Research Article
Medicinal Plants
A. Balandari; M. Azizi; M. Khodabandeh
Abstract
Introduction
Barberries are small fruits with appealing colors and tastes, and have a great diversity in Iran. There are numerous indigenous barberry genotypes in Iran, which have remarkable therapeutical and nutritional attributes. Seedless barberry is the most famous genotype which fruits are ...
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Introduction
Barberries are small fruits with appealing colors and tastes, and have a great diversity in Iran. There are numerous indigenous barberry genotypes in Iran, which have remarkable therapeutical and nutritional attributes. Seedless barberry is the most famous genotype which fruits are rich in phytochemicals. Although Iran is one of the main habitats of the barberry species and hybrids and the seedless cultivar is considered as an exclusive crop for our country, a few products are being produced from such valuable crop in food industries.
Materials and Methods
In present study, fruit biochemical properties of the twelve barberry genotypes (including one seedless genotype and eleven seedy genotypes: 2-2, 4-1, 5-1, 5-2, 5-3, 8-3, 10-1, 11-1, 12-1, 13-1 and 14-2) of the barberry collection located in Research Institute of Food Science and Technology of Mashhad, were evaluated based on the fruit appearance. For this purpose, fruits were harvested in 2015 harvest time and divided into two parts. One part was dried in room temperature. Then dried fruits were kept in cool and dark place until analyses. The other part was kept fresh for some measurements including TSS, TA, TSS/TA and pH. Before all tests, fruits were deseeded and the properties of the pulp were determined. Biochemical properties included total soluble solid (TSS), titratable acidity (TA), TSS/TA ratio, fruit juice pH, total phenol content, total flavonoid content, total anthocyanin content, protein content, crude fiber, total sugar and minerals including Iron (Fe), Magnesium (Mg), Zinc (Zn) and Copper (Cu). Data analysis was performed based on completely randomized design by Minitab software version 16 using analysis of variance (ANOVA) and differences among means were determined for significance at p≤0.05 using Tukey’s range test.
Results and Discussion
Results showed significant variation in biochemical properties of genotypes. Based on the results, genotype code #13-1 had the highest content of titratable acidity (5.61 g malic acid per 100 g fresh fruit weight) and the highest soluble solids content (5.5 °Brix). The highest amount of crude fiber (54.96%), Fe (138.49 ppm), Mg (1426.39 ppm) was related to genotype code #10-1 and the highest amount of anthocyanin (452.60 mg/100g), protein (4.26%) and Cu (6.80 ppm) belonged to genotype code #14-2. Two genotypes “Bidaneh” and code #5-3 displayed a distinctive content of total carbohydrates with respectively 59.61% and 25.67%. Furthermore, genotype code #11-1 showed the highest amount of Zn (18.85 ppm) among all.
Conclusion
Up to now, barberry mostly has been consumed as a food seasoning and garnish. All data of this study suggest that barberry, as a functional food, can partially cover the body's daily requirements. Therefore, a comprehensive study should be performed to determine all the capacities and uses associated with each genotype. Overall, genotype code #14-2 can be introduced as the best genotype in terms of flavonoid, anthocyanin, protein and copper content of all the evaluated genotypes. Considering its high content of anthocyanin, producing an edible colorant powder is possible. In conclusion, considering the great diversity, fruits of indigenous barberry genotypes can provide a rich source of minerals and phytochemicals for food purposes. Furthermore, achieving applied science in making products from such indigenous crop could lead into investments and economic development in regions in which barberry is cultivated.
Research Article
Postharvest physiology
M. Kiaeshkevarian; T. Raiesi; B. Moradi; J. Fattahi Moghadam; M. Faghih Nasiri
Abstract
Introduction
Consumers demand for organic products is increasing due to their awareness of health and nutritional quality. Organic manures maintain soil health and ecological balance of the region. Organic agriculture, as an alternative agricultural system to protect human health and the environment ...
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Introduction
Consumers demand for organic products is increasing due to their awareness of health and nutritional quality. Organic manures maintain soil health and ecological balance of the region. Organic agriculture, as an alternative agricultural system to protect human health and the environment can improve the quality and storability of the product. Kiwifruit is one of the most important agricultural products in north of Iran, which plays an effective role in trade and employment of the people. Fertilization is one of the main factors affecting the yield and quality of kiwifruit. Growers use organic manures and chemical fertilizers in their orchard to achieve higher yields. It is necessary to study the effect of various organic manures available in the region on the nutrition of kiwifruit vines due to increase chemical fertilizer prices and the formation of the market for organic fruits. Therefore, the aim of this study was to compare the effect of using five types of organic manures and chemical fertilizer on the quality of Hayward kiwi fruit during cold storage.
Materials and Methods
This research was conducted as randomized complete block design consisting six treatments (including complete chemical fertilizer, sheep manure, cow manure, chicken manure, vermicompost and azolla) on Hayward kiwifruit vines in orchard and factorial experiment with three replicates in cold storage during four years. The fruits were harvested at TSS: 6.5 (approximately mid-November) and then stored at 0.5 ° C and 90% RH for three months. Sampling was performed every month and physicochemical characteristics, including flesh color parameters (L*, C*, h◦), total soluble solids, titratable acidity, firmness and weight loss of fruit were measured. Sensory evaluation of fruits was also performed at the end of three months cold storage. Analysis of variance of the data was done using SAS 9.1 software. The significance of differences between the mean of treatments was determined by using Duncan’s test.
Results and Discussion
The results showed the interaction between year, type of nutrition and cold storage period affected color indices, lightness and chroma. Lightness and chroma value didn’t show significant differences between organic and chemical fertilizer treatments. In addition, their value decreased during cold storage period, significantly. The chroma value indicates the degree of saturation of the green color and is associated with fruit firmness. The hue value was also influenced by the interaction between year and cold storage period and the simple effect of the nutrition type. The highest hue value was observed in chicken manure (108.63) and the lowest in vermicompost (107.66). The hue value decreased significantly after 90 days cold storage. According to the results, a decrease in fruit firmness, TA and an increase in TSS and TSS/TA were observed during cold storage irrespective of treatments. After 90 days, total soluble solids content was higher when organic fertilizers were applied. During the storage of kiwifruit, total soluble solids content increased, significantly. The titratable acidity value in organic fertilizer treatments was higher than chemical fertilizer after 90 days cold storage, significantly. Moreover, titratable acidity value decreased at the end of the cold storage period, significantly. The highest flesh fruit firmness was obtained in cow manure (8.74 kg/cm2) in forth year and chemical fertilizer treatment had the lowest flesh firmness (3.2 kg/cm2) in third year. Fruit lost firmness gradually during the cold storage period. However, no significant difference was found in maturity index (TSS/TA) between treatments. The TSS:TA ratio is highly increased after 90 days. Based on the results of the last two years, azolla, cow and chicken manures showed less weight loss percentage than chemical fertilizer treatment. Moreover, weight loss increased significantly during cold storage period in all treatments and years. Also the results of sensory analysis showed that fruits treated with vermicompost had a higher overall acceptance than other treatments.
Conclusion
Generally, organic nutrition plays an important role in increasing the nutritional value and shelf life of kiwifruit cv.Hayward. Organically produced fruits had higher firmness than conventionally grown fruits during storage. Application of cow manure and vermicompost showed favorable effects on important properties of kiwi fruit such as firmness, weight loss, TSS, TA and sensory quality. Therefore, organic fruits will have better quality in the cold storage. As a result, it seems that by reducing the use of chemical fertilizers in the current orchards, kiwi production will be close to the standards defined for organic fruit.
Research Article
Pomology
A. Fatemi; A. Safari; M. Saeidi; Z. Kolahchi
Abstract
Introduction
Drought is the most important limiting factor for the yield and quality of products in the world. Fertilizer application can mitigate drought stress in plants. Most farmers prefer to use inorganic (chemical) fertilizers because of their fast impact on plant growth. The reasonable ...
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Introduction
Drought is the most important limiting factor for the yield and quality of products in the world. Fertilizer application can mitigate drought stress in plants. Most farmers prefer to use inorganic (chemical) fertilizers because of their fast impact on plant growth. The reasonable cost of inorganic fertilizers and their availability are the other reasons. However, the long-term effects of organic fertilizers on plant growth and soil fertility has been proved. The grapevines are one of the most important garden products in the world as well as in Iran. It has been reported that the application of biochar has significant effects on soil fertility as well as plant growth. Biochars have properties such as highly porous structure, high specific surface area, higher water holding capacity of the soil, the long-term stability in the soil. In addition, our previous study indicated that it could decrease the hazard of sodium in soil compared with compost. In Iran, the cultivation area of grapevines was the second grade after the pistachio cultivation area in 2019. According to statistical data on agriculture in 2019, the cultivation area of irrigated and rain-fed grapevines in Kermanshah province was 7710 and 1515 ha, respectively. According to this report, the production of irrigated and rain-fed grapevines in Kermanshah province in 2019 was 82718 and 1763 tons, respectively. The effect of application of some inorganic and organic fertilizers under drought stress on yield, water use efficiency, and some biochemical characteristics of the grapevine leaves cultivar Bidane-Ghermez has been previously studied. In this research, the effect of drought stress and the application of potassium sulfate, compost, and biochar on antioxidant activities of the grapevine leaves cultivar Bidane-Ghermez was investigated.
Materials and Methods
A greenhouse study with a factorial experiment based on a block of randomized completely design was conducted with fertilizer treatments including control, potassium sulfate (1250 mg kg-1), compost (5% w/w), and biochar (10% w/w) without and with drought stress conditions (80 and 40% FC, respectively) during 2017-2018. For this research, the biochar was produced from apple tree pruning under low oxygen conditions by slow pyrolysis at 400 ◦C. The compost was purchased from the municipal compost factory of Kermanshah province. To evaluate drought stress and inorganic and organic fertilizers' application on antioxidant enzymes activities, the superoxide dismutase and peroxidase activities and total soluble protein of grapevine leaves were determined. The data were analyzed by ANOVA and the mean of studied characteristics was compared by Duncan’s test at 5% probability level using SAS software.
Results and Discussion
the results indicated that the interaction effect of fertilizers treatments and drought stress on the superoxide dismutase and peroxidase activities as well as total soluble protein was significant (P<0.01). Under drought stress conditions, among fertilizers’ treatments, the activity of superoxide dismutase for potassium sulfate was significantly lower than compost and biochar treatments (P<0.01). The results also showed that the peroxidase activity for compost was significantly higher than potassium sulfate and biochar treatments (P<0.01). Besides, the highest total soluble protein amount was found for biochar treatment (P<0.01).
Conclusion
according to the results of this study, it can be concluded that the increase of total soluble protein of grapevine leaves under drought stress conditions by biochar application contributed to the increase of superoxide dismutase and peroxidase activities also increasing the bioavailability of macro-and micronutrients. Biochar application increased significantly the potassium concentration of the leaves of the grapevines. Potassium regulates water movement at the plant and also provides a higher relative water content of grapevine leaves. Moreover, potassium decreases the non-stomatal effects are also attributed to stomatal closure during drought stress conditions. Furthermore, potassium contributes to protein synthesis. Biochar application also increased the phosphorus, copper, and magnesium of the leaves of the grapevine. Higher concentration of phosphorus under drought stress conditions caused the grapevine leaves to suffer less from phosphorus deficiency. Copper exists in superoxide dismutase and is considered a key player in superoxide detoxification. Under drought stress conditions, higher manganese concentration by biochar application resulted in more protection of the cellular membrane against Reactive Oxygen Species (ROS). For fertilizer recommendation in order to reduce drought stress effects on some antioxidant enzymes activities of Bidane-Ghermez grapevine leaves, the application of biochar is recommended first then potassium sulfate and compost.
Research Article
Postharvest physiology
M.R. Zandi; A.H. Aboutalebi Jahromi; B. Behroznam; A. Zakerin
Abstract
Introduction
Strawberry is one of the most important small fruits in the world, which is cultivated as a perennial plant in temperate regions of the world. Ripe strawberry fruit contains compounds such as protein, fiber, sugars such as fructose, glucose, sucrose, organic acids, vitamins, minerals, ...
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Introduction
Strawberry is one of the most important small fruits in the world, which is cultivated as a perennial plant in temperate regions of the world. Ripe strawberry fruit contains compounds such as protein, fiber, sugars such as fructose, glucose, sucrose, organic acids, vitamins, minerals, as well as phenolic compounds and anthocyanins. The aim of this study was to investigate some hormonal treatments and magnetic field on some physiological and biochemical characteristics, shelf life and postharvest life of strawberry cv. Selva under temperature stress.
Materials and Methods
This experiment was performed as a split plot based on a completely randomized design with 3 replications. Physiological and biochemical characteristics were studied on several tissues of Selva strawberry cultivar under several different temperature treatments. The treatments were gibberellic acid at three levels of control, 50 and 100mg/l in the main plots, magnetic field at 3 levels of control, 10 and 20ms, in the subplots and temperature stress in three levels including 2, 8 and 20°C. It was done on strawberries in subplots. Healthy prepared strawberry fruits were subjected to magnetic treatments and then immersed in hormonal solutions for 2min and after drying, stored for 8 days in different refrigerators at temperatures according to research treatments. The samples were then removed from the refrigerator and transferred to a laboratory to measure various characteristics. The studied traits included: fruit weight, fruit diameter, fruit length, fruit moisture content, titratable acidity, fruit juice pH and vitamin C.
Results and Discussion
Results of analysis of variance showed that the simple and triple interactions of treatments on all studied traits were significant. Comparison of the mean triple interaction of gibberellic acid treatment × magnetic field × temperature showed that the highest amount of fruit weight (19.49g), the highest amount of fruit diameter (33.7mm), the highest fruit length (48.62mm), the highest fruit moisture (34.65%) was obtained in the treatment of 50mg/l gibberellic acid, ten Tesla magnetic field and a temperature of eight degrees Celsius. The lowest fruit weight of 10.65 g was obtained in the treatment of non-use of gibberellic acid, non-use of magnetic field and temperature of 20°C. The lowest fruit weight loss of 3.74% was obtained in the treatment of 50 mg/l gibberellic acid, 20 Tesla magnetic field and 2°C. The lowest fruit diameter of 21.52mm was obtained in the treatment of non-consumption of gibberellic acid, absence of magnetic field and temperature of 20°C. The lowest fruit length of 25.63 mm was obtained in the treatment of no gibberellic acid, no magnetic field and a temperature of 20°C. The lowest amount of titratable acidity (0.31%), the lowest pH of fruit juice (4.68) and the highest amount of vitamin C (34.92mg/100 ml) in the treatment of non-use of gibberellic acid, no use of field Magnetic and a temperature of 20°C were obtained. The lowest amount of vitamin C was equal to 20.5mg/100ml in the treatment of no use of gibberellic acid, no use of magnetic field and a temperature of 20°C.High concentrations of gibberellic acid have a beneficial effect on increasing cell division and fruit size. Gibberellic acid increases fruit size and weight due to its effect on increasing cell division in the early stages of fruit development and increasing cell size at late fruit ripening. Magnetic field also affects plant metabolic activity. Fruit volume includes fruit length. It decreases due to the magnetic field. Fruit weight showed a significant positive correlation with fruit diameter, fruit length, fruit moisture and vitamin C. In terms of the triple interaction of the research treatments, the best effective treatment for increasing the storage time of strawberries was the combined treatment of 50 mg/l gibberellic acid and ten Tesla magnetic field and a temperature of 8°C.
Conclusion
Fruit weight showed a significant positive correlation with fruit diameter, fruit height, fruit moisture and vitamin C. In terms of the triple interaction of the research treatments, the best effective treatment for increasing the storage time of strawberries was the combined treatment of 50 mg/l gibberellic acid and ten Tesla magnetic field at a temperature of 8°C.
Research Article
Pomology
M. Fattahi; A. Mohammadkhani
Abstract
Introduction
UCB-1 hybrid rootstock is propagated from the seed of a controlled cross between a P. atlantica female and a P. integerrima male. Clonal propagation of this rootstock is also necessary since it produces identical genotypes. UCB1 has recently been introduced in Iran. However, little ...
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Introduction
UCB-1 hybrid rootstock is propagated from the seed of a controlled cross between a P. atlantica female and a P. integerrima male. Clonal propagation of this rootstock is also necessary since it produces identical genotypes. UCB1 has recently been introduced in Iran. However, little research has been done on this subject. Water stress is one of the most important environmental stresses and occurs for several reasons, including low rainfall, high and low temperatures, salinity, and high intensity of light, among others. Drought stress is a multidimensional stress and causes changes in the physiological, morphological, biochemical, and molecular traits in plants. Proline is also found widely in plants and accumulates in large quantities in response to environmental stresses such as drought. It is the essential amino acids that accumulate in different tissues of the plant, especially in the leaves through the effect of water stress, and that the accumulation of it has a function in the regulation of osmosis in the cell as the proline is increased in the cytoplasm to counterbalance effort osmosis cell sap. Proline is an indicator of water stress tolerance and its increase in the leaf proof that the plant suffered drought stress, also is the way the plant tolerance to drought stress.
Materials and Methods
A pot experiment was conducted, to investigate the effectiveness of foliar applied proline in mitigating the concurrent effects of drought stresses on UCB1 rootstock, at greenhouse of Faculty of Agriculture, University of Shahrekord. Experiment was carried out in a completely randomized design with split arrangement having three replications. Chl. and carotenoid contents were determined according to Lichtenthaler (1987). Leaf discs were obtained from expanded leaves of each pot in the morning. The leaf discs were weighed immediately to obtain the fresh weight (FW), and submerged in distilled water for 4 h at 4◦C in dark condition and then weighed to prepare turgor weight (TW). The leaves were dried in a forced-air oven at 70◦C for 24 h, and the dry weight (DW) was recorded. The RWC of samples was calculated using the following equation (Bastam et al., 2012): RWC = [(FW–DW)/(TW–DW)] × 100
Levels of glycine betaine were quantified as described previously by Arakawa et al. (1990). To determine the free-proline concentration, leaves were homogenized in 5 ml of ethanol at 95%. Proline concentration was calculated with a standard curve and expressed as µg g−1fresh mass (Paquin and Lechasseur, 1979).
Results and Discussion
The UCB1 proximate analysis in the present study depicted that imposition of drought stress increased the leaf and root proline content and electrolyte leakage. Exogenous application of proline as foliar spray significantly increased the moisture content of leaf and root, RWC, Chl a and total chlorophyll. Exogenous proline application upregulated leaf and root proline contents and decreased the lipid peroxidation (decrease electrolyte leakage), resulting into improvement in chlorophyll contents. 150 mg. l-1 proline application gave maximum alleviation against stress.
Numerous reports depict that the exogenous application of proline as a foliar spray can play an important role in enhancing plant tolerance against drought stress, and our results are consistent with them. This ameliorating effect of exogenously applied proline can take the form of osmoprotection, cryoprotection, or protection against reactive oxygen species.For example, in various plant species growing under stress conditions, exogenously supplied proline provided osmoprotection and facilitated plant growth. Normally, proline accumulation in plants, is in response to drought or salinity stress occurs in the cytosol where it contributes substantially to the cytoplasmic osmotic adjustment. It actively takes part in plant osmotic adjustment under stressful environmental conditions. In addition to its role as an osmolyte for osmotic adjustment, it actively takes part to stabilize subcellular structures, biological membranes, proteins, and scavenge free radicals. It also plays a vital role in buffering cellular redox potential under stressful environmental conditions.
Conclusion
In summary, our results showed that, drought induces a decrease in moisture content, RWC, T Chl and carotenoids and an increase in some osmoregulators (proline, glycine betaine, TSC). The most favorable treatment was 150 mg.l-1 proline foliar spray. 150 mg.l-1 proline application gave maximum alleviation against stress. Foliar application increased the moisture content of leaf and root, as well as increased the Chl a, total, RWC and proline content of leaf and root. It can be suggested that the foliar application of proline (150 mg L-1) used as a plants defense factor against drought stress conditions.
Research Article
Growing vegetables
J. Hamzei; M. Khishvand
Abstract
Introduction
Due to the limits of the conventional agricultural system, intercropping is important in terms of production sustainability. Intercropping plays an important role in increasing production and performance stability to improve the use of resources and environmental factors. Spinach ...
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Introduction
Due to the limits of the conventional agricultural system, intercropping is important in terms of production sustainability. Intercropping plays an important role in increasing production and performance stability to improve the use of resources and environmental factors. Spinach (Spinacia oleracea L.) is an important leafy vegetable, of which the leaves and tender shoots are consumed fresh or processed. Spinach is native to Iran. Spinach contains different flavonoids that function as antioxidants and anticancer agents. Also, spinach may be used in the prevention of Alzheimer's disease. It is an annual plant and as well as chickpea, spinach is grown as both an early spring and late fall crop in order to have growth at the coolest parts of the season. Spinach seed yield varies based on the climatic conditions, optimum sowing date and chose of the best planting pattern. Considering that the intercropping of this plant has not been studied with legumes such as chickpe, this experiment was designed to determine the possibility of intercropping spinach with chickpea using agronomical and economical indices, as well as determining the best planting pattern.
Materials and Methods
In order to investigate agronomic traits, yield and economical indices in spinach intercropping with chickpea, an experiment was carried out as a randomized complete block design with four treatments and three replications in 2017-18 growing season in Tuyserkan city, Hamedan province. In this city, spinach is mainly cultivated for seed production. Experimental treatments included additive intercropping of 20% chickpea with spinach, replacement intercropping of 60% spinach + 40% chickpea and pure stand of spinach and chickpea. Plant height, number of branches per plant, number of seeds per plant, 1000 seed weight, grain yield and biological yield in spinach, as well as plant height, number of branches per plant, number of pods per plant, number of seeds per pod, 1000 seed weight, grain yield and biological yield in chickpea were measured. To compare the advantages of intercropping of spinach with chickpea, the land equivalent ratio (LER), dry matter equivalent ratio (DMER), system productivity index (SPI), competitive ratio (CR), aggressivity (AG), actual yield loss (AYL ), relative value total (RVT), monetary advantage index (MAI) and intercropping advantage (IA) were calculated and evaluated. SAS 9.1 software were used for analysis of variance (ANOVA) calculations. The difference between the means was evaluated by the least significant difference (LSD) method at the level of 5% probability.
Results and Discussion
Plant height, number of branches per plant, 1000 grain weight and grain and biological yields of spinach were significantly affected by intercropping. The highest plant height and the lowest number of branches per spinach plant were obtained from the replacement intercropping. Additive intercropping and pure stand of spinach without significant difference had the lowest plant height and the highest number of branches per plant. The highest 1000 grain weight and grain yield of spinach were associated with the additive intercropping method. However, in terms of biological yield, the pure stand of spinach showed the highest results. Notably, there were no significant differences between the treatments of additive intercropping and pure stand of spinach concerning grain and biological yield of spinach. On the other hand, in chickpeas plants, intercropping had a notable impact on various parameters. Specifically, plant height, number of branches per plant, number of pods per plant, 1000 grain weight, and both grain and biological yields were affected by the intercropping method. Among these, the additive intercropping treatment resulted in the highest plant height, while it had the lowest number of branches and number of pods per chickpeas plant.The highest 1000 grain weight and grain yield of spinach were related to the additive intercropping. Pure stand of spinach had the maximum biological yield. Treatments of additive intercropping and pure stand of spinach were not significantly different in terms of grain and biological yield of spinach. In chickpeas plant, plant height, number of branches per plant, number of pods per plant, 1000 grain weight, grain and biological yields were affected by intercropping. The highest plant height and the lowest number of branches and number of pods per chickpeas plant were obtained at the treatment of additive intercropping. Maximum grain and biological yields of chickpea were belonged to the pure stand of chickpea. Spinach and chickpea were dominant and recessive plants, respectively. Evaluation of the economical indices also showed the advantages of spinach intercropping with chickpea at both intercropping design (replacemet and additive intercropping). So that the highest values for land equivalent ratio, dry matter equivalent ratio, system productivity index, actual yield loss, relative value total and monetary advantage index were achieved at additive intercropping system. But, the lowest values for these indices (1.13, 1.06, 1.20 and 1321 for LER, DMER, RVT and MAI, respectively) were revealed at replacement intercropping.
Conclusion
Overall, the results indicate that chickpea is a suitable plant for intercropping with spinach. So that the intercropping of 20% chickpea with spinach improved the yield performance of spinach and land-use efficiency and can lead to the greatest economical profit.
Research Article
Medicinal Plants
M. Amani; M. Sabzi-Nojadeh; S. Alizadeh-Salteh; M. Younessi Hamzekhanlu; B. Farmani; H. Hatef Heris; Sh. Mohammadian; S. Piretarighat
Abstract
Introduction
Medicinal plants have long had a special role in the traditional agricultural system of Iran and the use of these plants as medicine to prevent and treat diseases has been considered by traditional medicine experts since ancient times. Medicinal plants with rich sources ...
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Introduction
Medicinal plants have long had a special role in the traditional agricultural system of Iran and the use of these plants as medicine to prevent and treat diseases has been considered by traditional medicine experts since ancient times. Medicinal plants with rich sources of secondary metabolites provide the basic active ingredients of many medicines. Although the biosynthesis of secondary metabolites is genetically controlled, but their construction is strongly influenced by environmental factors. One of the important climatic factors that affect the distribution of plants around the world and can cause morphological, physiological and biochemical changes in the plant is the lack of available water. Basil seems to show little resistance to water stress. For this reason, there is a need for protective mechanisms for the basil plant against stress due to water shortage. Plants are able to reduce or eliminate the effects of water shortage stress by coexisting with a number of soil microorganisms. Inoculation of the plants with Arbuscular mycorrhizal fungi (AMF) has been exploited as an applicable strategy for reducing detrimental effects of water deficit stress. Present study was performed to evaluate the effects of three AMF on some physiological responses of Ocimum basilicum under water deficit stress.
Materials and Methods
The pot experiments were conducted as factorial based on completely randomized design blocks with three replications. The experimental factors were three AMF namely Glomus etunicatum, Glomus mosseae and Glomus intraradices and various soil moisture including severe stress, moderate stress, mild stress. Water stress was applied from the beginning to the end of flowering stage. After flowering stage, plants were harvested and traits such as total phenols and flavonoids, antioxidant capacity (DPPH), malondialdehyde (MDA), catalase and peroxidase enzymes were measured. To analyze the data, first the test of data normality and uniformity of variance within the treatment was performed and confirmed. The mean of treatments was compared by Duncan test at the level of 5% probability. SAS software (Ver. 9.3) was used to analyze the data and Excel software was used to draw the graphs.
Results and Discussion
The results of analysis of variance of the effect of mycorrhiza fungus and soil moisture on the studied parameters show that the effect of different levels of soil moisture on all traits was significant. The results of analysis of variance also showed that the effect of mycorrhiza on phenol and total flavonoids, antioxidant activity, catalase and peroxidase and malondialdehyde was significant at the level of one percent probability. According to the results of analysis of variance, the interaction effect of mycorrhiza on soil moisture on antioxidant activity was significant at 5% probability level and on total phenols and flavonoids, malondialdehyde, catalase and peroxidase at 1% probability level. Results showed that AMFs improve activity of catalase and peroxidase, antioxidant capacity and total phenols which led to decrease malondialdehyde content. Antioxidants as physiologically active compounds play an important role in plant resistance to stress. Increased oxygen species due to dehydration stress are a warning sign for plants and increase the activity of antioxidant enzymes. The plant's defense system increases the production of antioxidant enzymes to neutralize toxic oxygen forms, and fungi improve the intensity of this increase, which may be due to the chemical structure of the metal isoenzymes copper, zinc, and manganese. Factors sent to make antioxidant enzymes also contain the elements zinc and calcium. Mycorrhizal fungi increase the absorption of nutrients by sending more hormonal factors and increasing the activity of enzymes, all of which can be effective in increasing the activity of antioxidant enzymes.
Conclusion
When plants are exposed to dehydration stress, reactive oxygen species in them increase. The expression of antioxidant genes and the activity of antioxidants to eliminate reactive oxygen species are increased and the antioxidant defense system is improved and the tolerance to dehydration stress in the plant is increased. Scientists believe that peroxidase is involved in metabolic processes such as hormone catabolism, defense against pathogens, phenol oxidation, binding to cell structural proteins and cell wall polysaccharides. Present study revealed that application of AMFs can be good strategy for reducing harmful effects of water deficit stress in plants. Research has also shown that impregnating seeds with mycorrhiza increases antioxidants and reduces the amount of reactive oxygen species, a characteristic of resistance induction that occurs by this antagonist.
Research Article
Medicinal Plants
H. Gholami; M.J. Saharkhiz; M. Shirdel; K. Sartavi; H. Mazareie
Abstract
Introduction
Lavandula stricta, Cassia obovata, Cocculus pendulus, and Solanum xanthocarpum are among the species that can be grown in Bushehr province, and so far, there is no report describing the ecophysiological, herbicidal and biochemical characteristics of these species in Iran. In recent ...
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Introduction
Lavandula stricta, Cassia obovata, Cocculus pendulus, and Solanum xanthocarpum are among the species that can be grown in Bushehr province, and so far, there is no report describing the ecophysiological, herbicidal and biochemical characteristics of these species in Iran. In recent decades, many chemical herbicides have been used to control weeds in agricultural ecosystems. Despite the many benefits of these herbicides, their improper use has caused devastating effects on the environment and agricultural production and ultimately has harmed human health. At present, the approach of developed countries is to use non-chemical methods and natural materials (biocides) to control weeds. Bushehr province with an area of about 252,653 Km2 in southern Iran and the Persian Gulf and at an altitude of 0 to195 meters above sea level. The average rainfall in Bushehr province is 250 mm. Bushehr province has a great variety in terms of having medicinal plants that allopathic substances and secondary metabolites of these plants have received less attention. Therefore, the identification of secondary metabolites and plants with allopathic properties is very important for the production of biological herbicides.
Materials and Methods
This study was conducted to evaluate the eco-physiological, biochemical and herbicidal characteristics of Lavandula stricta, Cassia obovata, Cocculus pendulus and Solanum xanthocarpum. The plants were collected in April and May 2019. The location was situated in Kangan and Dashti, Bushehr Province, Iran. The ecological characteristics of the four areas such as latitude and longitude (UTM) and altitude were also recorded. Also, in order to determine the physicochemical properties of the soil in the collection areas of the studied plants, samples were taken from 15 different points of plant growth, from a depth of 0-30 cm and their properties were reported. In order to investigate the phytotoxic activity of the studied plants on germination and growth characteristics of Malva sylvestris and Chenopodium album in laboratory conditions, the seeds were first disinfected in 5% sodium hypochlorite for 5 minutes. Then the seeds were washed for 15 minutes and then dried at room temperature. In this study, Solanum xanthocarpum juice and alcoholic extracts of Lavandula stricta, Cassia obovata and Cocculus pendulus were used to investigate the phytotoxic properties and biochemical traits. From the extracts, concentrations of 0 (distilled water), 200, 400, 600, 800 and 1000 µl.L-1 were prepared and added to Petri dishes containing 25 seeds. In order to germinate the seeds, Petri dishes containing the extracts related to the extract were placed in suitable light conditions at a temperature of 25°C. Two weeks after treatment, germination percentage (%), germination rate index (number of day), radicle and plumule length (cm) and allopathic index were measured. Determination of free radical scavenging was performed by using the DPPH test. The samples’ absorptions were read at a wavelength of 517 nm with Epoch Microplate Spectrophotometer, BioTek Instruments, Inc., USA. Measuring the total phenols was performed according to Folin’s reagent method and the use of gallic acid as standard by using a spectrophotometer at the wavelength of 765 nm. Total flavonoid content was measured using a spectrophotometer at a wavelength of 510 nm through a standard curve of quercetin from Sigma-Aldrich. Flavones and flavonols were measured using 2% aluminum chloride and methanol at 425 nm. To isolate and measure the amount of polyphenols, an HPLC Agilent HPLC 1200 series model was used. Data were analyzed by using Duncan’s multiple range test (P< 0.05) by SAS, version 9.4 for Windows.
Results and Discussion
Among the studied plants, the highest and lowest amount of total phenol was found in Cocculus pendulus and Cassia obovata, respectively. The results showed, the highest amount of the total flavonoid in the extract, was achieved in Lavandula stricta plants collected in Kangan. The lowest (0.37 mg QUE. 100 g-1 DW) and highest (2.79 mg QUE. 100 g-1 DW) amount of flavon and flavonol was found in Cassia obovata and Cocculus pendulus, respectively. Also, antioxidant activity (I%) for Cocculus pendulus, Lavandula stricta and Solanum xanthocarpum were 77, 57 and 35%, respectively. Although, the lowest amount of antioxidant activity was found in Cassia obovata plants collected in Dashti. The results showed, the Lavandula stricta plants collected in Kangan had p-coumaric acid (PC) and ellagic acid (EA) by 0.565 and 1.28 mg g-1 DW. Among the phenolic acids evaluated, only catechin (0.262 mg g-1 DW) and p-coumaric acid (0.163 mg g-1 DW) were observed in the Cocculus pendulus plants collected in Kangan. The Cassia obovata plants collected in Dashti, had ellagic acid by 0.915 mg g-1 DW. The results of this study showed that the phenolic compounds identified in Solanum xanthocarpum juice were caffeic acid, chlorogenic acid, pi-coumaric acid, vanillin and hesperidin. Chlorogenic acid was the predominant phenolic compound by 457 mg g-1 DW. Laboratory results showed Cocculus pendulus and Solanum xanthocarpum extracts had the most inhibition effect on the germination and growth of Malva sylvestris at the concentration of 1000 µl L-1.
Conclusion
In this study, as the concentration of the extracts increased, the germination percentage, germination rate index (GRI), radicle and plumule lengths of Chenopodium album decreased significantly. Moreover, Solanum xanthocarpum juice showed the highest inhibition effect on Chenopodium album growth and germination at 1000 µl L-1. Due to the high potential allelopathy of the Cocculus pendulus and Solanum xanthocarpum, they can be used for Malva sylvestris and Chenopodium album control. Also, Cocculus pendulus extract can be used as a natural antioxidant source in related industries.
Research Article
Breeding and Biotechnology of Plant and Flower
F. Keykha Akhar; A.R. Bagheri; N. Moshtaghi; M. Fakhrfeshani
Abstract
Introduction
Flower color is one of the most significant characteristics in ornamental plant breeding. New varieties of various plants in relation to their flower color have been obtained by monitoring the expression levels of genes involved or regulating the flavonoid and anthocyanin biosynthesis ...
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Introduction
Flower color is one of the most significant characteristics in ornamental plant breeding. New varieties of various plants in relation to their flower color have been obtained by monitoring the expression levels of genes involved or regulating the flavonoid and anthocyanin biosynthesis pathway. Flavonoids possess significant and diverse biological functions. They are the major pigments for flowers, fruits, seeds, and leaves. They are natural products that contain a C6-C3-C6 carbon framework and are synthesized by a branched pathway that yields both colored and colorless compounds. The gene encoding chalcone isomerase (CHI) is among the genes and enzymes identified in the flavonoid pathway. This enzyme catalyzes the isomerization of naringenin chalcone into the corresponding flavanone. CHI enzyme belongs to the family of isomerases, specifically the class of intramolecular lyases. Chalcone isomerase has a core 2-layer alpha/beta structure and has attracted much attention recently due to its role in stress response and pigment production. One of the most effective methods of genetic engineering is the reduction of flower pigments by suppression of required enzymes for their biosynthesis. RNA interference (RNAi) has provided the tool for the investigation of genes involved in the production of flower color. Silencing of any gene in the anthocyanin biosynthetic pathway can result in reduced or inhibited anthocyanin production. RNAi technology is an effective gene silencing method and a powerful tool for studying gene function and development of new traits by transformation of viral RNA or hairpin RNA (hpRNA) constructs into plants. The processing of dsRNA into 21-23-nt small interfering RNAs (siRNAs), and the mediators of RNAi, triggers cognate mRNA degradation. The hpRNAi methodology simply requires a transgene construct containing an inversely-repeated sequence of the target gene flanked with a promoter and terminator which effectively function in plants.
Material and Methods
In this research, with the design and construction of chiRNAi, the transformation of the RNAi construct was carried out of Petunia plants. Potted plants of P. hybrida were grown under standard greenhouse conditions (16-17°C night temperature and 21-24°C day temperature and photoperiod 16/8 (light/dark)). The RNAi construct including the 530 bp cds of the chalcone isomerase (chi) gene and 741 bp of pdk gene as intron between chi sense and antisense were used for transient RNAi-induced silencing. The pBI121-chi530 plasmids were introduced into A. tumefaciens strain LBA4404 by electroporation method. Colonies of A. tumefaciens carrying the desired plasmid were screened by PCR with specific primers for chi gene. RNAi construct co-cultured with petunia’s leave. Samples was kept in dark condition for 3 days and then transferred to branch induction media. Samples were investigated for phenotypical changes and chi gene expression by qRT-PCR.
Results and Discussion
Transgenic lines showed a reduced number of pigments and a faded flower color. So that, in purple petunia, was shown 5 phenotypical groups. These groups was indicated different levels of chi gene silencing. In pink petunia was seen two groups of phenotypical changes. In these plants, chi-RNAi construct was reduced pigment production and so, these plants had faded colors in petals. Also, the chi gene expression was reduced in all transgenic lines. Generally, the results of this research showed that RNAi can be used as an efficient method for gene silencing. The application of gene silencing can indicate the gene’s function in biosynthesis pathways of various components such as anthocyanins. In addition, the chalcone isomerase gene was identified as one of the effective genes in anthocyanin biosynthesis pathway in Petunia plants that could be involved in the production of color in these plants; hence, chi gene silencing resulted in clear phenotypic alterations in this plant.
Conclusion
In general the concentration of the target mRNA in a particular tissue could be a factor that influences silencing efficiency. At very low levels of gene expression, small amounts of the silencing target, mRNA, could be completely degraded by the RNA-induced silencing complex (RISC), whereas the presence of higher amounts of the target mRNA may result in incomplete silencing, allowing some residual functional mRNA to be translated into the corresponding protein. This research demonstrated the hpRNA construct has been successfully established for floral tissues of P. hybrida. The hpRNA construct was developed for chi-RNAi silencing of one of the key genes in the anthocyanin biosynthetic pathway in Petunia flowers. The silencing of the chi gene is a prototype for the modification of the anthocyanin biosynthetic pathway in Petunia through gene suppression. This strategy could also be useful for rapid functional analysis of other genes involved in flower development.
Research Article
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.
Research Article
Growing vegetables
S. Mahmodi Soreh; A. Motallebi Azar; J. Panahandeh; G. Gohari; A. Jahanian
Abstract
Introduction
Potato (Solanum tuberosum L.) is an important food and cash crop having the first rank in the world from non grain crops to ensure food security. The tubers produced through the conventional propagation are characterized by low multiplication rate and susceptibility to pathogens. Microtubers ...
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Introduction
Potato (Solanum tuberosum L.) is an important food and cash crop having the first rank in the world from non grain crops to ensure food security. The tubers produced through the conventional propagation are characterized by low multiplication rate and susceptibility to pathogens. Microtubers are an ideal propagating material for producing high quality seed potatoes. Nowadays, the production, application, and biological risk assessment of nano-scaled products have attracted global concerns in various fields such as agricultural, biotechnological, medicinal, and plant sciences. Chitosan, a biocompatible polymer, has been widely utilized to improve the production of nano-chemicals, thereby improving crop growth, productivity, and immunity. Nanotechnology plays an important role in modern agriculture to address global challenges such as climate change, severity of plant diseases and the limited availability of important plant nutrients. Polymer-based nano-formulations have recently received the greatest attention with the key objectives of developing less harmful, plant growth promoting and protective agents of biodegradable and natural origin. Use of chitosan-based nanoparticles in agriculture field is still in a budding phase. Significant outcomes have been reported in in vitro and a few in vivo studies in plant growth and protection by chitosan-based nanomaterials.
Materials and Methods
MS medium containing 80 g of sucrose, containing glycine betaine at concentrations of 20 and 40 mg/l, chitosan at a concentration of 240 mg/l, glycine betaine 20 and chitosan 240 mg/l, glycine betaine 40 and chitosan 240 mg/l, 120 mg/l, glycine betaine nanocomposite coated with chitosan 120 and 240 mg/l and control treatment, as well as nonsalinity treatments with the same compounds and concentrations mentioned for salinity were cultured. The study was performed in randomized complete block design with three replications and sixteen treatment. Glycine betaine nanocomposite coated with chitosan were prepared at Maragheh University as follows. Chitosan, glycine betaine, and triphosphate are major consumables. First, chitosan was dissolved well with acetic acid under the influence of temperature. Then, a certain amount of glycine betaine was dissolved in distilled water and added to the chitosan. Tri-polyphosphate (TPP) was dissolved in distilled water at a certain volume ratio and added dropwise to the mixture of chitosan and glycine betaine. The precipitate obtained under the freeze-drying process lead to the preparation of its powder.
Results and Discussion
According to the comparison of the means, treatment of glycine betaine coated with chitosan nanocomposite at a concentration of 120 mg/l produced the highest number of microtuber during the experiment from the first month to the final month. The nanocomposite was more capable of improving growth and biomass than the bare ZnONPs in pepper. The application of the nanocomposite increased the concentration of chlorophylls (51%), carotenoids (70%), proline (2-fold), and proteins (about 2- fold). The supplementation of culture medium with the nanomaterials upregulated enzymatic antioxidant biomarkers (catalase and peroxidase) (Asgari-targhi et al., 2021). The highest mean microtuber weight was related to the nanocomposite treatment of 120 mg/l with a weight of 29 mg. In the microtuber diameter, this treatment had the highest value. The results of analysis of variance in Table 1 indicate that the effect of moderate salinity and the interaction of moderate salinity and nanocomposite treatments are not significant and the effect of experimental treatments is significant at the level of 5% probability. Due to the fact that the most important trait in the potato microtuberization is microtuber yield, so in the experiment, the highest microtuber yield was earned nanocomposite treatment with 131 mg and the lowest in control treatment with 87 mg. It seems that by using stress-reducing compounds such as glycine betaine and chitosan and nanocomposites, these compounds increase the amount of genes responsible for the formation of microtuber, and as a result, increasing the proteins involved in stresses induce more microtuberization. Also, nanocomposite materials, more assimilated materials may be transferred from the roots to microtuberization processes.
Conclusion
The microtuber produced in the glycine betaine coated with chitosan nanocomposite treatment produced the highest number of microtubers in the first, second, third, and final months. In treatments with moderate salinity in the first, second, third and final months, the number of microtuber and eyes and sprouted microtubers had the highest amount compared to the treatment without moderate salinity. Also, plants treated with glycine betaine voated with chitosan nanocomposite in the microtuber trate showed a greater effect than chitosan and glycine betaine with chitosan. According to the findings of this study, it seems that the use of nanocomposite materials in increasing the microtuber and reducing the vegetative growth of potato shoots has been made in Agria cultivar.
Research Article
Medicinal Plants
E. Nabizadeh; M. Haghshenas; Narges Dolatmand; K. Ahmadi
Abstract
Introduction
Stevia (Stevia rebaudiana) is one of the medicinal plants of the Asteraceae family that contains natural compounds, especially stevioside and ribaodioside A, which are estimated to be 150 to 400 times sweeter than sucrose. Plants are exposed to various environmental stresses during growth ...
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Introduction
Stevia (Stevia rebaudiana) is one of the medicinal plants of the Asteraceae family that contains natural compounds, especially stevioside and ribaodioside A, which are estimated to be 150 to 400 times sweeter than sucrose. Plants are exposed to various environmental stresses during growth and development under natural and agricultural conditions. Among these, drought is one the most severe environmental stresses affecting plant productivity. About 80–95% of the fresh biomass of the plant body is comprised of water, which plays a vital role in various physiological processes including many aspects of plant growth, development, and metabolism. Stevia is susceptible to various environmental stresses but the major effects are contributed by drought. Today, the fungal species Stevia rebaudiana is used as a biofertilizer and increases the production of secondary metabolites of economically valuable plants and also increases the growth and seed production of many plants. This fungal endophyte produces a significant amount of acid phosphatase for mobility in a wide range of insoluble or complex forms of phosphate, enabling the host plant to have adequate access to inactive phosphorus reserves in the soil. However, medicinal plants that are cultivated have often been reported to have lower abundance of arbuscular mycorrhizal fungi in the rhizosphere, which significantly reduces plant survival. Considering the coexistence role of mycorrhizal fungi in modulating the effects of drought stress, the aim of this study was to investigate the morphological, physiological and biochemical traits of stevia in response to the effects of mycorrhizal inoculation and drought stress.
Materials and Methods
This experiment was conducted to investigate the effect of P. indica endophytic fungus under water stress conditions on vegetative characteristics, physiological parameters and micronutrients of stevia. A factorial experiment was employed based a completely randomized design with four replications in the research greenhouse of Islamic Azad University, Mahabad Branch in 2017. The first factor was drought stress at four levels (25, 45, 60 and 80% of field capacity) and the second factor was inoculation of seedlings with fungus at two levels (no inoculation and inoculation with P. indica). Water stress was applied based on a combination of plant appearance symptoms (no wilting to severe wilting) and soil moisture. Investigated traits included root colonization, dry weight, leaf number, plant height, stem diameter, chlorophyll a, b, total chlorophyll, carotenoids, proline, soluble sugars, antioxidant power and micronutrients including copper, iron, zinc and manganese. To analyze the data variance, SAS 9.1 statistical software was used to analyze the variance of the data.
Results and Discussion
The results showed that the evaluated traits in the present study were affected by the main treatments of fungus and drought stress. Seedlings inoculated with P. indica endophytic fungi had the highest percentage of root colonization, growth parameters, photosynthetic pigment content, soluble compounds and micronutrients compared to no inoculation. Drought stress increased soluble sugars, proline content and antioxidant power of stevia leaves and decreased the other traits by increasing the stress level from 25 to 80%. The highest rate of root colonization (26.90%), stem diameter (3.21 mm) and carotenoid content (1.71 μg/ml) was observed in the treatment of plant inoculation with fungi and 25% drought stress. While the highest antioxidant power was found in the treatment of plant inoculation with fungi and 80% drought stress. According to the results of the present study, use of P. indica fungus had the most positive effect on the quantitative and qualitative characteristics of stevia medicinal plant compared to no fungus inoculation.
Conclusion
This study showed the positive effect of P. indica endophyte inoculation on quantitative and qualitative characteristics of root colonization, dry weight, number of leaves, plant height, stem diameter, chlorophyll a, b, total chlorophyll, carotenoids, proline, soluble sugars, antioxidant power and The micronutrients of calcium, iron, zinc and manganese showed stevia, and drought stress reduced the studied traits except for proline content, soluble sugars and antioxidant power. Inoculation of stevia seedlings with P. indica endophytic fungi at drought stress levels had the highest rate of root colonization, stem diameter, carotenoid content and antioxidant power compared to non-fungal inoculation. Therefore, due to the effect of biological compounds of natural origin and the production of plants with healthier active secondary compounds, the use of P. indica endophytic fungi can be recommended.
Research Article
Pomology
F. Karamnezhad; N. Moallemi; E. Khaleghi
Abstract
Introduction
Nitrogen plays an important role in the uniformity and quality of citrus trees. Several studies previously reported that a low level of nitrogen in citrus trees is generally caused a reduction in yield and fruit quality (Aziz, 1997; Khan et al., 2009). In this regard, applying urea is recommended ...
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Introduction
Nitrogen plays an important role in the uniformity and quality of citrus trees. Several studies previously reported that a low level of nitrogen in citrus trees is generally caused a reduction in yield and fruit quality (Aziz, 1997; Khan et al., 2009). In this regard, applying urea is recommended as the most suitable form of nitrogen for foliar application. The polyamines are included; putrescine, spermidine, and spermine which have been considered as plant growth regulators (Alcazar et al., 2010; Khezri et al., 2010). The role of nitrogen in vegetative and reproductive growth and yield, as well as the correlation between polyamines, flower induction and fruit set in other plants, were proved in previous studies. In this regard, the results of the current study will increase our understanding about the role of polyamines in the morphology of the tree and also the mechanism of regulating the alternate bearing of Kinnow mandarin leading to an approach method to address this problem.
Materials and Methods
To conduct this study a 17-year-old uniform of Kinnow Mandarin (Citrus reticulate Blanco) grafted onto Bitter orange (Citrus aurantium) rootstock, which grown in a commercial orchard, located in Dezful (Khuzestan Province in Iran). For sampling, the branches which possess leaves and nodes were selected from four sides of each tree, then leaves and nodes were collected at three different time points (one, three, and five weeks post-treatment). Samples were immediately frozen in liquid nitrogen after excision and transported to the Physiology Laboratory of fruit trees within 2h for determining the N fractions and polyamines. The concentration of N in dried leaves and nodes was determined using the colorimetry technique as described by Walling et al. (1989). The experiment was set up as a factorial treatment based on a randomized complete block design with three replications to investigate the effect of different concentrations of urea foliar application (0, 0.75%, 1.5%) on nitrogen and polyamines contents at different time points (Dec 22, Jan 5, Jan 20) followed by evaluating flower characteristics and yield in Kinnow mandarin plant. Data analysis including variance was carried out using MSTATC and SAS software. To compare the mean of polyamines and nitrogen in leaves and nodes, the cut-out method was used, and also for comparison of pistil dimensions, number of flowers, and yields, Duncan's multiple range test (DMRT) was performed.
Results and Discussion
Results indicated that polyamines concentration and nitrogen decreased during the period of time and also, in most cases, polyamines concentration was lower in the nodes than the leaves. High levels of polyamines and nitrogen were obtained in leaves and nodes which were treated with the foliar application of 1.5 % urea concentration after Jan 20. The polyamines content in leaves and nodes was greatly dependent on the spraying time and urea concentration used. Spermine (Spm) was the dominant polyamines in leaves and nodes with the highest values of 44.01 nmol/gF.W, 34.41 nmol/gF.W, respectively. Regarding the fact that flower density was higher in trees that treated with urea concentration of 1.5 % after Jan 5 y than other treatments, however, their yield was lower than the trees that treated on Dec 22 with the same urea concentration. This was probably due to the flower abscission as well as the fruit abscission in June. The results of this study showed that the highest yield was obtained with 1.5 % urea concentration after foliar application on Dec 22 compared with other treatments. Regarding the fact that flower differentiation in mandarin occurs during the late January until late February (in Dezful conditions), it can be explained that the foliar application on Dec 22 was performed before differentiation and consequently, the trees have received their required nitrogen. Also, the low-temperature is considered as natural inducer of citrus flowering in the Dezful, likewise, foliar fertilizer application in winter along with the natural factor (low temperature) stimulates flowering in a larger number of buds resulting in increasing the flowering. As nitrogen promotes vegetative and reproductive growth, it can be said that increasing the nitrogen content of leaves followed by transfering to the nodes, increases the number of buds, especially reproductive buds, which leads to an increase in flowering and yield. According to this study, the foliar application of urea in winter with 1.5% concentration can increase yield in Kinnow mandarin trees. Therefore, polyamines can play an important physiological role in flower development of Kinnow mandarin.
Conclusion
In this study, we focused on the effect of the foliar application urea during winter on leaves and nodes of Kinnow mandarin trees and investigated the polyamines, Put, Spm, and Spd contents upon treatments. In conclusion, the application of foliar urea in winter resulted in the significant endogenous increase of polyamines and N in the leaves and nodes of Kinnow mandarin trees. Also, yield, flower density, and pistil diameter were increased by spraying urea. There is a possibility that free polyamines affect on physiological processes.
Research Article
Growing vegetables
D. Akhgar; H.R. Karimi; S.R. Sahhafi; S.H. Mirdehghan
Abstract
Introduction
Drought stress in tomatoes reduces fruit quality and yield, also fall leaves and cause of blossom rot. It has been reported that drought stress reduces cell division and causes the stomata to close, followed by a decrease in the flow of carbon dioxide to the mesophyll cells of the leaf. ...
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Introduction
Drought stress in tomatoes reduces fruit quality and yield, also fall leaves and cause of blossom rot. It has been reported that drought stress reduces cell division and causes the stomata to close, followed by a decrease in the flow of carbon dioxide to the mesophyll cells of the leaf. Several methods have been proposed to overcome the drought stress in tomato plants, which can be mentioned the use of drought tolerance genotypes, genetic engineering to identify drought resistant genes and transfer them to sensitive plants, as well as the use of tolerancet rootstocks. It has reported that type of rootstock can effected on tolerance of tomato plants to drought stress. For this reason, the present study was conducted to investigate the effect of wild eggplant rootstock on the drought tolerance of two tomato cultivars.
Material and Methods
In order to find the effect of the wild eggplant rootstock on the tolerance of two tomato cultivars, a factorial experiment was conducted as completely randomized design with two factors. Factors were included irrigation period three levels of 3 (control), 6 and 9-day and grafting combination at 6 levels involved non-grafted Dafnis, non-grafted Isabella, self-grafted Dafnis, self grafting Isabella, Isabella grafted on wild eggplant rootstock (S. torvum), and Dafnis grafted on wild eggplant rootstock. The plants were exposed to drought for 54 days. At the end of experiment growth and physiological parmeters including leaf specific, plant height dry weight of shoot as well as photosynthesis parameters, RWC and plant nutrients were measured. The amount of leaf proline was measured according to Paquin and Lichasur methodusing a spectrophotometer at a wavelength of 515 nm. The phenolic compounds of the leaves were measured at a wavelength of 725 nm using a spectrophotometer (Isfendiyaroglu and Zeker, 2002). Also, the membrane stability index (ion leakage percentage) was measured according to Lutts et al.'s method (Lutts et al., 1996).
Results and Discussion
The results showed that with increasing irrigation period decreased the most of vegetative parameters, photosynthesis pigments, and mineral nutrients, so that, the highest value was showed at the 3-day irrigation period and the lowest value was at the 9-day irrigation period. Shoot weight decrese is probably due to morphological changes in plant roots, which is a plant response to drought stress. The results also showed that the interaction of irrigation period and grafted combination on some vegetative and ecophysiological parameters was significant. The lowest dry weight of shoot was observed at 9-day of irrigation period in plants of Dafnis grafted on torvum rootstock., Tthe highest dry weight root volume, leaf potassium and phosphorous concentration were at the 3-day irrigation period in self-grafted Dafnis plants.The results also showed that the amount of phenolic compounds in plants of Isabella grafted on torvum rootstock was the highest in 9 days irrigation period which may be due to the rootstock effect on the synthesis of these compounds in the scion. According to the results, the concentration of leaf magnesium in non-grafted plants increased with the increase of the irrigation cycle from 3 days to 9 days, althougth no significant difference was observed between self-grafted and non-grafted plants. In the 9-day irrigation period, the highest concentration of leaf magnesium was observed to non-grafted Daphnis plants, which was significantly different from other grafting combinations compounds except Daphnis self-grafted plants.
Conclusion
The results of the present study showed that drought stress had the greatest effect on dry matter, and the amount of photosynthetic indices and pigments in tomato plants. Based on the results of the present study, it was found that the most of the reduce vegetative and physiological parameters was observed in Daphnis cultivar grafted on the thorum rootstock, were significantly reduced compared to self-grafted or non-grafted plants, which it was due to the dwarfing effects of this rootstock or grafting incompatibility. According to the results of the present study, it can be postulated that in drought stress Isabella cultivars grafted on the wild eggplant rootstock had more growh than other combination grafting. Hence it proposed more studies in this case.
Research Article
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.
Research Article
Pomology
F. Javan; Y. Selahvarzi; M. Kamali
Abstract
Introduction
Today, in the commercial production of strawberries, short day cultivars are used due to having large fruits of desirable quality. Among the short day cultivars available in Iranare Camarosa, Atabaki, Gaviota, Queen Aliza, Paros and McDonance, which can be cultivated ...
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Introduction
Today, in the commercial production of strawberries, short day cultivars are used due to having large fruits of desirable quality. Among the short day cultivars available in Iranare Camarosa, Atabaki, Gaviota, Queen Aliza, Paros and McDonance, which can be cultivated at greenhouse. Titanium dioxide (TiO2) nanoparticles are one of the metal oxides that exist in three forms of rutile, brookite and anatase, which affect growth, enzymatic activity and photosynthesis. Reported titanium nano dioxide in the highest concentration used (11.5 mg/l) increases fruit formation percentage, leaf chlorophyll content, vitamin C content, fruit ripening index, fresh and dry weight of roots and shoots and yield of strawberries. In another study, it was shown that titanium dioxide treatment under drought stress can increase photosynthetic pigments, total soluble solids, vitamin C, phenol, flavonoid, anthocyanin, and antioxidant activity, and it also improved plant performance. increase the strawberry cultivar Ventana compared to the control treatment. In a research found that spraying titanium increases the biomass, fertility and quality of peach fruit. It has alsow been showed that the pomegranate size of flowers and fruits increased with using titanium nano dioxide, and this can increase the quantity and quality of Alberta peach cultivar. Foliar application of titanium nano dioxide in cucumber has been reported to increase photosynthesis and phenolic content and reduce lipid peroxidation. In a research, it was shown that titanium dioxide nanoparticles increased photosynthesis rate, water conductivity and transpiration rate in tomato leaves. Despite the effect of titanium dioxide nanoparticles on the quantitative and qualitative improvement of some agricultural products, the researches conducted on strawberry plants were not complete or were only conducted on a specific variety. Therefore, with the aim of investigating and comparing the morphological and biochemical traits of some commercial strawberry cultivars under the effect of foliar spraying with titaniumdioxide, the above research was conducted.
Materials and Methods
This research was conducted to investigate the effect of nano titanium dioxide foliar spraying on four strawberry cultivars in the hydroponic greenhouse of the Department of Horticultural Sciences, Faculty of Agriculture, Ferdowsi University of Mashhad in 2020-2021. Experimental treatments included 4 levels of titanium nano dioxide (0, 5, 10 and 20 mg/l) and 4 strawberry cultivars (Sabrina, Paros, Gaviota and Camarosa) with 4 replications. The research was done in a factorial manner based on a completely random design. JMP 8 software was used to perform variance analysis and compare the averages of the measured traits. Means were compared using Tukey test at 5% probability level and graphs were drawn using Excel 2010 software.
Results and Discussion
According to the tables of mutual effects of titanium dioxide nano treatments and varieties, it can be found that the application of titanium dioxide nanoparticles had a positive effect on the desired characteristics in all four studied strawberry varieties. So that the application of different levels of titanium dioxide nano particles causes a significant increase in quantitative traits (number of leaves, leaf area, root length, fresh and dry weight of aerial and root parts, photosynthetic pigments) The yield-dependent traits compared to the control plants were found in strawberry-strawberry cultivars. Nano titanium dioxide had an effect in increasing the number of fruits and vegetative traits of all investigated cultivars, in such a way that, on the one hand, with a balanced increase in vegetative growth, and on the other hand, improving the efficiency of photosynthesis and absorption through the roots and increasing the percentage of fruit formation. , increased the yield per plant. Also, sprinkling of titanium nanoparticles on all levels caused a significant increase in juice pH, TSS, TA, vitamin C, anthocyanin, total phenol, flavonoid and in general qualitative traits compared to the control. In the treatment of nano titanium dioxide, especially at the level of 10 mg/liter, better results were observed.
Conclusion
According to the results, the use of Paros and Gaviota cultivars is recommended to farmers and agricultural researchers due to its high yield and good quality.
Research Article
Pomology
E. Safavi; M. Yadegari; S.A. Mousavi; B. Haghighati
Abstract
Introduction
Water shortage is very frequent in many countries, and, together with the rising demand for industry, growth of human population, climate change and specifically the trend towards irrigated agriculture, has led to widespread problems of water scarcity, especially in Middle East countries. ...
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Introduction
Water shortage is very frequent in many countries, and, together with the rising demand for industry, growth of human population, climate change and specifically the trend towards irrigated agriculture, has led to widespread problems of water scarcity, especially in Middle East countries. This situation imposes the need to optimize water use in all human activities. Among the different productive uses of water, agriculture is by far the main water user in most water scarce regions and, consequently, any potential improvement in the use of the available water resources may play a significant role toward achieving a more sustainable use of water. Plant responses to water deprivation are usually monitored through selected morphological and physiological parameters which have been proven to be good indicators of drought in different studies. Some of the most important standards for evaluating plant genotypes under drought stress are measurements of morphological parameters such as height, leaf characters and root growth.
Materials and Methods
To compare the growth response of different almond cultivars to different levels of water stress, an experiment was conducted as a split plot in the base of randomized complete block design with three replications in the Agricultural and Natural Resources Research Center of Chaharmahal and Bakhtiari Province in two growing season 2019-2020 and 2020-2021. Different irrigation periods based on the percentage of usable soil moisture between filed capacity to wilting point, including 70% filed capacity (control or no stress), 50% filed capacity (mild stress), 30% filed capacity (medium stress) and 10% of field capacity (severe stress) were considered as the main factor of the experiment. The sub-factor included 14 commercial cultivars of almonds (Mamaei, Rabi, Saba, Araz, Eskandar, Aidin, Shahrood 6, 7, 8, 10, 12, 13 and 21 and GN vegetative rootstock), all of which were grafted on GN rootstock. In this study, uniformly grafted seedlings in terms of age, stem diameter and height were selected and planted. In the second year after planting the seedlings, in order to apply drought stress, tubes for hygrometer (TDR) were installed in each experimental plot and based on soil moisture content, irrigation cycle was determined for different treatments.
Results and Discussion
In both years, three months after applied water stress growth traits and nutrient concentrations in the leaves of treated seedlings were measured. Based on the results of analysis of variance, the morphological traits of almond seedlings were significantly affected by cultivar type and drought stress level. In all almond cultivars, the highest height was belonged to seedlings that were grown in non-stress conditions and with increasing the drought stress intensity, the height of almond seedlings was decreased. Under severe drought stress, GN and Mamaei cultivars had the highest (183.93 cm) and the lowest (94.60 cm) height, respectively. Seedling height in GN, Shahrood 12, Saba and Shahrood 10 cultivars showed the lowest decrement under severe drought stress. In all cultivars, drought stress caused a significant reduction in the length and width of the seedlings crown, and the greatest decreasing was recorded in severe drought stress (10% FC). Under severe drought stress, cultivar GN had the largest crown and cultivars Rabi, Shahrood 7 and Eskandar had the smallest crown. Increasing the drought stress intensity significantly reduced the branches growth of seeding in terms of number and length of sub-branches. As the intensity of drought stress increased, the length of sub-branches decreased however the number of intermediates in sub-branches increased. In non-stressed condition, the cultivar GN had the longest branch (55.95 cm), which was significantly higher than the other studied almond cultivars. The shortest branches were also observed in Saba (29.94 cm) and Eskandar (29.47 cm) cultivars. Increasing drought stress caused a significant reduction of leaf area in all studied cultivars and the highest decreasing was observed under severe drought stress. The GN (37.76 cm²) and Shahrood 10 (31.81 cm²) had the highest leaf area in non-stress and drought stress conditions. Under severe drought stress (10% FC) cultivar Shahrood 6 showed the lowest leaf area. The results of this study showed that increasing the intensity of dehydration significantly reduced the amount of nitrogen, phosphorus, manganese and zinc in the leaves of the studied cultivars of almonds, however, the amount of potassium and iron in stressed plants increased under drought stress. Based on the results of the present study, under severe drought stress the GN, Shahrood 8 and Shahrood 12 cultivars in terms of growth indices including seedling height, stem diameter, canopy growth, branch growth and concentration of macro and micro elements was superior compared with the other studied cultivars.
Conclusion
Based on the results of this study, drought stress significantly reduced growth indices and nutrient concentrations, although the reaction of almond cultivars to different levels of drought stress was different. In this study, among the studied almond cultivars GN, Shahrood 8 and Shahrood 12 cultivars in terms of growth characters including seedling height, stem diameter, canopy growth, branch growth and concentration of macro and micro elements showed higher tolerance to different level of drought stress. These cultivars less affected by the high intensities of dehydration. Therefore, GN, Shahrood 8 and Shahrood 12 cultivars can be used in future studies to evaluate the possibility of cultivating these cultivars in areas with water deficit.
Research Article
Growing vegetables
A. Omidi; A.R. Astaraei; H. Emami
Abstract
IntroductionChromium pollution of the soil due to natural processes or industrial activities such as metal refining, chrome plating, stainless-steel production, leather tanning, and chemical dye production is a globle environmental issue. Excessive soil Cr levels cause detrimental effects on plant physiological ...
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IntroductionChromium pollution of the soil due to natural processes or industrial activities such as metal refining, chrome plating, stainless-steel production, leather tanning, and chemical dye production is a globle environmental issue. Excessive soil Cr levels cause detrimental effects on plant physiological processes including photosynthesis, water relations and mineral nutrition as well as the growth of roots, stems and leaves, which may decrease the biomass and yield of plants. Currently, soil application of organic amendments particularly humic acid seems to be an effective procedure to enhance relative plant tolerance to Cr stress. Humic acids are complexes of heterogeneous poly electrolytes with abundant functional groups that act as a weak poly electrolytic acid. Their structures, the degree to which these functional groups are protonated or ionized and environmental conditions influence the interaction between HA and soil pollutants. The complex compounds form by interaction of HA and heavy metals that cannot be uptaken by plants. Humic acid may play a significant role in the mobility and uptake of Cr which leads to a significant increase in plant biomass and growth. The aim of this research was to investigate the ability of humic acid to reduce Cr uptake and translocation by lettuce (Lactuca sativa L.) from Cr-contaminated soil. Materials and MethodsThe present study through a greenhouse pot experiment was conducted in the greenhouse of Ferdowsi university of Mashhad. The experiment was arranged in a factorial manner in a randomized complete design with three replications and treatments consisted of 3 levels of Cr (0, 25, and 50 mg kg-1as K2Cr2O7) and 3 rates of HA (0, 5 and 10 %). The soil samples were dried at room temperature, ground and sieved with a 2-mm mesh screen for further analysis. The bioavailable concentrations of Cr in the soils were assessed by DTPA. Three lettuce seedlings were grown in each pot containing five air-dried soil and watered to a near field capacity with distilled water as needed. After 100 days plant tissues were harvested, carefully washed with deionized water and the leaf, stem and root parts separated. All of them were oven-dried at 65-75 °C to constant weight and the dry weight of lettuce tissue samples was recorded. To determine the Cr concentrations, the tissues were ground, passed through a 0.3-mm sieve and digested in di-acid mixture (HNO3:HClO4). Concentrations of Cr in the digested solutions and soil extractions were determined using an Inductively Coupled Plasma Optical Emission Spectrometry (ICP OES). Translocation factor (TF) is determined from the ratio of the concentration of Cr in the plant’s shoots compared to that in the plant’s roots. Bioaccumulation factor (BAF) was evaluated as defined as the accumulated concentration of Cr in plant divided by concentration to that in respective soil. A two-way analysis of variance was done by using a statistical package, JMP version 8.0. The differences between the treatments were determined using LSD multiple range tests at significance level of P ≤ 0.05 and P ≤ 0.001.Results and DiscussionThe results of the present study clearly demonstrate that all Cr treatments significantly reduced leaf, stem, shoot and root dry weights. In unamended soils, both Cr treatments alone reduced leaf, shoot, stem and root dry weights 83%, 101%, 207% and 65% (for Cr 25 mg kg-1) and 194%, 219%, 355% and 92% (for Cr 50 mg kg-1) respectively as compared to control. Using HA (5 and 10%) and Cr treatments (25 and 50 mg kg-1), showed that leaf, shoot, stem and root dry weights were significantly increased as compared to Cr contaminated control. The lowest values of these parameters were recorded in Cr treatments without addition of HA, whereas at each Cr level, the highest values of them were obtained with application of 10% HA. The Cr concentrations in shoot and root samples significantly were affected by adding HA and Cr levels in soil. It was observed that Cr contents in shoots and roots, transfer factor and bioaccumulation factor of shoots and roots significantly increased by increasing soil Cr levels. Moreover, HA application negatively affected Cr content in shoot compared to Cr treatment alone. The interaction of chromium and humic acid caused a significant decrease in the concentration of chromium in the aerial parts, the shoot accumulation factor and a significant increase in the concentration of chromium in the roots and consequently reduced translocation factor. The highest value of Cr in shoot (47.7 mg kg-1) was obtained in those plants grown in soil with addition of 50 mg kg-1 Cr alone, whereas at each Cr level the lowest value of Cr in shoot was found in those plants grown in soil with the application of 10% HA. HA application in soil increased Cr concentration in root compared with Cr contaminated control. The maximum Cr concentration in the root (367 mg kg-1) and root bioaccumulation factor (28.5) was obtained after exposure to 50 mg kg-1 Cr +10% HA treatment. Also, the regression models showed that the transfer factor and shoot bioaccumulation factor decreased significantly and linearly with increasing shoot dry weight. Moreover, the regression model of shoot dry weight and shoot bioaccumulation factor was able to predict traslocation factor and shoot bioaccumulation factor with Adjusted R2 = -0.78** and R2 = -0.93**, respectively. ConclusionResults demonstrated that Cr toxicity markedly reduced plant growth parameters for instance leaf, stem, shoot and root dry weight and enhanced the concentration of Cr in shoot and root as compared to control. Humic acid application in Cr contaminated soil induced increased plant biomass, root bioaccumulation factor, Cr contents in roots and reduced Cr concentration in leaves, translocation factor and shoot bioaccumulation factor. Therefore, the application of HA specially at higher dose (10%) seems to be a cost-effective and environmentally friendly method for the restriction of Cr accumulation and its transfer from contaminated soil to edible parts of lettuce, thus helping to enhance food security.
Research Article
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.
Research Article
Growing vegetables
N. Zeinali Pour; F. Aghebati
Abstract
Introduction
Drought stress is one of the most common environmental stresses that limits agricultural production through disruption of physiological processes and reduces plant performance. Since in most parts of the world, including in Iran, melon plants and generally pumpkins are cultivated in hot ...
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Introduction
Drought stress is one of the most common environmental stresses that limits agricultural production through disruption of physiological processes and reduces plant performance. Since in most parts of the world, including in Iran, melon plants and generally pumpkins are cultivated in hot and dry areas, and in these areas the main challenge is due to the limitation of suitable water for agriculture, the possibility of various types of stress, including water deficit stress (partial or severe) in the cultivation of these plants is relatively high. From this point of view, it seems necessary to study and know the tolerant cultivars and masses and ways to improve water management. Among the physiological characteristics, leaf water status, membrane stability, photosynthesis changes and related factors are of special importance in relation to tolerance of stressful conditions and especially dehydration. A review of scientific sources shows that due to the relative importance of melons among fruit vegetables, no comprehensive research has been done on the effect of water stress on the yield and stress level evaluation indicators in Garmak and Dudaim groups. This research has tried to investigate and evaluate this issue in some products of this group of vegetables that have been less studied.
Materials and Methods
This experiment was carried out in the form of a split plot design in the form of randomized complete blocks and in four replications in the Mahan greenhouse complex located 25 km from Kerman province. Experimental treatments include; There were three plants (Shahdad and Isfahan cantaloupe (Garmak) and Birjand dudaim (Cucumis melo group dudaim)) and three levels of irrigation in order to apply stress (starting irrigation at matric potentials of -45 (control), -55 and -65 kPa). The parameters of net photosynthesis rate, stomatal conductance, leaf transpiration rate, leaf chlorophyll index, water potential, osmosis and turgor potential of leaves, water use efficiency and leaf relative humidity were measured and evaluated.
Results and Discussion
Based on the results of the first and third tables, the three population were different in the changes in the net rate of photosynthesis under different levels of dehydration stress, but the change process in them was largely similar. The highest rate of net photosynthesis and leaf stomatal conductance was obtained in Isfahan cantaloupe population plants under control irrigation (-45 kPa), which, of course, did not have a significant difference with plants under -55 kPa dehydration stress, and the lowest rate of these traits in Birjand dudaim under irrigation at matric potential -65 kPa was measured. A more severe level of dehydration stress (starting irrigation at matric potential of -65 kPa) reduced the net photosynthetic rate in all three plants compared to control irrigation (-45 kPa). It seems that under the conditions of this experiment, the reduction of the relative humidity of the leaves occurs following the reduction of the water potential in the leaves and leads to the closing of the stomata in order to increase the resistance of the mesophyll cells against the dehydration stress and parallel to these changes, the reduction it happens in the amount of stomatal conductance and as a result the rate of net photosynthesis. The rate of leaf transpiration in matric potentials of -55 and -65 kPa has decreased significantly compared to control irrigation. The decrease in transpiration rate in plants under stress is probably due to stomatal closure and reduction of stomatal conductance. Plants under stress prevent excessive water loss through transpiration by regulating stomata. Based on the results of the second and fourth tables, by measuring the water potential, osmosis and turgor potential of the leaves of the three population used, it was shown that the water potential of the leaf decreased with the increase in the water stress levels. The slope of this decrease is such that the potential values are equal to the osmotic potential values of the leaf and the turgor potential, which is the result of the difference between the osmotic and water potentials of the leaf, also decreases, but it is the turgor pressure that has increased and in a more positive way. even at the end of the stress period and at the most extreme level of stress, it reaches zero. This same turgor pressure maintains the normal state of the membrane in cells under dehydration stress. In fact, the extreme level of water stress in this experiment significantly reduced the osmotic potential of the leaf. The highest amount of osmotic potential (8.5 Bar) for these plants was obtained in the usual or control irrigation treatment and the lowest (22 Bar) in the more severe level of dehydration stress treatment (watering as soon as the matric potential reaches -65 kPa) was obtained. At matric potentials of -45 and -55, there was no significant difference between the three population in terms of leaf relative humidity percentage, but in Garmak and Dudaim populations, the relative humidity of leaves was significantly reduced by applying stress at the matric potential of -65 kPa. This is despite the fact that in the Isfahan cantaloupe, the decrease in the relative humidity of the leaf was not significant. The existence of this difference in the reduction of the relative humidity of the leaves in the conditions of stress between the three plants may be due to the genetic differences in the ability of the stomata of the plants to lose water. In fact, more drought tolerant population (Isfahan Garmak) compared to Shahdad Garmak and Birjand dudaim have better maintained relative humidity until the end of the stress.
Conclusion
Plants with the ability to regulate osmosis can be considered as drought tolerant plants. This adjustment in the plants of this experiment occurred in the condition that in all three population, the osmotic potential decreased by -19 to -22 Bar. This event is to some extent guaranteeing the performance of pure photosynthesis, although at a low rate in these plants, in the condition that the water potential of the cell has become negative at the level of severe water deficit stress, at the end of growth.
