Journal of Plant Process and Function

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Ladan Bayat 1, Mehri Askari*2 Department of Biology, Faculty of Science, Arak University (Received: 29 November 2012 Accepted: 4 May 2013) Abstract: Plant growth promoting rhizobacteria are beneficial bacteria that increase growth of plants and induce resistance to various stresses. SO2 air pollution is one of these stresses that is known as a strong damaging air pollutants. Persian clover is one of legume family plants that consider as a forage crop and can form symbiosis with Rhizobium bacteria. In this study, the effects of Rhizobium (native and standard strains) on amounts of photosynthetic pigments and phosphorus and potassium elements of Persian clover under different concentrations of SO2 (0, 0.5, 1, 1.5 and 2ppm) were evaluated. The results showed that inoculation has beneficial effects on the amounts of photosynthetic pigments and phosphorus and potassium content in compared with non-inoculated plants. High concentrations of SO2 (1, 1.5 or 2ppm) caused a significant decline in the amounts of photosynthetic pigments and phosphorus and potassium elements of clover plant in compared to the control plants, however low concentration of SO2 (0.5ppm) had positive effects on measured parameters. Inoculation of Persian clover with two strains of Rhizobium decreased negative effects of high concentrations of SO2 on the amounts of photosynthetic pigments and phosphorus and potassium elements. The highest values of these parameters were measured in combination of the local strain plus 0.5ppm of SO2. It was suggested that Rhizobium could increase plant resistance and tolerance against abiotic stresses such as air pollution.

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Effects of decreased ozone and increased UV radiation have been studied by many researchers. The aim of this study was to investigate the effects of UV-B and UV-C radiations on Melissa Officinalis L and to study the Impact of salicylic acid in reducing the harmful effects of radiation on plants. The Melissa Officinalis L plants were treated with 28_+2 ºC temperature for about 60 days. The light intensity was 150 µ E mˉ² Sˉ¹ and the lightness-darkness condition was8-16 hours. UV treatment was applied after the six-leaf stage and UV-B radiation was applied for a period of 15 days in every other day the time for each application was 20 minutes. But UV-C radiation was applied for 15 days in every other day and time of each application was 8 minutes. Salicylic acid was sprayed on the plants after the six-leaf stage with a concentration of 1 Mm. The results indicated that the UV-B and UV-C radiations led to reduction in dry and wet weight, root elongation and shoots. The radiations also reduced the photosynthetic pigments (chlorophyll a, chlorophyll b and carotenoid) and sugar rate and total soluble proteins amount. The Malondialdehyde and phenylalanine ammonialyase compounds rate and UV- absorbing compounds were increased under the effect of UV-B and UV-C radiations. Surveying results showed that treatment with salicylic acid caused a reduced damage to the plant which had been created due to UV-B and UV-C radiations and was able compensate for changed factors that had been changed because of ultra violet radiations.

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In this research the effect of four concentrations of nickel and copper (25, 50, 100, and 200 µM) on root and shoot length, fresh and dry weight, leaf surface, and photosynthetic pigments (Chlorophyll a, b and carotenoids), sugar, malondialdehyde, hydrogen peroxide content and antioxidant enzyme activity (CAT and APX) in Okra plants were evaluated. The results showed that in those plants which were treated with all concentrations of copper and nickel, the content of photosynthetic pigments and leaf surface were reduced significantly in comparison with control. In this investigation it was found that shoot and root length, dry weight and fresh weight of shoot and root which were treated with concentrations 50, 100, and 200 µM of cupper and 100 and 200 µM of nickel were reduced significantly when compared with the control. Content of soluble sugars in shoot and root plants which were treated with all concentrations of nickel and concentrations 50, 100, and 200 µM of cupper increased significantly in comparison with the control. Also, content of malondialdehyde, hydrogen peroxide content and antioxidant enzyme activity (CAT and APX) increased significantly in shoot and root plants which were treated with concentrations 50, 100, and 200 µM of copper and nickel when compared with control.

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Madagascar periwinkle is one of the important medicinal plants belonging to Apocynaceae family. In this study the effects of nano zinc oxide on growth index wet and dry weight, leaf surface, photosynthetic pigments, total carbohydrates and amount of elements were investigated. Experiments were designed completely randomized in greenhouse culture conditions with three replications. Zinc oxide nanoparticle in different concentrations (2, 4, 5, 10 and 15 µM) and hogland nutrient as control was given to Catharanthus roseus plant for 70 days. In addition to study the symptoms of zinc deficit used zero concentration. The results indicate that nanooxide in concentrations higher than 2 µM reduced wet and dry weight, photosynthetic pigments, total carbohydrates, iron and phosphorus. Also the results indicate that uptake of zinc in nano scale is higher. Uptake of potassium and zinc increased with increasing the concentration of nano zincoxide. This means intraction between these elements is positive while the intraction of phosphorus and iron with zinc element is antagonisticand with increasing concentration of nano-ZnO the uptake of these elements will be reduced.

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Drought stress stimulates the production of reactive oxygen species (ROS) in chloroplasts. ROS laed to lipid peroxidation and damage to the cell membrane. In the current study, the effect of different concentrations of silicon were examined on oxidative stress caused by drought in fennel plant. The experimental design was a split plot based on RCBD with three replications in which irrigation regimes includingirrigation at 100%, 70% and 40% of field capacity were assigned as main plots and five levels of silicon foliar sprays (0, 2.5, 5, 7.5 and 10 mM) were allocated to sub plots. The experiment was conducted in 2009 at the Zabol University research farm, Zabol, Iran. The results showed that drought stress significantly decreased chlorophyll a, chlorophyll b, carotenoids, leaf relative water content and catalase activity. In drought conditions, malondialdehyde levels and electrolyte leakage showed a 2 -fold increase over the control. Silicon treatment (7.5 mM) accompanied by drought, increased the activity of peroxidase and ascorbate peroxidase, proline and soluble sugars by 18, 25, 14 and 28%, respectively and decreased malondialdehyde and electrolyte leakage by 30 and 28%, respectively over the control, suggesting that silicon spraying (5 and 7.5 mM) could increase the ability of plants in response to drought stress by strengthening the antioxidant system of the plant and increasing osmolytes, and have protective effect against lipid peroxidation, induced by stress.

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Cadmium (Cd) is easily absorbed by the root system in many plant species and due to its solubility in water and toxicity is considered as a major pollutant. The aim of this study was investigation of cadmium toxicity on some physiological characteristics of lentil seedlings. So, two-week-old plantlets were treated with different concentrations (0 as control, 0.125, 0.25, 0.5, 1, 2.5 and 5 μM) of cadmium chloride for 10 days and then the amounts of photosynthetic pigments, proline and soluble proteins were investigated. Survey results indicated that with increasing in cadmium concentration, a significant decrease was observed in photosynthetic pigments. In addition, the cadmium significantly was increased amount of proline in treated seedlings compared with control. Also, cadmium has imposed drastic decrease in total soluble proteins and the amount of proteins declined progressively with increasing concentrations of cadmium. Due to a decrease in protein content and photosynthetic pigments, the present results allow us to conclude that the lentil plants showed a negative response to cadmium toxicity. In addition, to overcome cadmium stress, seedling have increased the amount of non-enzymatic antioxidant compounds such as proline.

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To study the effect of salinity on photosynthesis pigments, fluorescence and antioxidants of three varieties of peanut leaf as an indicator of resistance to salinity, research was carried out as factorial arrangement based on completely randomized design with three replications in the greenhouse of University of Guilan in 2013. The experiment consisted of a combination of 4 different salinity levels (0, 50, 100 and 150 mM) and three cultivars of peanut (Local Guilan, ICGV96177 and ICGV03060). The results showed that the interaction between cultivars and salinity measurement on characteristics of chlorophyll a, chlorophyll a + b the maximum fluorescence (Fm) initial fluorescence (F0), Peroxidase and phenol were significant except for carotenoids. This study indicated that increasing the concentrations of NaCl, Phenol and peroxidase increased the amount of chlorophyll a and b, and chlorophyll fluorescence yield decreased, and in general the local cultivar of Guilan was the most resistant one under different levels of salinity.

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To investigate the effect of salicylic acid (0, 50 and 100 mM) on some physiological characteristics of henna, medicinal-industrial plant, under drought stress (0, -2 and -4 bar induced by PEG 6000) a factorial experiment based on completely randomized design was carried out in the research greenhouse of agriculture faculty of Shahid Bahonar University of Kerman. The content of photosynthetic pigment, protein, antioxidant activity of catalase and poly phenol oxidase and dry matter production were measured as some physiological response of henna. All measured traits affected significantly by drought stress (p<0.01). The highest amount of these traits except the activity of catalase and poly phenol oxidase were recorded for non-stress condition. The only trait that was not affected by salicylic acid significantly was the activity of poly phenol oxidase. The application of 50 mM salicylic acid led to the highest amount of these traits. The interaction of salicylic acid * drought stress was significant only for chlorophyll a, total chlorophyll, protein content, catalase activity and dry matter. Based on the obtained results, it can be concluded that application of salicylic acid on henna could largely improve the deleterious effects of drought stress through modification of physiological responses.

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Abstract In this study, the effect of leaf spray of two salicylic acid concentrations, 100 and 500 µM, was studied on the some physiological and biochemical properties of grape cv. Ghizil Uzum in saline (EC=10) and non-saline (EC=2) conditions. The experiment was conducted in a Completely Randomized Design with 4 replications under greenhouse condition. The results showed the significant decreases in fresh and dry weights, water content, photosynthetic pigments, photochemical efficiency of PSII and total protein, starch and K+ concentrations of leaves in saline condition. But, the concentration of free amino acids, soluble sugars and Na+ were increased. The salt affected the plant antioxidant system by induction of superoxide dismutase, peroxidase and catalase activities and increasing malondialdehyde and H2O2 contents of leaves. Salicylic acid application in both concentrations in non-saline condition and in 500 µM in saline condition has not notable effects on studied parameters. Application of 100 µM salicylic acid in saline condition could ameliorates the negative effects of salt stress in grape cv. Ghizil Uzum by increasing the osmolytes and carotenoids concentrations, photochemical efficiency of photosystem II, capacity of antioxidant system and specially decreasing the Na+ ions transfer to growing plant organs.

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The current experiment was designed to evaluate the effect of plant growth promoting rhizobactria (PGPR) on chlorophyll fluorescence and some physiological parameters in basil (Ocimum basilicum L.) leaf under salinity stress. The experiment was conducted in factorial arrangement based on completely randomized design. Treatments were four levels of salt stress (0, 40, 80 and 120 mM of NaCl) and three levels of PGPR inoculation (control, coinoculation with either Azotobacter+Azospirillum or Azospirillum+Pseudomonas+Bacillus). The results showed that increasing salinity stress significantly increased both minimum and maximum fluorescences (Fo and Fm) and quantum yield of non-regulated non-photochemical quantum efficiency [Y(NO)], while decreased variable fluorescence (Fv), maximum photochemical quantum yield of photosystem II (Fv/Fm) and photochemical quantum yield of photosystem II [Y(II)]. The trend of chlorophyll content and chlorophyll a and b (in control treatment) increased at low and medium level of salinity while decreased at higher salinity levels. However, with increasing the salinity level the relative water content (RWC) as well as the amount of carotenoids decreased and electrolyte leakage increased. Inoculation of basil plants with PGPR significantly reduced Fo and Y(NO) while increased Fv, Fv/Fm and NPQ as compared to the uninoculted control. Among the biological treatments, Azospirillum+Pseudomonas+Bacillus by 12% increase in Y(II) and 16% decrease in Y(NO), showed the most positive effects on plant photosynthetic system. Biological treatment also improved chlorophyll content, chlorophyll a and RWC and reduced electrolyte leakage. In conclusion, the current results indicated that the ameliorate effect of PGPR particularly coinoculation of Azospirillum+Pseudomonas+Bacillus on chlorophyll fluorescence and physiological parameters improvement of basil seedling leaves under salinity stress.

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One of the important goals of plant physiology in water ecosystems, is biomass and growth increment of green microalgae which led to access to their valuable production. In this regard, many factors are able to influence the increment and decrement of algal biomass. In this research different levels of vanillin (C₈H₈O₃), as 0 (control), 10, 25, 40, 50, 70, 90 and 100 mg. L^-1, were investigated during 24 days on cell number, fresh weight, dry weight and some of physiological indices (such as total sugar, reducing sugars, protein and photosynthetic pigments) in two algae, D. badawil-UTEX2538 and D. salina-UTEX200. All experiments were performed as completely randomized design (CRD) in three replications. The highest number of cells was observed at 25, 40 and 50 mg. L^-1 vanillin treatments. In D. bardawil, maximum specific growth rate (SGR) and minimum doubling time (DT) of cells were observed at 50 mg. L^-1 and in D. salina those were observed at 25 and 40 mg. L^-1. Fresh weight, dry weight and total sugar were increased by the most of treatments, but protein and reducing sugars were decreased compared to control. Chl a, total Chl and total carotenoid were increased only in D. bardawil, but Chl b and beta carotene showed decrements. D. salina had a higher growth rate but lower content of protein, total sugar and reducing sugars than D. bardawil. Overall, in contrast to some of the previous researches, vanillin which has phenolic nature induced faster growth rate and cell division in algal suspensions and also in the most of the cases, it led to improvement of physiological indices.

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     Salinity is a major environmental factor limiting plant growth in natural ecosystems. Glycyrrhiza glabra is an important Fabaceae (perennial plant) that its root and rhizome extracts are used in food, health, medical and pharmaceutical industries. To assess the effect of methyl  jasmonate (MeJA) and salinity on licorice, an experiment was conducted as factorial based on completely randomized design with three replications.  Accordingly, plants were exposed to the concentrations of 0, 100, 200 and 300 mM NaCl for five weeks, 24 h after foliar application of 0, 50 and 100 µM MeJA. In our experimental condition, a significant decrease in shoot dry weight, shoot and root fresh weights, plant height, leaf relative water content (RWC), Ca concentration of shoot and root and root Mg concentration were observed at 300 mM NaCl, while total chlorophyll, chl a and chl b concentrations and carotenoids were not affected significantly by salinity. Also, NaCl at 300 mM caused a significant increase in proline and total soluble sugar contents, Na⁺/K⁺ ratio and dry weight of roots. Results showed that exogenous application of MeJA at 50 µM level improved plant tolerance to salinity up to 200 mM NaCl and increased growth parameters, photosynthetic pigments, soluble sugar and proline content of shoot and root in comparison with control. Moreover, the application of MeJA caused a significant increase in Mg concentration of the shoot and root of control plants.

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Salinity is one of the major challenges to increasing crop productivity. Besides these, in order to investigate of  proline and salicylic acid in the modulation of salt stress on soybean (Glycine max L.) , an experiment was conducted as split plot arrangement in a randomized completely design with four replication in 2016 in College of Agriculture, Shahrekord University. Main plot included three level irrigation by saline water with electrical conductivity 2 (control), 5 and 10 dS m^-1 NaCl) and sub plot in four level of foliar applied (10 mM proline, in combination with 10 mM proline + 3 mM salicylic acid, 3 mM salicylic acid and sprayed with water (control)). The results showed that the 5 and 10 dS m^-1 NaCl lead to increased and decreased of photosynthetic pigments compared with the control, respective. Proline and soluble sugars were increased under salt stress, while membrane stability index and relative water content decreased. Interaction between salt stress and foliar treatments showed that the highest increase in chl. b, carotenoid and proline were recorded in 5 dS m^-1 NaCl and proline plus salicylic acid with increase of 93, 53 and 143% as compared to the control, respectively. Membrane stability index and relative water content were decreased 63 and 38% as compared to the control, respectively. So, foliar application of 10 mM proline with 3 mM salicylic acid on physiological parameters of soybean was the best treatment to mitigate the detrimental effects of salt stress. So, proline function as compatible solute in osmotic adjustment and salicylic acid with the protective role through physiological reactions under salt stress.

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The fig, a sub-tropical crop, consumes as a table fruit as well as a dry product. Since, salinity is the serious concern of fig production, during 2016-2018, seven fig cultivars (‘Sabzʼ, ‘Siyahʼ, ‘Shah Anjirʼ, ‘Atabakiʼ, ‘Kashkiʼ, ‘Matiʼ and ‘Barʼ) were subjected to saline water (0.5, 2, 4, 6, 8 and 10 dSm^-1). Then, potein, proline, photosynthetic pigments, superoxide dismutase, catalase, guaiacol peroxidase and ascorbate peroxidase content were compared to introduce the most salt-tolerant cultivar. The results indicated, salinity caused an increase in total protein, proline and activity of antioxidant enzymes, but a decrease in chlorophyll (a, b, total) and carotenoids pigments. According to the results “Siyah” and “Sabz” cultivars were the most salt-tolerant and “Shah Anjir” was the most salt -sensitive cultivar. The ‘Atabakiʼ, ‘Kashkiʼ, ‘Matiʼ and ‘Bar anjirʼ were placed between them

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In order to investigate the role of Piriformospora indica endophyte fungi on some vegetative, physiological and morphological parameters along with antioxidant activity of stevia (Stevia rebaudiana) under cadmium (Cd) stress, an in vitro experiment was conducted. Experiment arranged in completely randomized design with three replicates. Treatments were five levels of Cd (0, 5, 10, 15 and 20 mg/L from cadmium chloride source) and two levels of fungi inoculation (including control and inoculation with P. indica). After 30 days, some growth characteristics, photosynthetic pigments, antioxidant enzymes activity, electrolyte leakage and soluble protein were measured. Regression analysis indicated that among vegetative dry weights, stem dry weight in uninoculated plants showed the maximum sensitivity (76%) to Cd concentration gradients. Fungi inoculation, however, markedly improved root dry weight up to 57%. Among morphological parameters, leaf area showed the highest reduction when Cd increased in the growing medium. By contrast, where P. indica was inoculated, green leaf percentage (51% reduction) was the most tolerant parameter. In terms of photosynthetic pigments, fungi inoculation could ameliorate reduction of carotenoid and chlorophyll a/b contents from 77 and 37 to 40 and 11%, respectively. In conclusion, results of the present study indicated that P. indica inoculation particularly at lower Cd concentrations could relatively improve stevia tolerance throughout decreasing H₂O₂ accumulation and enhancing photosynthetic pigments.

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Nitrogen is the first nutrient element that has a shortage in saline areas. Therefore, the correct management of nitrogen fertilizers is a suitable strategy to increase plant tolerance to salinity stress. This experiment was carried out in a completely randomized design in a factorial experiment on of Isfahan University of Technology, with three replication in 2017. Salinity stress was applied at four levels of 0, 2, 6 and 10 dS/m NaCl and nitrogen at four levels of 0, 50, 100 and 150 kg.ha^-1. Result showed the amount of photosynthetic pigments increased with nitrogen application under salt stress conditions. The highest total chlorophyll content was related to control treatment and 2 dS/m of salinity treatment both under 150 kg N.ha^-1, which was 18.20 and 17.63 mg/g leaf fresh weight respectively. Result of interaction salt and nitrogen showed highest sodium concentration and Na⁺/K⁺ and Na⁺/Ca²⁺ ratios were related to 10 dS/m salinity and no nitrogen application, which was respectively 342, 546 and 763% higher than the control treatment, while the highest amount of calcium was related to non-stress treatment and 150 kg N.ha^-1. The interaction between salinity and nitrogen levels showed that the highest height was related to salinity treatment 2 dS/m and consumption of 100 kg N.ha^-1, which increased 65% compared to the control. The highest area and number of leaves per plant were related to non-stress treatment and 150 kg.ha^-1 nitrogen which was 56% and 60% higher than the control treatment, respectively. The highest shoot dry weight was related to non-stress treatment and 50 kg.ha^-1 nitrogen. The highest leaf mucilage was related to non-stress treatment and consumption of 150 kg N.ha^-1, which increased 171% more than control treatment. From the results of this study, it can be concluded that shoot dry weight and leaf mucilage weight decreased significantly under salinity increasing. At least partly was due to the toxic effects of chlorine and sodium ions because such changes impair the photosynthetic activity of the plant, resulting in a decrease in dry weight and leaf mucilage; However, the use of nitrogen fertilizer up to 100 kg.ha^-1 can reduce the negative effects of salinity stress.
 

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Proline is an amino acid with a crucial role in ameliorating environmental stresses, including drought. In order to study the effect of external proline on the response of fennel to drought stress, three fennel genotypes (namely Urmia, Shiraz, and Kerman) were exposed to two levels of irrigation, i.e. control (34-45% of maximum allowable depletion in soil water) and drought (75-85% of maximum allowable depletion in soil water) and two levels of foliar-applied proline (0 and 20 mM) in a 4-replicate factorial randomized complete block pot experiment. Drought led to significant decreases in chlorophyll (Chl) and carotenoids (Cars) concentrations, leaf relative water content (RWC), ascorbate peroxidase (APX) and peroxidase (POX) activities, leaf water potential (ѱ_w), plant dry mass (DM) and seed weight and significant increases in leaf proline and polyphenols concentrations, and catalase (CAT) activity. Foliar-applied proline resulted in significant increases in membrane stability index (MSI), RWC, ѱ_w, proline and polyphenols concentrations, APX activity, plant DM and seed weight but it led to significant decreases in CAT and POX activities. Genotype Urmia out-numbered the remaining genotypes in terms of Chl and Cars concentrations, MSI, CAT and APX activities. There were significant correlations between leaf proline concentration and plant DM and seed weight under drought condition. Foliar-applied proline affected Chl and Cars differently in the drought-stressed and non-stressed plants. Furthermore, it affected plant seed weight in a genotype-dependent manner, as evidenced by 150% and 110% increases in Urmia and Shiraz and a 42.5% decrease in Kerman. It may be concluded that drought suppresses fennel growth, but foliar-applied proline is potent to mitigate the depression through increasing the leaf Chl, Cars, proline, and polyphenols concentrations, RWC and certain antioxidative enzymes activities in genotypes such as Urmia and Shiraz.

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Licorice (Glycyrrhiza glabra L.), is one of the herbal medicines and glycyrrhizin is the most important chemical content through compounds exiting in licorice, which is 50 times sweeter than sucrose. Drought stress is one of the limiting factors of growth and development of the plants having negative impacts on morphological and physiological processes in plants. In order to investigate the effects of different levels of drought stress on some growth, physiological and biochemical characteristics of two genotypes of licorice, an experiment was conducted in field as a factorial experiment based on randomized complete block design with three replications. Experimental treatments included different levels of drought stress (control, 10, 20 and 30 days) and different genotypes of licorice (Chaharmahal_Bakhtiari and Ilam). The studied parameters such as: dry weights roots and fresh weights of shoot, relative water content (RWC), chlorophyll a (Chlα), chlorophyll b (Chlb), total chlorophyll, carotenoid, antioxidant activity, total phenol content, ascorbate peroxidase (ASP) and glycyrrhizin content were investigated in this study. The results showed that, the root dry weight, shoot fresh weights, RWC, Chlα, Chlb, total chlorophyll and carotenoids were decreased significantly under drought stress. The highest antioxidant and ASP activity 88.85% and 4/4 absorbance changes in mg of protein, respectively, were recorded in Ilam genotype in intense stress. Also, the highest amount of total phenol was observed in Ilam genotype in moderate stress (59 mg Gallic acid per 100 g) and the maximum content of glycyrrhizin was observed in genotype of Chaharmahal and Bakhtiari genotype under mild stress (2.97%). In general, the morphological traits and antioxidant properties of Ilam genotype were higher than Chaharmahal_Bakhtiari. However, in terms of photosynthetic pigments and glycyrrhizin content, genotype of Chaharmahal_Bakhtiari was higher than Ilam. It seems totally, regarding to the antioxidant content the Ilam genotype is superior to Chaharmahal_Bakhtiari in drought tolerant.

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Drought stress is one of the most important abiotic stresses that exerts harmful effects on productivity of crops, including oilseed crops. Salicylic acid is one of the plant growth regulators that plays a key role in plant resistance against environmental stresses, including drought. Therefore, a factorial randomized complete block pot experiment with three replications was designed to assess the effect of salicylic acid (two levels of 0 and 0.6 mM) on three sesame genotypes (Yekta, Shiraz and Nazetakshakheh) in the presence of three levels of irrigation (irrigation after 60, 70 and 80% of available soil water depletion) in the greenhouses of Isfahan University of Technology, Isfahan, Iran in 2016. Results showed that chlorophyll a, b and total concentrations, number of capsules per plant, number of seeds per capsule and seed weight per plant decreased in stressed plants, whereas carotenoids concentration and activity of antioxidants enzymes including catalase, ascorbate peroxidase, and peroxidase increased under stress conditions. Application of 0.6 mM salicylic acid improved the measured traits under both control and stress conditions. Salicylic acid improved the tolerance of sesame against drought. With increasing drought levels (irrigation after 70 and 80% of available soil water depletion), Yekta and Shiraz genotypes showed less decrease in measured traits in pot experiment.

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In order to evaluate the effect of deficit irrigation and different types of potassium fertilizers on improving the photosynthetic pigments content and chlorophyll florescence parameters in rice (cv. Tarom Hashemi), two field experiments were conducted in the Rice Research Institute (Amol) and model farm located in Savadkouh in a split plot based randomized complete block design with three replicates. Treatments were different irrigation methods at two levels (flooding, flooding after falling water depth under 10 cm of soil surface) and nine levels of potassium fertilizers application (including potassium sulphate, potassium chloride and biofertilizer). Chlorophyll a, b and a+b contents, maximum fluorescence, variable fluorescence, electron transport rate of photosystem II (ETR) and grain yield significantly decreased under deficit irrigation in both two stations as compared to flooding irrigation treatment. Current research demonstrated a positive effect of potassium fertilizer application through significant increment in chlorophyll content and non-photochemical quenching (NPQ) index in limited irrigation condition. The highest amounts of grain yield (4945 and 4770 kg ha^-1 in the Amol and Savadkouh stations, respectively) were recorded when 50% of potassium sulfate and 50% of potassium chloride were applied as a basal and top dressing, respectively. According to the significant and positive correlation between grain yield and chlorophyll a and a+b content, maximum potential quantum efficiency of photosystem II (Fv/Fm) and ETR, it can be conclude that the application of 50% of potassium sulfate as a basal and 50% of potassium chloride as a top dressing was the most effective treatment in term of the studied traits, especially in the limited irrigation condition.