophyll b and carotenoids in Triticale under salinity conditions.
Conclusion: Based on the obtained results in this study, we can use Azotobacter and Azospirillum together for seed inoculation and spraying with salicylic acid for obtaining better growth and yield under salt stress.
F. Dezhabad; M. Haghighi
Abstract
Introduction: Most plants, especially those that are native to hot areas, show signs of injury when exposed to low temperatures. Damages caused by cold stress occurs at the cell and organs level, which reflects it at the plant surface. Color change, chlorosis, general reduction of growth, cellular tissue ...
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Introduction: Most plants, especially those that are native to hot areas, show signs of injury when exposed to low temperatures. Damages caused by cold stress occurs at the cell and organs level, which reflects it at the plant surface. Color change, chlorosis, general reduction of growth, cellular tissue destruction, non-absorption of nutrients, reduction of photosynthesis, non-transferring photosynthetic materials are from early effects of cold stress. Cellular responses to colds including loss of thoracic pressure, vacuolization, collapse of cytoplasmic membrane balance, cytoplasmic flow loss, and general organ dysfunction. The susceptibility of the plant to frost is different depending on the type of plant, variety, tissue morphology and other cellular characteristics, as well as the cold conditions of the period, time and cold intensity. In addition, it seems that organs of the plant have different degrees of cold tolerance. If the temperature of the aerial part is favorable, the low temperature of the root zone can be one of the factors limiting the root system and plant growth. The consumption of balanced boron content by neutralizing the negative effects of cold stress and mechanisms such as maintaining the structure of the membrane, improving and increasing root growth, increasing the synthesis of proteins needed for the plant, adjustment of stomatal movements and improved stomatal conductance, increased cell division, increased nitrogen metabolism and chlorophyll production, and its consequence was increased photosynthesis and dry matter production, increased activity of antioxidants, calcium / potassium ratio adjustment, optimizing the transfer of calcium in the plant, adjusting the amount of water and conducting it in the cell, increasing the moisture content and relative content of leaf water, transferring soluble materials and increasing water use efficiency creates a relative resistance to low temperature stress. Although the root temperature is very effective in plant growth, it has been less attractive. Therefore, the aim of this study was to investigate the effect of low temperature of root and shoot on the ability to restore plant growth and physiological activity in the presence and absence of boron.
Materials and Methods: In order to compare the impact of sudden low temperature stress of root and shoot on recovery of vegetative and physiological traits of tomato, a research was conducted in two separate experiments under controlled conditions in the greenhouse of Faculty of Agriculture, Isfahan University of Technology. Two experiments were factorial based on completely randomized design with 10 replications including two concentrations of boron (0, 0.5, 1 and 1.5 in ppm) and two temperature levels of shoot and root sections (10 degrees’ Celsius temperature, and 11 rootstock temperatures and 22 ° C optimum and control temperatures). Indicators included photosynthesis rate, respiration rate, stomatal carbon dioxide, stomatal conductance, chlorophyll fluorescence, chlorophyll index, water use efficiency, proline, antioxidant, phenol secretion from root and leaf extracts, leaf relative water content, soluble protein concentration, ion leakage, leaf water potential, root and shoot dry weights and starch content. Finally, the analysis of the results was done by statistical software statistic and comparing the meanings by LSD test at 5% level.
Result and discussion: The results showed that the highest amount of photosynthesis, root dry weight and dry weight of the aerial part were in the consumption of 0.5 ppm of boron during abrupt stresses of low temperature on the root after the recovery period. The highest amount of stem proline and electrolyte leakage were also obtained from 0.5-1.5 ppm of boron consumption during abrupt low temperature on the shoot part. According to the results, it was found that when stress has entered from the root zone to the aerial part of the plant, the plant was in the better conditions after the recovery period. It seems that when a cold stress occurred on the roots, the plant can produced more antioxidant substances, including phenol and proline, while counteracting the relative water content of the leaves were more effective with radical agents. Thus, in normal conditions, the roots of the plant operated at a lower temperature than the airspace. They also exhibited more adaptations to the lower air at the lower temperature than the air section and the plant is less damaged. At levels above the boron element due to the effect of boron toxicity and the production of excess free oxygen radicals, the plant probably suffered more severe damage than cold damage.
Conclusions: Sudden low temperatures stresses on the root and shoot had negative effects on the recovery of the vegetative and physiological traits of tomatoes. When lower temperatures were imposed on the shoot, the plant suffered much more damages. Consumption of 0.5 ppm of boron during cold stress by creating optimal conditions for growth also caused the relative neutralization.
Y. Selahvarzi; M. Kamali; J. Nabati; H. Ahmadpour Mir
Abstract
Introduction: Each year, with the onset of cold season and severe drop in temperature, the probability of frost bite and frost damage is a problem for landscaping plants. Many plant species, especially tropical and subtropical species, are damaged when exposed to frostbite, causing damage to ...
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Introduction: Each year, with the onset of cold season and severe drop in temperature, the probability of frost bite and frost damage is a problem for landscaping plants. Many plant species, especially tropical and subtropical species, are damaged when exposed to frostbite, causing damage to their cells, tissues, and organs. Research has shown that by altering membrane properties during cold stress, metabolic balance is disturbed and with the increase in toxic metabolites, secondary damage to the plant can occur. At low temperature, decreases the efficiency of energy transfer to the center of the photosystem II. In addition, low temperatures are the main cause of the formation of reactive oxygen radicals. Also, lowering the temperature in the presence of light, due to the imbalance between light absorption and photosynthesis, increases the risk of light oxidation. Low temperature also reduces the activity of Rubisco. The amount of free proline in many plants increases significantly in response to environmental stresses such as frost stress, and stabilizes the membrane during cold stress.On the other hand, the use of some organic materials such as organic mulches increase temperature of the soil, and thus helps plant from frostbite. Use of organic mulch is widespread in agriculture due to the positive effect in soil temperature, weed control and moisture retention. Also, these mulches are effective in height, growth and flowering, early maturity and total yield of the products. Mulches in the warm seasons reduces soil temperature. Use of mulch can also help plants to withstand frostbite. Organic mulch decomposition in appropriate temperature and humidity conditions, liberates the nutrients gradually and provides for root plant and microorganisms of the soil. Organic mulches can reduce the effect of salt toxicity on plant growth and actively increase soil desalination. The most important benefit of mulch is the increase in soil temperature in the seed area, which accelerates the growth and yield of the product. Use of straw as mulch resulted in accelerated germination in cucumber. Use of straw mulch leads to an increase in temperature at night, thus protecting plants from temperature stress that has a positive effect on the growth and development of wheat.
Material and methods: In order to investigate the effect of freezing stress and using different types of organic mulch for Aquilegia plant, this experiment was conducted as a factorial experiment based on completely randomized design with four replications at Faculty of Agriculture, Ferdowsi University of Mashhad. The experimental treatments included four types of mulch (control (without mulch), 50% soil + 50% manure, 50% soil + 50% leaf needle + 50% soil + 50% rice bran) and five levels of freezing temperature (0, -5, -10, -15 and 20). Characteristics such as percentage of electrolyte leakage, relative water content, chlorophyll index and total chlorophyll, leaves number, leaf area, plant dry weight and proline leaf content were considered.
Results and Discussion: The results showed with decrease of temperature from 0 to -20 °C, stem diameter, leaf area and leaf number in bran mulch treatment decreased by 42.6%, 73.4%, 21.2% respectively, also stem diameter, leaf area and leaf number in mulch of leaf needle were 35.2%, 9/64%, 47.6%, in manure mulch were 20.20%, 46.4%, 7.8% and in the control of mulch decreased, 32.8%, 79.7%, 30.7%, respectively. At -5 °C, the amount of proline was 26% in the leaf and at -20°C, the amount of proline increased 50% compared to the control. Also, the lowest proline (0.73 μmol / g fresh weight) was obtained from the plants that treated with bran mulch. With application of, electrolyte leakage reached 63.6%, 68%, 61% and 57% in control conditions bran, needle and manure, respectively. In short, the least electrolyte leakage was observed in manure. On the other hand, when temperature dropped from 0 to -20 °C, the percentage of electrolyte leakage increased in Aquilegia. Relative water content of the leaf were 24% at 0°C, 38% at -15 °C and 23% at -20 °C. In terms of non-use of mulch, the relative water content was 36% and reached a 42% and 40% with application of manure and needle using mulch. By measuring the total carbohydrate found in Aquilegia leaf, it was observed that the amount of this trait was increased under frost stress. In general, although frost stress reduced the morphological traits of Aquilegia, use of organic mulch resulted in the improvement of these traits. The best results were observed in manure mulch.
A. Safarzadeh; G. Barzin; D. Talei
Abstract
Introduction: The salinity affliction of land constitutes a major threat amongst the various forms of soil degradation. Arbuscular mycorrhiza fungus can be useful as a bio-fertilizer in providing plant nutrition and reducing the effects of environmental stresses on plants. On the other hand, nitric oxide ...
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Introduction: The salinity affliction of land constitutes a major threat amongst the various forms of soil degradation. Arbuscular mycorrhiza fungus can be useful as a bio-fertilizer in providing plant nutrition and reducing the effects of environmental stresses on plants. On the other hand, nitric oxide plays a role in many environmental and non-environmental stresses, including drought and salinity stresses. Liquorice (Glycyrrhiza globra Linn.), commonly known as Mulahatti and Yashtimadhu, is the highest priority value crop which can be successfully cultivated on salt-affected and degraded lands. It is a small perennial leguminous herb of the family Fabaceae (Papilionaceae) native to the Mediterranean region and central and southwest Asia, and cultivated in Italy, Russia, France, UK, USA, Germany, Spain, China, Pakistan, Afghanistan, Iran, Iraq, Uzbekistan, Turkey, Turkmenistan and north-western India. This research was carried out with the aim of investigating the effect of nitric oxide modification on coexistence with arbuscular mycorrhizal fungus on some of the physiological traits of licorice under the salt stress of sodium chloride.
Materials and Methods: This research was a factorial experiment based on completely randomized block design with three replications. Factors consisted of five levels of NaCl-salinity (0 as control, 50, 100, 150 and 200 mM), two levels of nitric oxide (0 and 0.2 mM) and two levels of mycorrhizal fungi (the presence and absence of mycorrhizal). To do this, 10 kg pot of pumice mixture and pumice (1 to 1 ratio) were poured into 60 plastic containers (30 x 20 cm; 10 L) and sterilized by alcohol. The seeds germinated in petri dishes after adequate growth, they were transferred to the pots (all seeds were germinated and grown in the same conditions). In each pot, five seedlings were cultured and irrigated with distilled water until a two-leaf stage. After that, the treatment was carried out by a Hoagland solution. Application of saline treatments and nitric oxide (from sodium nitroproced as nitric oxide source) was performed 45-days. Finally, after 60 days of planting, sampling was carried out to measure the physiological traits from the middle leaves of each pot, and after being placed in an aluminum foil with ice-containing flux, it was transferred to the laboratory and then transferred to 80 o C. The evaluated traits were leaf flavonoids by Swain (52) method, proline content by Bates et al. (6) method, MDA with Ohkawa et al. (40) method, CAT activity by Pereira et al. (44) method, POD activity by Korori (28) method and SOD activity by Giannopolitis and Reis (21) method. The data were analyzed by SPSS 22 (IBM SPSS Statistics 22.0) software application. The data was normalized and inferential statistics such as analysis of variance and mean comparison of treatments were calculated using Duncan's multiple range test.
Results and Discussion: The results showed that the salinity stress had significant effect on flavonoid content, proline content, malondialdehyde rate and antioxidant activity of catalase, peroxidase and superoxide dismutase. Salinity had increased levels of malondialdehyde, proline content, and the activity of antioxidant enzymes (catalase, peroxidase, and superoxide dismutase). The coexistence of mycorrhiza fungus in combination with nitric oxide or alone reduced the number of flavonoids and increased proline content at each level of salinity stress. Nitric oxide had no significant effect on measured traits but was more effective in combination with Mycorrhiza fungi. In general, sodium chloride salinity stress had a negative effect on the physiological traits of liquorice, but the use of nitric oxide with arbuscular mycorrhizal fungus reduced the negative effects of stress. In general, it can be said that the removal and decontamination of active oxygen species is an important part of salinity tolerance in plants. In the present study, salinity stresses have significantly increased the amount of MDA, which is an indicator of plant response to stress. In addition to salinity stress, nitric oxide stress has been induced to reduce the effects of high salt concentration on some of the indices, thus reducing nitric oxide in high concentrations of MDA. Application of saline treatment significantly increased the activity of the three antioxidant enzymes CAT, POD, and SOD. The results showed that salinity stress had a decreasing effect on studied traits, but the application of arbuscular mycorrhizal fungus with nitric oxide reduced the negative effects of sodium chloride salinity stress on liquorice plant.
Maryam Kaamali; Mahmoud Shour; Seyyed Hossein Neamati; A Lakziyan; Hamidreza Khazaie
Abstract
Introduction: Water deficiency is one of important abiotic stresses that severely effects on plant growth. The effects of drought range from morphological to molecular levels and are evident at all phenological stages of plant growth at whatever stage the water deficit takes place. Growth is accomplished ...
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Introduction: Water deficiency is one of important abiotic stresses that severely effects on plant growth. The effects of drought range from morphological to molecular levels and are evident at all phenological stages of plant growth at whatever stage the water deficit takes place. Growth is accomplished through cell division, cell enlargement and differentiation, and involves genetic, physiological, ecological and morphological events and their complex interactions. The quality and quantity of plant growth depend on these events, which are affected by water deficit. Cell growth is one of the most drought-sensitive physiological processes due to the reduction in turgor pressure. Under severe water deficiency, cell elongation of higher plants can be inhibited by interruption of water flow from the xylem to the surrounding elongating cells. Impaired mitosis, cell elongation and expansion result in reduced plant height, leaf area and crop growth under drought. Chlorophyll content is one of the major factors affecting photosynthetic capacity changing in chlorophyll content of plant under drought stress has been observed in different plant species and its intensity depends on stress rate and duration. Chlorophyll content of leaf is indicator of photosynthetic capability of plant tissues. In the mid-80s, RWC was introduced as a best criterion for plant water status which, afterwards was used instead of plant water potential as RWC referring to its relation with cell volume, accurately can indicate the balance between absorbed water by plant and consumed through transpiration.
Materials and Methods: To study the effects of drought stress on three varieties of petunia, a factorial experiment based on randomized complete block design with four replications was conducted. The treatments consisted of four irrigation levels ((100% control), 80%, 60% and 40% of field capacity) and three varieties of petunia (Supercascade, Tango blue and Tango white). After planting and transplanting and after full deployment in the pot, water stress treatments were applied on three varieties of petunias. At the end of each week fully blossomed flowers were counted, flower diameter, peduncle length and corolla length were measured. In order to determine the stability of the cell membrane electrolyte leakage index was measured. Specific leaf area (SLA) was determined. The amount of chlorophyll a, b, total and carotenoid and relative water content in the leaves were measured. Statistical analysis was performed using the software MSTAT-C. EXCEL was used for diagramming software. Means were compared using LSD test with a 0.05 significance level.
Results and Discussion: Results indicated that interaction impacts of variety and irrigation on dry weight, leaf area, flower number, flower diameter, length Corolla, chlorophyll content, electrolyte leakage, relative water content and proline content was significant. The most shoot dry weight (76/1 g) was in control stress (100% FC) and Tango White variety. Also the most leaf dry weight (07/2 g) and root dry weight (g 43/0) were in Tango Blue variety. With increasing drought stress from 100% FC to 40% FC, leaf area decreased in Supercascade from 314 to 49, in Tango Blue from 405 to 44 and in Tango White from 459 to 69 cm2. In 80% FC, electrolyte leakage increased in all varieties (Supercascade variety 2%, Tango Blue 10% and in Tango White 3%) compared to control. Also electrolyte leakage increased in Supercascade 17%, in Tango Blue 9% and in Tango White10% in 40% FC compared to control. Comparison of interaction effects of drought stress and variety also showed the most proline had accumulated in Tango White and drought 40% of field capacity and then in Tango Blue and stress 40% of field capacity. Generally two varieties of Tango Blue and Tango White in control irrigation had better growth and also in low irrigation were more resistant.
Shokrollah Hajivand; Mitra Rahmati
Abstract
Introduction: Nowadays, horticultural products especially in our country are damaged by the climate change events (rising temperatures, water shortage associated by drought and extreme temperature fluctuations). The greatest economic damage to horticultural crops are caused by winter chilling and / or ...
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Introduction: Nowadays, horticultural products especially in our country are damaged by the climate change events (rising temperatures, water shortage associated by drought and extreme temperature fluctuations). The greatest economic damage to horticultural crops are caused by winter chilling and / or spring frosts, in which has been increased by seventimes during the last 10 years. Indeed, just during 9 months of 2016-2017 year, the chilling/frost damages were reached to 140 million euro of the total damage value of 240 million euro to agriculture (about 60%). According to the Agricultural Insurance Fund, maximum amount of compensation to farmers of the country was paid to apples, walnuts, grapes, almonds, pomegranates, oranges and pistachios orchardists, respectively. Grape (Vitisvinifera), a member of the Vitaceae family, is the most important horticultural crop in Takestan region, ranking top in producing raisins in Iran. Yearly, horticultural practices in order to reduce the severity of chilling damages to crops cost a lot under orchard conditions. Some of these practices are included burying vines under soil, winter ice-watering, flood irrigation, and turning the heaters on. Nowadays, cheap and fast alternative methods such as anti-freezes spraying havebeen considered to reduce the freeze injuries under orchards. These compounds as mechanical barriers either prevent the ice crystals formation on the sensitive plant tissues or activate the freezing tolerance mechanisms in the plants. Salicylic acid (SA), a type of phenolic acid, is one of the most secondary metabolites in the grape. SA not only plays an important role on the determination of the quality, color and taste of fruit, but also influences on the plant responses into environmental stresses such as drought, chilling, salinity and heavy metals. Natural osmolites such as soluble sugars, amino-acids and ammonium compounds are accumulated inside the plants under natural conditions. Commercial anti-freeze/anti-transpiration compounds on the basis of the mentioned natural osmolites are used to increase the freezing tolerance or postponing the bud break of horticultural crops. For example, Bio-bloom, Tiofer®, Cropaid® and Fosnutren® were used as anti-freeze compounds under almond, cherry, pistachio and apple orchards in Iran. The efficiency of this method to reduce the chilling injuries in vineyards is not well known. Therefore, to consider the effects of plant basis anti-freeze compounds on the freezing tolerance of red seedless grape under Takestan climate conditions, the current experimentation was conducted. In this regard, the important freezing tolerance determining osmolites as well as some of the qualitative and quantitative characters of vines in response to these compounds were evaluated.
Materials and Methods: In order to study the likely increase in grape spring freezing tolerance using the anti-freeze compounds under the orchard, an experiment was conducted as randomized completeblock design (RCBD) with anti-freeze compounds in Agriculture and Natural Resources Research Center of Qazvin during 2012-2013. Minimum monthly temperature during the autumn and winter months was -12.2 °C. The treatments including the spray of SA, Tiofer®, Cropaid®, Bio-Bloom® and water (control) were used on vines during fourphonological stages: before plant dormancy, during bud swelling, start of clustering and during the final clustering on the three red seedless vines per plot. Quantitative and qualitative characters such as cluster weight, yield and total soluble solids (TSS) were measured. Leaves osmolites contents such as proline (Bates et al.,1973) and glycin-betain (Grieve and Grattan.,1983) as well as the status of the freezing resistance index enzymes activities such as Glutathione peroxidase (GPX) (Updhyaya et al.,), Ascorbateperoxidase (APX) (Nakano and Asada,1981) and Catalase (CAT) (Aebi, 1984) were evaluated. All statistical analyses were made using SAS software. The comparison of mean values for the different treatments was made by ANOVA, followed by the Duncan’s test at the significant level of 0.05.
Results and Discussion: The results showed that the anti-freeze compounds resulted in an significant increase in the TSS, cluster weight and yield by 22%, 17% and 26%, respectively and the most effectswas observed in Bio-bloom. Our results regarding the effect of SA on the TSS was in accordance with other researchers (ShokrollahFaam, 2011; Sedighi et al., 2011; Champa et al., 2014;Marzouk and Kasm, 2011). However the effect of other anti-freeze compounds on the quantitative characteristics has not studied yet. Tiofer and Cropaid had no significant effect on the grape cluster weight. Proline content increased significantly using anti-freeze compounds compared to control during 2012-2013. But there was no significant difference between the different anti-freeze compounds for proline content. The most important content of betaine-glysine was observed in SA and Bio-bloom treatments. A decrease in air temperature during 2013 dormancy period resulted in higher amount of osmolytes contents (betaine glycine) and freezing resistance index enzymes activities compared to those of 2012. The most important contents of these enzymes activities were obtained in SA, Tiofer, Cropaid and Bio-Bloom treatments, respectively and the less important content was observed in control.
Conclusions: According to these results the commercial anti-freeze compounds could be useful not only for an increase in the grape spring freeze resistance but also for an improvement in the grape cluster weight, total soluble solids and yield. Osmolytes contents such as such as proline and betaine glycine and enzymes GPX, APX, CAT are significantly higher in anti-freeze treated plants compared to control. Since high levels of soluble solids, mentioned osmolytes and enzymes resulted in an increase in cold resistance in plant, the use of antifreeze as an easy and inexpensive way to increase the cold hardiness of grapes is recommended. These results were obtained with this antifreeze in 5 ppm concentration. Therefore more researches on the other varieties using different concentrations of anti-freeze compounds are recommended.
