Salinity stress
Roohollah Nikfekr; Seyed Kamal Kazemitabar; GholamAli Ranjbar; Seyed HamidReza Hashemi-Petroudi; Pooyan Mehraban Joubani
Abstract
IntroductionSesame is one of the oldest products known to man to date. Sesame was a valuable crop in the ancient world due to its drought resistance, ease of oil extraction from seeds and oil stability. Iran is one of the arid and semi-arid regions of the world in terms of climate. In these areas, low ...
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IntroductionSesame is one of the oldest products known to man to date. Sesame was a valuable crop in the ancient world due to its drought resistance, ease of oil extraction from seeds and oil stability. Iran is one of the arid and semi-arid regions of the world in terms of climate. In these areas, low and scattered rainfall and high evaporation usually cause the accumulation of salts in the surface layer of the soil. Therefore, the salinity of soil and irrigation water causes significant morphological, physiological and chemical changes. Excess salt, that is, more than plants need limits crop growth and production and can lead to plant death.Materials and methodsIn this experiment, 20 sesame genotypes were grown in greenhouses. The experiment was performed as a factorial in a completely randomized design with three replications. 75 mM sodium chloride was dissolved per liter of water and the pots were irrigated with saltwater. Percent morphological traits loss index (PML) was calculated.Results and discussionAccording to the results of analysis of variance and comparison of the mean interaction of cultivar × stress in all studied traits were significant. American and Yellow- White cultivars with 17927 and 14.07 g, respectively, the highest and 714 and Dezful with 2.43 and 2.07 g, respectively, the lowest yield under normal conditions, and Oltan and American cultivars, respectively, with an average of 963 8.8 and 7.34 g had the highest and Darab 1 and Dezful had the lowest yield under stress conditions with 0.92 and 0.71 g, respectively. In this study, clustering method was used to group and separate useful (high yield) and susceptible (low yield) genotypes based on different traits. The results showed that the studied genotypes were grouped based on morphological traits and yield reduction percentage index using standard data. The studied genotypes were divided into 3 groups. In the first group, Oltan, American, Chinese, Dashtestan 2, 369 and 418 genotypes with the highest yield among the genotypes were studied. The second group included Darab 1, 730 and Dezful genotypes and the third group included other genotypes. In the first group, it is desirable to distinguish high-yield genotypes with desirable traits and the lowest percentage of yield reduction under salinity stress conditions from other genotypes.ConclusionsThe results of this experiment showed that there is a favorable variation among the study population, especially a significant difference was observed between the performance of genotypes in both normal environmental conditions and salinity stress. Correlation analysis of traits showed that under normal conditions, number of seeds per plant, number of capsules per plant and 100-seed weight, and under salinity stress, number of seeds per plant, number of capsules per plant and single plant weight had the highest correlation with yield. In this experiment, the best salinity tolerant lines were Oltan, American, Chinese, Dashtestan 2, 369 and 418 genotypes. It is noteworthy that these genotypes had a more stable performance than others in both conditions, so they have stress tolerance genes and can be considered in future studies. Also Darab 1, 730 and Dezful genotypes were the most sensitive genotypes to salinity stress in this experiment.
Drought stress
Milad Soltanieh; Daryush Talei; Parisa Nejatkhah
Abstract
IntroductionDrought stress is one of the environmental factors that affects the growth, yield and yield components of plants. Nitrogen and methanol play a key role in plant structure and metabolism. Black cumin (Nigella sativa L.) is one of the medicinal plants in the family of Ranunculaceae. The seed ...
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IntroductionDrought stress is one of the environmental factors that affects the growth, yield and yield components of plants. Nitrogen and methanol play a key role in plant structure and metabolism. Black cumin (Nigella sativa L.) is one of the medicinal plants in the family of Ranunculaceae. The seed of Nigella sativa plant has been used since long to protect health and combat different diseases and its frequent application in the pharmaceutical industry. The plant is cultivated in different parts of Europe and Asia including Iran. The purpose of this study was to investigate the responses of growth indices and yield of the black cumin to nitrogen and methanol under water stress conditions.Materials and methodsHealthy seeds of black cumin were provided from Medicinal Plants Research Center, Shahed University. The experiment was a split split-plots study based on randomized complete block design with three factors and three replicates. The experiments were conducted in the farm of Zanjan University, Faculty of Agriculture (36° 41’ N latitude, 48°27’ E longitude, and altitude of 1620 m) during the year farming in 2019-2020. The factors were drought stress with 4 levels (control irrigation, irrigation at 80% soil capacity, irrigation at 60% soil capacity, irrigation at 40% soil capacity) as the main plots, nitrogen with 4 levels (control, 30, 60 and 90 kg per hectare) as the sub-plots and methanol with 3 levels (0, 10 and 30%) as the sub-sub-plots. In fact, for each level of methanol, two g l-1 glycine and one g l-1 tetrahydrofolate as catalysts and one g l-1 tween80 were added to increase the adhesion of methanol solution. In both areas, soil preparation, including plowing, leveling and paving was performed before planting. Black cumin seeds were weighed in the amount of 4 g and the seed was evenly distributed.At the time of complete ripening, after removing the marginal effects, a random sample was selected from each plot and the plant height, root length crop growth rate (CGR) were measured.Also, after the final ripening, sampling was done to determine the grain yield after removing the marginal effects and one square meter was taken from each experimental unit and the number of plants per square meter was counted and then the seeds were separated from the plants and weighed and then reported in kg ha-1. To measure yield components (number of capsules per plant, number of seeds per capsule and 1000-seed weight) at the time of harvest, 5 plants were randomly selected from each experimental unit and the number of capsules was counted and then the seeds were taken out of the capsules. To measure the weight of 1000 seeds from the harvested seeds related to grain yield, three thousand samples of seeds were counted and then weighed and their mean as 1000 seeds weight and were used for data analysis.Results and discussionThe results showed that with increasing irrigation stress, plant growth indices and yield decreased, while with increasing nitrogen and methanol concentrations, growth indices and yield increased. In total, application of 10% methanol and 30 kg ha-1 nitrogen increased root length plant height by 9 and 16% compared to the control treatment. The results showed that the triple interaction of control irrigation, application of 30 kg ha-1 nitrogen and 10% methanol increased crop growth rate by 17.44% compared to control treatment. The highest grain yield by interaction of without irrigation stress and application of 90 kg ha-1 nitrogen and application of 10 percent methanol in the amount of 715.40 g were observed. Application of high levels of nitrogen and methanol under severe stress reduced grain yield, while application of lower levels of nitrogen (30 kg ha-1) and methanol (10%) increased grain yield, and the triple interaction of non-stress irrigation, application of 90 kg ha-1 nitrogen and 10% methanol caused a significant increase in grain yield (3.6%).ConclusionThe results showed that severe drought stress by reducing plant height, root length, crop growth rate, number of seeds per capsule and number of capsules per plant could reduce grain yield in black cumin and methanol application, especially at the level of 30%, with a positive effect on source strength (leaf area index) and reservoir strength (number and size of seeds) as well as root length, was able to increase black seed grain yield under water stress. The maximum crop growth length was obtained by triple interaction of control irrigation, application of 30 kg ha-1 nitrogen and 10% methanol foliar application at 35.31 g m-2 day and according to the importance and economic value of black cumin plant in the pharmaceutical industry The use of this treatment is recommended for producers of this plant.
Salinity stress
Mojdeh Akbarzadeh Lelekami; Mohammad Hadi Pahlavani; Khalil Zaynali Nezhad; Keyvan Mahdavi Mashaki; Andreas P.M. Weber; Dominik Brilhaus
Abstract
IntroductionSalinity as one of the major abiotic stresses influences plant growth and development. Among the cereal, rice is the most sensitive to salinity stress, with 30 mmol NaCl already strongly reducing the growth and yield of rice plants. Over the past few decades, significant efforts have been ...
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IntroductionSalinity as one of the major abiotic stresses influences plant growth and development. Among the cereal, rice is the most sensitive to salinity stress, with 30 mmol NaCl already strongly reducing the growth and yield of rice plants. Over the past few decades, significant efforts have been made worldwide to understand mechanisms of salinity tolerance and to breed salt-tolerant varieties in rice. Plants respond to salt stress through perceiving and transducing the osmotic and ion signals to cell interiors, followed by modification of cellular characteristics.So far, no specific sensor or receptor for Na+ has been identified in plants. However, the salt overly sensitive (SOS) signaling pathway and calcineurin B-like (CBL)/CBL-interacting kinase (CIPK) pathway has been well characterized in Arabidopsis. Salt-induced elevation in cytosolic Ca2+ activates the SOS2-SOS3 protein kinase complex, which phosphorylates and stimulates the activity of SOS1, a plasma membrane Na+/H+ antiporter. In rice, the OsSOS1, OsSOS2/OsCIPK24 and OsSOS3/OsCBL4 genes have been isolated and the function and relationship between them investigated. Among them, OsCIPK24 and OsCBL4 act in concert to activate OsSOS1. In this research, we used RNA-seq approach to dissect signaling pathway in response to salinity stress using salt-tolerant and sensitive rice cultivars.Materials and methodsThe seeds of two rice (Oryza sativa L. ssp. Indica) genotypes with different salinity tolerance were obtained from International Rice Research Institute (IRRI) in Philippines. The plants were grown hydroponically in the greenhouse of Heinrich-Heine-University (HHU), Düsseldorf, Germany. The two-week old seedlings were exposed to 150 mM (15 dSm-1) NaCl salinity. The root and shoot samples were harvested at 6h and 54h post-treatment in three biological replications. 48 samples were sequenced by Illumina platform and the raw filtered reads were mapped on rice reference genome. Tuxedo instruction was applied to identifying the differentially expressed genes (DEGs). MapMan software was used to identify the genes involved in signaling pathwayResults and discussionIn RNA-Seq analysis, 48 samples were sequenced by Illumina platform and 15483 differentially expressed genes (DEGs) were identified. Out of the DEGs (from the comparison between the cultivars), 525 and 1472 genes were salt-specific in 6 and 54h time points in roots respectively. Out of the salt-specific DEGs in shoots, 635 and 606 genes were in 6 and 54h respectively. MapMan pathway analysis detected 91 genes in signaling pathway. Out of the genes, 27 genes showed high expression. Out of the genes, 21 genes showed more expression in tolerant cultivar CSR28 compared to sensitive cultivar IR28. The most difference between the cultivars was observed in roots after 54h of salt treatment suggesting the critical role of roots in salt tolerance induction. Receptor like kinase (RLK) proteins played the most important role among the identified signaling genes. Several important genes involved in major signaling processes such as OsSIK1, OsSAPK4, OsCIPK05, OsCIPK14, OsCBL4 and OsPP2C1 were identified in this research.ConclusionSalt-tolerant cultivars use better signaling pathways to sensing of stress and having the stronger osmotic and ionic reactions to cope with salinity stress. In the present research, huge number of differentially expressed genes generated using rice tolerant cultivar CSR28 and sensitive cultivar IR28 at 6 and 54h sampling times by RNA-Seq method. The comparison of the cultivars at specific salt stress showed that 91 genes (including 27 high expressed genes) were involved in signaling pathway. Kinase proteins played the most important role among the signaling pathway genes. The important genes identified in this research can be applied in the selecting and developing of salt-tolerant rice cultivars.AcknowledgementsWe appreciate the International Rice Research Institute (IRRI) for providing the seeds. We also acknowledge the excellent technical assistance of Gorgan University of Agricultural Sciences and Natural Resources (GAU), Gorgan, Iran and Heinrich-Heine-University (HHU), Düsseldorf, Germany.
Drought stress
Abbas Soleimanifard; Mani Mojaddam; Sharam Lack; Mojtaba Alavifazel
Abstract
IntroductionSafflower is an oilseed plant tolerant to water deficit, and have an important role in oil production. Drought stress is the most important factor limiting crop yields in many parts of the world, including Iran. Nitrogen plays a key role in plant growth and this role is highly related to ...
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IntroductionSafflower is an oilseed plant tolerant to water deficit, and have an important role in oil production. Drought stress is the most important factor limiting crop yields in many parts of the world, including Iran. Nitrogen plays a key role in plant growth and this role is highly related to the amount of water and how it is distributed. Bacteria of the genus Azotobacter are one of the most important growth-promoting bacteria in plants due to their abundance and extent of spread, which is able to improve the availability of nitrogen. In areas where most rainfall occurs in winter and early spring, crops will face water constraints at the end of the growing season. In such conditions, finding cultivars and lines that have good performance in non-stress and drought stress conditions and have a suitable response to Azotobacter and nitrogen fertilizer is of special importance.The aim of this experiment was to evaluate the response of safflower genotypes to the application of Azotobacter and nitrogen fertilizer under different moisture conditions.Materials and methodsThis experiment was carried out during two growing seasons (2015/2016 and 2016/2017), in Sarableh Agricultural Research Station, Ilam Province. The factorial scheme 4 × 6 experiment was performed in both years in a randomized complete block design with three replications under terminal drought stress and non-stress conditions. The distance between these two environments was considered to be 10 meters so that the humidity of the two adjacent environments did not affect each other. Experimental factors included seed inoculation with A. chroococcum using urea chemical fertilizer at four levels [without using any N fertilizer source (control), seed inoculation with A. chroococcumalso without use N fertilizer, seed inoculation with A. chroococcum + 50% N of urea fertilizer source, and 100% N of urea fertilizer source], and six safflower genotypes (312-S6-697, PI-401478, PI-253895, PI-306974, Padideh, and Sina).After harvesting and determining grain yield in both experimental conditions, stress tolerance indices including stress sensitivity index (SSI), mean productivity (MP), tolerance (TOL), geometric mean yield (GMP), stress tolerance index (STI) and Modified stress tolerance indices (MSTI) were calculated. Statistical calculations of analysis of variance and mean comparisons were performed using SAS 9.1 software. STATGRAPH software was used to principal component analysis and drawing biplot diagrams.Results and discussionThe results showed that among the nitrogen source treatments, the highest percentage of grain yield reduction with 48% in drought stress conditions compared to non-stress conditions was related to the application of 100% nitrogen chemical fertilizer. This result shows that in drought stress conditions, the application of 100% nitrogen fertilizer due to the increase of biological substances, causes an imbalance between the roots and plant aerial parts in water absorption and water loss through transpiration by aerial organs, which in Extremely serious damage to the economic sector of the plant.Azotobacter inoculation + 50% nitrogen fertilizer application had the highest mean productivity index and the lowest stress sensitivity index among nitrogen source treatments, although it was not significantly different from other nitrogen source treatments. These results indicate that the use of Azotobacter in combination with the application of 50% nitrogen fertilizer reduces the damage caused by drought stress in safflower. Sina cultivar was the most tolerant genotype under drought stress under Azotobacter inoculation and 100% nitrogen fertilizer application. In conditions of inoculation with Azotobacter + 50% of nitrogen fertilizer application, Sina and Padideh cultivars are located in the area of high production potential and low drought sensitivity in the vicinity of vectors related to drought tolerance indicesConclusionSina cultivar in inoculation treatment with Azotobacter and consumption of 100% nitrogen fertilizer, Padideh cultivar in addition to Sina cultivar in combined application of Azotobacter + 50% nitrogen fertilizer had the highest tolerance to terminal drought stress; Therefore, in selecting drought tolerant genotypes, special attention should be paid to nitrogen source factor.
Salinity stress
Roohollah Shamloo-Dashtpagerdi; Sirus Tahmasebi
Abstract
IntroductionSoil and water salinity has significantly reduced crop yields and threatened human food security worldwide. Understanding the molecular basis of how crop plants receive and respond to salinity and identifying the main components of their stress tolerance are essential for developing tolerant ...
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IntroductionSoil and water salinity has significantly reduced crop yields and threatened human food security worldwide. Understanding the molecular basis of how crop plants receive and respond to salinity and identifying the main components of their stress tolerance are essential for developing tolerant plants through genetic manipulation. Today, functional genomics methods such as transcriptomics, proteomics, and metabolomics have revolutionised the study of plant stress response and facilitated the identification of important pathways and components governing stress tolerance. For example, the production and analysis of EST sequences, RNA microarray, and RNA-sequencing technology (RNA-seq) have made it possible to study and identify gene transcripts in genome-wide stress response networks. Accordingly, this study aimed to analyse the transcript of forage turnip (Brassica rapa L.) under salinity stress, determine the functional orientation of the genome, and identify the important components and genes involved in salinity tolerance.Materials and methodsTwo Expressed Sequenced Tags (ESTs) libraries of forage turnip under non-stress and salinity stress conditions were analysed using bioinformatic and statistical methods. Non-stress and salinity stress libraries had 8408 and 6894 sequences, respectively. After sequences trimming, the genome functional orientation of forage turnip in response to salinity stress was determined based on Fisher's exact test using the DAVID tool. Differentially expressed genes (DEGs) were assigned using the Audio and Claverie statistical test (AC test) implemented in the IDEG6 tool, at a significance level of 5%. Based on Fisher's exact test, a hierarchical gene network among DEGs was predicted. Then, gene network topology analysis was performed using the NetworkAnalyzer plugin in Cytoscape 4.3. One gene was identified as an important gene (Hub gene) based on gene network topology analysis. In a greenhouse experiment using a tolerant genotype and a susceptible genotype of forage turnip, the expression profile of the identified important gene along with some traits related to the plant antioxidant system, including anthocyanin content, antioxidant enzymes activity, and malondialdehyde content, were evaluated in response to different salinity time points. Finally, the relationship among the changes in gene expression, evaluated traits, and salinity tolerance was determined using Correspondence Analysis (CA).Results and discussionPre-processing of 8408 EST sequences of the non-stress library resulted in 8,403 high-quality sequences. Also, out of 6894 EST sequences from the salinity stress library, 6894 high-quality sequences were obtained. BlastX against Arabidopsis proteins showed that 8075 (96.1%) of the non-stress EST sequences had at least one specific hit. 6597 (95.7%) of the EST sequences of the salinity stress library also had at least one specific hit in BlastX. Based on Fisher's exact test, 15 functional groups were significantly (FDR≤0.01) more active in salinity stress conditions than in non-stress conditions. These results clearly showed that under salinity conditions, the genome functional activity of forage turnip was oriented towards response to stresses, especially oxidative stresses, response to internal inductions such as plant hormones, control of metabolic activities, and photosynthetic reactions. Audic and Claverie’s statistical test showed 344 genes were differentially expressed in response to salinity stress; among them, 242 genes were upregulated, and 102 genes were downregulated. The predicted gene network indicated a complex relationship among DEGs, regulatory molecules (especially melatonin and plant hormones), and downstream responsive pathways. Among identified DEGs, the gene encoding transcription factor ZAT6 was assigned as an important gene in the salinity response gene network. The expression profile of the ZAT6 gene, quantity of anthocyanin, the activity of antioxidant enzymes and content of malondialdehyde were significantly different between the two studied genotypes. ZAT6 was significantly more expressed in the stress-tolerant genotype than the stress-susceptible genotype at all time points. In addition, the antioxidant system of the tolerant genotype was more potent than the susceptible genotype. Also, results revealed a significant relationship between the expression profile of ZAT6 and evaluated traits in the context of salinity tolerance. Based on the results, changes in ZAT6 gene expression are directly or indirectly involved in regulating forage turnip plant responses to salinity stress, especially through the control of evaluated traits.ConclusionTranscriptome study clarified some of the molecular bases of the forage turnip response to salinity stress. Accordingly, it seems that the gene encoding the ZAT6 transcription factor plays an important role(s) in the salinity stress tolerance of forage turnip. There was a significant relationship between high expression levels of this gene and enhanced antioxidant activities, which could confirm the hypothesis. However, further studies are needed to assign detailed functions of ZAT6, particularly the association of this gene with the regulatory pathway of melatonin as a major regulatory molecule in plants. This can be an effective starting point for further studies.AcknowledgmentsWe would like to thank the support of the Higher Education Center of Eghlid for this research project.
Drought stress
Hamid Dehghanzadeh; zohrab Adavi
Abstract
IntroductionWheat is a major staple food crop in the world. Although all abiotic stresses adversely affect the wheat growth and production, water scarcity imposes the most severe effects on this crop. Drought stress is also believed to affect the uptake, transport and accumulation of key inorganic nutrients ...
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IntroductionWheat is a major staple food crop in the world. Although all abiotic stresses adversely affect the wheat growth and production, water scarcity imposes the most severe effects on this crop. Drought stress is also believed to affect the uptake, transport and accumulation of key inorganic nutrients in plants. Silicon occurs abundantly in soils, but in the field of plant growth the other inorganic elements for plant growth are more important than Silicon. However, Silicon plays an effective role in plants under stressful conditions. Silicon entails useful effects in plants under water-deficit treatments, with respect to drought-induced regulation of metabolic processes and water relations. Of several plant growth regulators, Cycocel (CCC) is believed to be very effective in masking the adverse effects of different abiotic and biotic stresses on crops as well as being an essential component of the signal-transduction pathways operating in plants exposed to environmental cues including drought stress. Exogenously applied CCC is believed to affect absorption and transport of nutrients, stomata regulation, growth and photosynthetic rate, chlorophyll synthesis and transpiration. The literature has little information on the role of Silicon and CCC applied in combination in alleviating drought-induced injurious effects on plants. Therefore, in the present study, we appraised the effects of exogenous Silicon and CCC applied individually or in combination on wheat growth and grain yield under water-deficit conditions.Materials and methodsThis study was carried out in Tiran province, Isfahan, Iran during 2018-2019, as a split-split plot design in randomized complete block with three replications. The main plots considered irrigation regimes (full irrigation and 40% field capacity irrigated), sub-plots considered Silicon and cycocel application (control, 3.6 g l-1 Silicon, 210 mg l-1 Cycocel, and 3.6 g l-1 Silicon + 210 mg l-1 Cycocel) and sub-sub plots considered two wheat cultivar (Sirvan and Chamran). All measurements based on fresh plant samples were done before the grain-filling stage. Measurements included relative water content, soluble sugars and soluble proteins; activities of peroxidase, ascorbate peroxidase, catalase, superoxide dismutase, levels of hydrogen peroxide, malondialdehyde, concentrations of Ca, K and Mg and leaf water potential. At maturity, yield and yield components were measured. Statistical analysis of data was performed using the MINITAB statistical software.Results and discussionDrought stress caused a considerable reduction in yield and yield components and relative water content of both cultivars. Application of Silicon and cycocel effectively improved these parameters in water-deficit treatments. Moreover, water-limited conditions markedly promoted the activities of key antioxidant enzymes including peroxidase, ascorbate peroxidase, catalase and superoxide dismutase, while enhancing the accumulation of soluble sugars, potassium, magnesium and calcium in leaf tissues. Application of Silicon and cycocel further enhanced the activities of the key antioxidant enzymes and accumulation of osmolytes, and decreased the levels of H2O2 and malondialdehyde in drought stressed plants. Synergistic effects of Silicon + cycocel application on yield and physiological parameters were apparent compared with Silicon or cycocel applied separately. Water-stress alleviation and yield improvement in the wheat cultivars by Silicon and cycocel application was attributable to partly improved osmotic adjustment and antioxidant activity as well as to more favorable water status under stress conditions.ConclusionFoliar application of Silicon, CCC and especially the combination Silicon + CCC, markedly improved grain yield and yield components of the two wheat cultivars under water-deficit. In Silicon, CCC and Silicon + CCC treatments, grain yield was 15.63%, 16.60% and 24.32% higher respectively, than with no foliar application under water stress in cv. Chamran, and 10.25%, 16.02% and 19.25% higher in cv. Sirvan. The results of the study highlight the role of Silicon and CCC application in regulating water-stress response of wheat, suggesting that Silicon and CCC are involved in physiological activities. These results showed positive effects of Silicon and CCC in terms of increased antioxidant activity as well as relative water content and leaf water potential. In addition, Silicon and CCC stimulated the active accumulation of some osmolytes in leaves of water-stressed wheat plants, which suggests enhanced osmoregulation ability. The synergistic effects of Silicon + CCC application on yield and physiological parameters were greater than of Silicon or CCC applied separately. Therefore, proper application of Silicon and CCC might result in increased production of wheat, particularly in dryland areas.
Drought stress
Arezoo Paravar; Saeideh Maleki Farahani; Alireza Rezazadeh
Abstract
IntroductionWater deficit is as one of the most ominous abiotic factors that limits the growth and yield of crops and reduced photosynthesis content (Askary et al., 2017). The common symptoms determined in plants after encountering water deficit include a hindrance to growth, a reduction in the rate ...
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IntroductionWater deficit is as one of the most ominous abiotic factors that limits the growth and yield of crops and reduced photosynthesis content (Askary et al., 2017). The common symptoms determined in plants after encountering water deficit include a hindrance to growth, a reduction in the rate of photosynthesis, an acceleration oxidative stress (Aalipour et al., 2020). A balanced nutrient concentration in the soil is known as another essential element for plant growth regulation (Taghizadeh et al. 2019). This can be supplied by the application of chemical fertilizers (nano iron chelate). Nano iron chelate fertilizer can also protect plants against water deficit stresses and improves photosynthesis and assimilates transportation to sinks and eventually amends grain yield and oil content (Moradbeygi et al., 2020). The aim of this study was to investigate the response of Dragon head (Lalelemantia iberica) and Lady's mantle (Lalelemantia royleana) to the application of nano-chelate fertilizer in different irrigation regimes.Materials and methodsThe field trial was conducted at the Research Farm of the Agricultural Faculty of Shahed University, Tehran, during the cropping season of 2018 and 2019. A split-factorial experiment was employed in a randomized complete block design (RCBD) with three replications. The main plot consisted of three-level of irrigation regime (30% (I30; without stress), 60% (I60; mild stress), and 90% (I90; sever stress) depletion of available water resource). The sub plots were factorial combination nano-iron chelate (without fertilizer and nano-iron chelate) and plant species of Lallemantia (L.iberica and L. royleana).Results and discussionBy increasing water deficit reduced, chlorophyll a and b, CAT and APXs enzyme activity, plant height, root length, seed yield, content of mucilage and oil. The reduction of plant growth parameters and seed yield of both species Lallemantia may be due to extended irrigation intervals which caused decline in Chl concentration, stomata closure, and decreased CO2 uptake for photosynthesis (Paravar et al., 2021). Our results showed that the highest chlorophyll a and b, CAT and APXs enzyme activity, plant height, root length, seed yield, content of mucilage and oil was obtained at 60% available water soil of depletion (moderate drought stress). The application nano-iron chelate in all cases mitigated the negative effects of water deficit stress on chlorophyll a and b, CAT and APXs enzyme activity, plant height, root length, seed yield, content of mucilage and oil. Increasing in growth parameters and seed yield under drought stress of Lallemantia species under application of nano-iron chelate condition in drought stress may be due to the role of iron the chlorophyll structure and plant photosynthesis system (Moradbeygi et al., 2020). Indeed application of nano-iron chelate by photosynthesis improvement and material production in the plant causes the increasing growth and yield. (Iqbal and Umar, 2019). In addition, in this study observed nano-iron chalet application played the important role on the increasing of CAT and APXs enzyme activity under drought stress. It has been reported that micronutrients such as iron has a structural role in some enzyme such as CAT and APXs (Moradbeygi et al., 2020). Higher seed yield and seed oil L.iberica than L.royleana under application nano-iron chelate and different levels of irrigation regimes may be due to the increasing chlorophyll a and b (Paravar et al., 2022). Compared with L.iberica, the greater CAT and APXs enzyme activity in L.royleana is probably due to the mucilage around roots of L.royleana that has caused the reduction of oxidative stress (Paravar et al., 2021).ConclusionTherefore, in general in this research, it can be concluded that under water deficit stress conditions, we can reduce damages from water deficit stress in both species of Lallemantia with careful irrigation management (using an irrigation regime of 60% available water soil of depletion) and application nano-iro chelate.AcknowledgmentsWe kindly acknowledge the Shahed University of Tehran for their support of this research.
Drought stress
Ahmad Majidi-Mehr; Mohammad hadi Pahlavani; Khalil Zeinali-Nezhad; Rahmatollah Karimizaded; Andeas Borner
Abstract
IntroductionCrop yield products reduction due to abiotic stress is estimated at 51 to 82%. Most plants are exposed to environmental stresses, and water deficit is one of the most important non-abiotic stresses in limiting and producing crops around the world, especially in arid and semi-arid regions. ...
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IntroductionCrop yield products reduction due to abiotic stress is estimated at 51 to 82%. Most plants are exposed to environmental stresses, and water deficit is one of the most important non-abiotic stresses in limiting and producing crops around the world, especially in arid and semi-arid regions. Plants have developed various strategies to cope with water deficit stress, including morpho-physiological and biochemical.Wheat is one of the most important crops in the world, which in 2020 had the highest area under cultivation at the rate of 221.33 million hectares (with a total production of 766.03 million tons) worldwide. In the same year in Iran, the area under wheat cultivation was 6.70 million hectares and its production was 16.75 million tons.Materials and methodsThe research was performed in research farm of Rainfed Agricultural Research Station Gachsaran, Iran, over 2020-2021 cropping years. In this study, 100 lines obtained from the landrace bread wheat of different origins from several continents and several countries were studied. The experiment was performed in a simple lattice design 10×10 with two replications and separately in two environmental conditions of stress and non-stress. The operation planting is done in January after conventional tillage implementation of the area by hand. The source of moisture supply for both rain fed (water deficit stress) and irrigation (no stress) test conditions was rainfall and sprinkler irrigation before the phonological stage of flowering (pollination (Zadocs scale 61)). Irrigation interruption was applied at the beginning of flowering in a stress environment (water deficit stress conditions) which continued until harvest, but the environment without stress in two times when wheat plants to early reproductive stage, flowering stages, and the beginning of grain filling (Grain paste stage (Zadocs scale 61-83)) Irrigation was performed. In this study, 16 morphological traits and grain yield were measured under both stress and non-stress conditions, including flag leaf length and width (cm), flag leaf pod length (cm), and flag leaf area (cm2), number of nodes and leaves per stem, internodes number, peduncle length (cm), plant height (cm), tiller number, fertile and infertile tillers of number, length of awn (cm), spike length (cm) and spike yield (g).Results and discussionThe results of the analysis of variance showed high and significant variability in both non-stress and deficit water stress. TRI 3492 was the most tolerant of geographical origin in Nepal and TRI 4549 had the lowest STI relative to deficit water stress of geographical origin in China. The highest and lowest heritability in stress conditions were related to plant height (98.02%) and the number of intermediate nodes (25.00%), respectively. The greatest decrease in heritability (66%) due to stress conditions was the leaf sheath length of the flag leaf. Among the traits studied in this study, flag leaf area with 31.41%, flag leaf length with 25.25% and grain yield with 23.53% had the highest percentage of stress reduction. The results of cluster analysis of the studied genotypes in both environmental conditions are in six separate and different groups so that the greatest difference in genetic distance and grain yield in both environmental conditions was observed between the first and sixth clusters.ConclusionUsing the genotypes of first cluster (TRI 403, TRI 4013, TRI 3981, TRI 10340, TRI 5262, TRI 4549, TRI 2513, TRI 2656, TRI 3477, TRI 3242, TRI 3526, TRI 3513, TRI 4116 and TRI 4113) with 6TH cluster (TRI 10296, TRI657, TRI755, TRI752, TRI757, TRI 11020, TRI691, TRI 6129 and TRI754) Can be used in crossbreeding programs as well as genetic studies (such as recombinant populations and association mapping) and to increase the rate of heterosis used in water-deficit stress conditions.
Drought stress
Mina Shafiei; Ali Behpouri; Ehsan Bijanzadeh; Maryam Mirdoraghi
Abstract
IntroductionDue to the increase in world population and the need for food using traditional agricultural methods does not meet the needs of society. The Food and Agriculture Organization (FAO) predicts that by 2050, 60 percent more food production will be needed to feed the world's 9 billion population. ...
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IntroductionDue to the increase in world population and the need for food using traditional agricultural methods does not meet the needs of society. The Food and Agriculture Organization (FAO) predicts that by 2050, 60 percent more food production will be needed to feed the world's 9 billion population. This has concerned agroecologists to sustainable agriculture and encouraged them to do more research and design new sustainable agricultural systems. Therefore, the aim of this study was to examine different mixed cropping systems of cereals and evaluation of different drought tolerance indices using a mixture of winter cereals, wheat, barley and triticale and their response to end-of-season water stress in hot and dry ecological conditions.Materials and methodsIn order to investigate the grain yield and drought tolerance indices of mixed culture of different cereal genotypes to water stress in hot and dry ecological conditions, an experiment was conducted as split plot design based on a randomized complete block design with three replicates during 2017-2018 cropping year in College of Agriculture and Natural Resources of Darab, Shiraz University. In this experiment, the first factor was irrigation regime in two levels of normal irrigation and water stress and the second factor was ten cropping systems of genotypes (tall barley line EB-95-97, dwarf barley line EB-95-97, dwarf bread wheat line S-92-19, tall bread wheat cultivar Khalil and a cultivar of Triticale called Juanilo) which were grown as double and pure row culture. Double mixed crops included of: dwarf barley- tall barley (one row of dwarf barley + one row of tall barley), dwarf barley - triticale (one row of dwarf barley + one row of triticale), tall barley - triticale (one row of tall barley + one row of triticale), dwarf wheat - triticale (one row of dwarf wheat + one row of triticale) and tall wheat - triticale (one row of tall wheat + one row of triticale) in a 50:50 planting ratio and their pure cultivation.Results and discussionThe results of this experiment showed that the highest grain yield was obtained in tall wheat-triticale mixed culture with 9472 kg ha-1 under normal irrigation and the lowest grain yield was achieved in pure dwarf barley with 3934 kg ha-1 under water stress condition. The results of correlation analysis of drought indices showed that positive and significant correlations were observed between STI (r=0.858**), GMP (r=0.747*) and MP(r=0.801**) with grain yield under water stress conditions. Alos, positive correlation coefficients were observed between STI (r=0.884**), GMP (r=0.922*) and MP (r=0.932**) with grain yield under normal irrigation conditions. The highest SIIG index in this investigation was observed for dwarf barley-tall barley cropping system which had the minimum yield difference in normal and water stress conditions. 3D-graph of cropping systems using SIIG index indicated that cropping systems of pure tall wheat, pure dwarf wheat and tall barley+triticale mixture demonestraed the highest grain yield both in normal and water stress conditions.ConclusionTall wheat+Triticale mixed culture wheat cultivation system under normal irrigation conditions showed a 16% increase in yield compared to the tall wheat pure cultivation system, while it did not show a significant difference with the Triticale pure cultivation system. Some of the mixed cropping systems such as tall wheat + triticale mixed cropping systems produced higher yields that their pure cultivation systems. Alos, it was concluded that STI, GMP, MP and SIIG were the best drought stress indices to evaluate different cropping systems.
Drought stress
Farnaz Ahmadi Nouraldinvand; Raouf Seyed Sharifi; Seyed Ataollah Siadat; Razieh Khalilzadeh
Abstract
IntroductionDrought is assumed as one of the most severe abiotic stress factors limiting plant growth and crop production. Since in arid and semi-arid regions, some part of growth period of wheat is confronted with water limitation condition which can affect biochemical and physiological responses such ...
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IntroductionDrought is assumed as one of the most severe abiotic stress factors limiting plant growth and crop production. Since in arid and semi-arid regions, some part of growth period of wheat is confronted with water limitation condition which can affect biochemical and physiological responses such as changes in photosynthetic efficiency of PSII, chlorophyll content, and stomatal conductance. Application of bio fertilizers and silicon is one of the most important strategies for alleviation of drought stress effects. Bio fertilizers (plant growth promoting rhizobacteria or PGPR and mycorrhiza) can improve plant performance under non-stress and stress conditions. Thererfore, it seems that application of nano silicon and bio-fertilizer can improve wheat yield under water limitation conditions.Materials and methodsIn order to study the effects of biofertilizers and nanosilicon on phosphorus uptake, grain yield, and some physiological traits of wheat (Triticum aestivum L.) under withholding irrigation conditions, a factorial experiment was carried out at the research farm faculty of Agriculture and Natural Resources, University of Mohaghegh Ardabili, with three replications during 2018-2019. The area is 38° 15′ N latitude, 48° 15′ E longitude, and 1350 m above mean sea level. Climatically, the area is situated in the semi-arid temperate zone with a cold winter and moderate summer. Factors were included irrigation in three levels (full irrigation as control; moderate water limitation or withholding irrigation at 50% of the heading stage; severe water limitation or withholding irrigation at 50% of the booting stage) based on codes 55 and 43 of the BBCH scale; foliar application of nano silicon (foliar application with water as control, 30 and 60 mg.L-1) and bio-fertilizer (no application as control, mycorrhiza application, both application of flavobacterium and pseudomonas, both application of flavobacterium and pseudomonas with mycorrhiza). Mycorrhiza fungi (mosseae) was purchased from the Zist Fanavar Turan Corporation and soils were treated based on method of Gianinazzi et al. (2001). Psedomunas and flovobacterium were isolated from the rhizospheres of wheat by Research Institute of Soil and Water, Tehran, Iran. For inoculation, seeds were coated with gum Arabic as an adhesive and rolled into the suspension of bacteria until uniformly coated. The strains and cell densities of microorganisms used as PGPR in this experiment were 1×108 colony forming units (CFU). In this study, electrical conductivity, stomatal conductance, leaf fluorescence parameters, phosphorus of root and grain, relative water content, electrolyte leakage, anthocyanins and grain yield of wheat were investigated. Analysis of variance and mean comparisons were performed using SAS ver 9.1 computer software packages. The main effects and interactions were tested using the least significant difference (LSD) test at the 0.05 probability level.Results and discussionThe results showed that application of both flavobacterium and pseudomonas with mycorrhiza and foliar application of 60 mg.L-1 nano silicon under severe water limitation increased 84.32%, 49% and 49.52% of electrolyte leakage, electrical conductivity and minimum fluorescence (F0) respectively, and decreased root and grain phosphorus by 30.67 and 36.05% compared to full irrigation. The highest RWC (92.26%), stomatal conductance (58.86 mmol.m-2.s), anthocyanin (0.0274 µmol.g-1FW), Fm (860), and Fv/Fm (0.909) were obtained at foliar application of 60 mg.L-1 nano silicon, both applications of flavobacterium and pseudomonas with mycorrhiza under normal irrigation. Also, the highest grain yield was obtained with both flavobacterium and pseudomonas with mycorrhiza and foliar application of 30 mg.l-1 nano silicon under normal irrigation. According to the results of this study both the application of biofertilizers and nanosilicon can improve wheat grain yield under water limitation conditions by improving the physiological traits and also the uptake of phosphorus from the soil.ConclusionGenerally, it seems that application of bio fertilizers and nano silicon can be recommended as the proper method for increasing the physiological trait grain yield of wheat under water limitation conditions.
Drought stress
Hoseyn Safarpour; Ebrahim Khalilvand Behrouzyar; Mehrdad Yarnia; Bahram Mirshekari; Hassan Monirifar
Abstract
IntroductionBarley (Hordeum vulgare L.) It is one of the most important grains and belongs to the genus of wheat. It is cultivated in more than one hundred countries of the world as a profitable crop. Barley is mostly used for grain production, for animal feed and fermentation industries. Among the grains, ...
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IntroductionBarley (Hordeum vulgare L.) It is one of the most important grains and belongs to the genus of wheat. It is cultivated in more than one hundred countries of the world as a profitable crop. Barley is mostly used for grain production, for animal feed and fermentation industries. Among the grains, Barley had the highest production after wheat, rice and corn and accounts for nearly 91% of the world's grain production. In order to investigate the effects of urea foliar application on some physiological and agronomic characteristics of three barley cultivars under normal irrigation conditions and drought stress at the end of the season, a factorial experiment in the form of a randomized complete block design with three replications, during two years of cultivation 2017-2018 and 2018-2019 was carried out in the research farms of the Agricultural Research and Training Center of East Azerbaijan Province.Materials and methodsThis study is a two separate experiment with optimal irrigation and drought stress at the end of the season was done with similar plans. Irrigation was stopped at the stage of spike emergence. Urea foliar application levels include non-foliar application and once foliar application after spiking was determined as the first factor and barley cultivars as the second factor. Barley cultivars included Mahtab, Jolgeh and Makuei. Measured traits included; Grain yield, 1000-seed weight, flag-leaf area, flag-leaf chlorophyll content and flag-leaf proline.Results and discussionDrought stress reduces the value of all traits except flag-leaf proline and increased flag-leaf proline content in all cultivars. However, urea foliar application was able to mitigate the adverse effects of water stress. For the trait of grain yield, Mahtab cultivar with 4710.4 kg/ha at the control level and 5496.41 kg/ha at the level of urea foliar application, had the highest grain yield among cultivars under drought stress conditions. For the trait of 1000-seed weight, Mahtab cultivar with 34.15 g at the control level and 37.33 g at the level of urea foliar application, had the highest grain yield among cultivars under drought stress conditions. For the trait of flag-leaf area, Makuei cultivar with 13.95 cm2 at the control level and Jolgeh cultivar with 14.27 cm2 at the level of urea foliar application, had the highest flag-leaf area among cultivars under drought stress conditions. For the trait of flag-leaf chlorophyll, Makuei cultivar with 44.4 units at the control level and Jolgeh cultivar with 46.48 units at the level of urea foliar application had the highest flag-leaf chlorophyll among cultivars under drought stress conditions. For the trait of flag-leaf proline content, Mahtab cultivar with 5.4 units at the control level and 3.12 units at the level of urea foliar application had the highest flag-leaf proline content among cultivars under drought stress conditions. In general, Mahtab cultivar, compared to other cultivars, had a smaller decrease in the amount of studied traits under drought stress conditions that indicates its greater resistance and adaptation to water shortage stress.ConclusionIn general, the results showed that the cessation of irrigation at the stage of spike emergence in the used cultivars caused a significant reduction in the studied traits in both years of the experiment. However, urea foliar application was able to mitigate the adverse effects of water stress. So that the application of this element had a positive role in the studied traits barley cultivars especially in water shortage stress conditions. Study traits in used cultivars decreased in water shortage stress conditions that indicates the sensitivity of the studied cultivars to water shortage. Mahtab cultivar compared to other cultivars, was less reduction in the amount of studied traits under drought stress conditions. And also compared to other cultivars, was a further increase in flag-leaf proline content under drought stress conditions that indicates its greater resistance and adaptation to water shortage stress.
Drought stress
Safora Dehbalaei; Ali Ashraf Mehrabi; Abbas Maleki; Mohammad Mehdi Poursiahbidi
Abstract
IntroductionWheat (Triticum aestivum L.) is one of the main crops of the cereal family, which is widely cultivated in the world and brings energy and protein to human society. Drought is the most important non-living stress in crops and due to the decrease in annual rainfall and increase in temperature, ...
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IntroductionWheat (Triticum aestivum L.) is one of the main crops of the cereal family, which is widely cultivated in the world and brings energy and protein to human society. Drought is the most important non-living stress in crops and due to the decrease in annual rainfall and increase in temperature, production and cultivation of tolerant cultivars with high yield potential will be very important. While available water for agriculture is becoming more limited, the production of drought tolerant cultivars is very important and should be considered. The aim of this study was to analyze the stability of quantitative and qualitative yield and to analyze the stability of bread wheat genotypes in rainfed and irrigated planting conditions in the form of field farms in 3 crop years 2016-2017, 2017-1996 and 2017-17 in Sarableh Agricultural Research Station located in the province. Ilam was implemented.Materials and methodsThis research was conducted as two independent experiments, each in the form of a randomized complete block design with three replications. The first factor includes planting in irrigated and rainfed conditions. The second factor also included 20 wheat genotypes. In irrigated conditions, irrigation was done according to the needs of the plant (normal) and in another experiment, only atmospheric benzoate was sufficient. In this study, yield stability was measured based on drought resistance and its effective traits in different bread wheat genotypes and quantitative and qualitative yield. Data were analyzed using SAS software version 22 for combined analysis and comparison using the least significant difference test (LSD).Results and discussionThe results showed that the highest grain yield in irrigated planting medium was related to SUP152 genotype (3245 kg ha-1) which was not statistically significant different from WHEAR genotype which was in the second category. The MILAN/SHA7 genotype was also in the third place. These three genotypes also had high values in terms of yield components. The highest grain protein in irrigated planting medium belonged to REEDLING # 1 genotype with 11.73% which was not statistically significant difference with FRNCL and SAAR genotypes which were in the second and third ranks. The lowest grain protein in aqueous medium belonged to WHEAR genotype. The highest grain protein was obtained in the dryland medium of GASPARD genotype (13.73%). ND643 genotype was also in the second category but there was no significant difference with the first category genotype. Gonbad genotype was also in the third category and was one of the top genotypes. The highest grain yield was obtained in the dryland planting medium related to PBW343 genotype at the amount of 2051 kg ha-1. The lowest grain yield in dryland environment was related to PAURAQ genotype at 1457 kg ha-1. PBW343 genotype was one of the best genotypes in terms of yield components in rainfed planting environment. Distribution of hybrids based on YS, YP and MP and GMP indices showed that WHEAR, MILAN, CHIBIA// PRLII, PBW343 and SOKOLL3 genotypes are in group A and are water resistant and have high grain yield in both environments. And were selected as superior genotypes for both rainfed and irrigated environments.
Biotechnology and environmental stresses
Meisam Radfar; Seyyede Sanaz Ramezanpour; Hassan Soltanloo; Leila Kianmehr
Abstract
IntroductionWheat (Triticum aestivum L.) is one of the most important grains used in the world and its production is reduced in different regions due to drought stress. the plant antioxidant system can scavenge the reactive oxygen species (ROS) produced under drought. Induction of mutation using gamma ...
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IntroductionWheat (Triticum aestivum L.) is one of the most important grains used in the world and its production is reduced in different regions due to drought stress. the plant antioxidant system can scavenge the reactive oxygen species (ROS) produced under drought. Induction of mutation using gamma ray is one of the common methods for genetic modification and identification of tolerant and resistant mutants. Mutant T65-58-8 is one of these drought tolerant genotypes that has been obtained by irradiation to Tabasi wheat genotype. The wheat plant needs irrigation during the flowering stage and drought stress is very important in this stage. In this study, in the flowering stage, the enzymes superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR) and glutathione peroxidase (GPX) involved in the mechanisms of tolerance to oxidative damage of ROS in the flag leaf were studied and the expression of the genes related to these enzymes was investigated using RNAseq. method.Materials and methodsDrought stress was applied based on field capacity (FC). The experiment was performed as a factorial experiment in a completely randomized design with three replications. Factors studied in this experiment include genotype at two levels (Tabasi parent and Mutant T65-58-8) and drought stress at 5 levels (100% FC or control, 75%, 22%, re-sampling from control pots at 18% FC and sampling after re-irrigation to the pot when had 90% FC). Wheat growth stages can be studied by Zadoks index. SOD activity was measured by Minami and Yoshikawa method, CAT activity by Aebi method, GR activity by Foyer and Halliwell method and GPX activity by Hopkins and Tudhope method. RNA sequencing was performed using Illumina NovaSeq 6000. Gene expression was obtained based on sequencing data by Bowtie2, Tophat2, HTseq-count and Featurecount softwares. After normalization by generating FPKM, Log2FC gene expression was calculated.Results and discussionExamination of superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR) and glutathione peroxidase (GPX) indices showed a significant difference (p<0.01). Comparisons showed that SOD and CAT activity was higher in the mutant genotype at all stress levels. In the Tabasi genotype, re-irrigation increased the activity of SOD and CAT enzymes compared to the activity of this enzyme in field capacity 18%. In the study of GR and GPX enzymes, it was found that in both genotypes, the activity of this enzymes ancreases with increasing drought stress. In the Tabasi genotype, irrigation reduced the activity of GR enzyme and in the Tabasi and mutant genotypes, re-irrigation did not reduce the activity of GPX enzyme. Examination of GPX activity showed that this enzyme has a constant activity in mutant genotype under drought stress conditions. Examination of 21 genes related to SOD enzymes showed that six genes named FSD3(1), CSD1(2), FSD2(2) and CCS(1) mutant genotype had significant expression changes in drought stress conditions compared to the control. 6 catalase-related CAT1(3) and CAT2(3) genes from 14 genes related to CAT also had a significant increase in mutant genotype under drought stress compared to the control. One CAT1 gene and two CAT2 genes in mutant genotype had more expression in drought conditions than Tabasi genotype. 7 genes called CSA associated with GPX from 16 genes related to GPX also had a significant increase in mutant genotype under drought stress compared to the control. H2O2, KCN, chloroform-ethanol, sodium azide (NaN3), metal ions, carbohydrates, polyethylene glycol affect the activity of SOD. NaN3, amines, potassium cyanide and salicylic acid affect the activity of CAT. Gold, vitamin-E and selenium can also affect GPX activity.ConclusionThe study shows that the activity of SOD, CAT and GPX enzymes in both genotypes has increased under drought stress conditions. However, comparison of the expression of known genes related to these three enzymes shows that only some of these known genes have been altered. One FSD3 gene, two CSD1 genes, two FSD2 genes and one CCS gene had significant expression changes in the mutant genotype under drought stress compared to the control. This could be considered as confirmation of the increase in superoxide dismutase activity in the mutant genotype under drought stress, but the difference in expression of these 6 genes in the mutant genotype under drought stress compared to the Tabasi genotype under drought stress was not significant. This indicates that other factors in the mutant genotype under drought stress have increased the activity of SOD enzyme or limited the production or activity of this enzyme in the Tabasi genotype under drought stress. from the 6 altered genes expressed in the mutant genotype under drought stress compared to the control, one gene called CAT1 and two genes called CAT2 in the mutant genotype under drought stress showed more expression than the Tabasi genotype under drought stress. These genes can be introduced as genes involved in more tolerance of mutant genotype to drought stress than Tabasi genotype under drought stress. 7 genes called CSA had a significant change in expression in the mutant genotype under drought stress compared to the control, but these genes were not significantly different in the mutant genotype compared to the Tabasi under drought stress. Comparison of glutathione reductase enzyme in mutant and Tabasi genotypes in drought condition showed that the activity of this enzyme in the two genotypes was not significantly different. The activity of SOD, CAT and GPX enzymes can be inhibited or intensified by chemical agents and compounds.
Drought stress
Zohreh Hajibarat; Abbas Saidi; Habibolah Ghazvini
Abstract
IntroductionDrought is one of the most important factors limiting the environment for plant growth and productivity, especially in the flowering and filling stages of barley. A study was conducted to compare some statistical methods and different indicators of stress tolerance with the aim of introducing ...
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IntroductionDrought is one of the most important factors limiting the environment for plant growth and productivity, especially in the flowering and filling stages of barley. A study was conducted to compare some statistical methods and different indicators of stress tolerance with the aim of introducing an ideal method for selecting drought tolerant lines. After wheat, barley is one of the most important crops. Barley is the fourth cereal crop in the world after wheat, corn and rice. One of the factors affecting the production of plants is water defecit, and barley has more efficient mechanisms against water shortage than other grains. Because it has higher relative drought tolerance compared to other grains. In these arid and semi-arid regions like Iran, the presence of drought stress during plant growth is a natural problem.Materials and methodsIn this study, 18 diverse barley lines at two water levels (normal conditions and water deficit stress) were examined. This experiment was performed as a randomized complete block design with three replications at the Seed and Plant Improvement Research Institute of Karaj, Iran in 2020. Drought tolerance and susceptibility indices were assessed. These indices included stress sensitivity index, mean productivity, tolerance, stress tolerance index, geometric mean productivity, harmonic mean productivity, performance under stress conditions (Ys) and normal (Yp) conditions. Correlation coefficient between yield in drought and irrigation conditions and other stress indicators was estimated according to statistical techniques. Correlation between indices and grain yield under stress and normal conditions was calculated using Minitab software. Selection based on multiple traits in breeding programs is likely to be effective in improving grain yield under drought stress conditions. The purpose of this study is to identify the most suitable indicators and compare different stress tolerance indicators to select high-yielding and drought-tolerant lines and to identify the superior barley line.Results and discussionThe highest GMP and MP were related to 4 and 13 lines. Based on tolerance index (TOL), genotype 1 had the lowest and line 7 showed the highest level of tolerance, respectively. Based on MP and GMP indices, 4, 7 and 13 lines had high drought tolerance. A high positive and significant correlation was observed between MP, GMP, Ys, Yp, which indicates that these indices are suitable for identifying drought tolerant lines. Based on the results of the principal component analysis and the bi-plot diagram, it was observed that the lines tolerant to drought stress are almost consistent with the clustering pattern of tolerant lines and the lines sensitive to drought stress are also consistent with the clustering of sensitive lines. MP and GMP indices are suitable for evaluating drought tolerance because they showed a high correlation with grain yield under normal conditions and under water stress. The closeness of 4 and 13 lines to GMP, MP, HARM, Ys indicates the tolerance of these lines to drought stress and therefore they can be suggested as drought tolerant lines.ConclusionSelection of drought tolerant lines based on a combination of tolerance indices can provide useful criteria for drought tolerance. A high positive and significant correlation was observed between MP, GMP, Ys, Yp, which indicates that these indices are suitable for identifying drought tolerant lines. These results help the modifier to select lines in different environments. Principal component analysis showed that it is important to introduce genotypes with desirable traits such as genotypes with high yield and resistance to drought stress. It is possible to speed up the improvement of new barley cultivars by using stress tolerance indicators by breeders. In general, 4, 7, and 13 lines were drought tolerant and can be used for barley improvement programs. Based on principal component analysis, drought sensitive and tolerant lines were consistent with cluster analysis. Exploiting the results of the present study can help breeders to select and identify genotypes that have relative tolerance to drought stress.
Physiology of crops under stress conditions
Seyed Masoud Ziaei; Khaled Salimi; Seyed Reza Amiri; Mohammad Reza Rigi
Abstract
IntroductionSafflower has been cultivated in different parts of Sistan and Baluchestan since ancient times and is relatively tolerant of drought. It has many medicinal and food uses for the people of this region. Saravan is also one of the arid regions of the country, so the cultivation of plants compatible ...
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IntroductionSafflower has been cultivated in different parts of Sistan and Baluchestan since ancient times and is relatively tolerant of drought. It has many medicinal and food uses for the people of this region. Saravan is also one of the arid regions of the country, so the cultivation of plants compatible with these regions can be effective to improve agriculture in this region. Several studies have been shown that a small amount of nutrients, particularly Zn and Mn applied by foliar spraying can significantly increase the yield of crops Also, foliar nutrition is an option when nutrient deficiencies cannot be corrected by applications of nutrients to the soil. It is likely therefore, in open-field conditions, where the factors that influence the uptake of the nutrients are very variable, foliar fertilization is a privilege. Among the micronutrients, Zn and Mn nutrition can affect the susceptibility of plants to drought stress. Zinc plays an important role in the production of biomass. Furthermore, zinc may be required for chlorophyll production, pollen function, fertilization and germination. Mn plays essential roles in the metabolism of isoprenoids, chlorophylls, carotenoids and phenolics. External application of Mn2+ increases photosynthesis, net assimilation, and relative growth and yield.Materials and methodsthis experiment was conducted to investigate different levels of irrigation and foliar application of zinc and manganese sulfate in November 2020 in the research farm of Saravan Higher Educational Complex as a split plot in a randomized complete block design with three replications. Experimental treatments include three levels of irrigation, including: full irrigation, cessation of irrigation at the beginning of stem emergence and cessation of irrigation at the stage of flowering, and three levels of foliar application with zinc sulfate (three per thousand), manganese sulfate (three per thousand) and no foliar application. Study traits include speed, plant height, number of branches, number of heads per plant, seed weight per plant, head weight per plant, 100-seed weight, biological yield, grain yield and harvest index (division of grain yield by biological yield by percent). Data analyzed was performed using SAS software (version 9/1) and mean comparisons at the level of 5% probability were performed using LSD test.Results and discussionThe results showed that the interaction effects of irrigation and foliar application in plant height, number of branches, number of heads, 1000-seed weight, seed-per-plant weight, head-per-plant weight, biological yield, grain yield, harvest index and chlorophyll meter (SPAD) were significant (P≤ 1%). foliar application with zinc sulfate increased grain yield more than three times in all irrigation treatments, also grain yield in foliar application with zinc sulfate in non-interruption irrigation treatment (693 kg) Per hectare was seven times higher than the conditions for stopping irrigation at the stage of stemming and lack of foliar application (100 kg ha-1). In all irrigation treatments, foliar application of zinc sulfate Element was relatively superior to manganese sulfate and no foliar application. The highest grain yield was observed in the treatments of non-interruption of irrigation, cessation of irrigation in flowering stage and cessation of irrigation in stem stage, respectively. Was seven times the grain yield. In general, foliar application of zinc sulfate can be used as an agricultural solution to increase yield and reduce the effects of cessation of irrigation at the end of the growing season in safflower in Saravan climate. In general, the results of this study showed that under different conditions of irrigation interruption, foliar application of zinc sulfate and manganese can play an important role in mitigating the effects of drought stress on safflower compared to no foliar application. Discontinuation of irrigation at the end of the growing season in the stem and flowering stages reduced the seed yield of safflower compared to full irrigation conditions. Zinc sulfate foliar application improved yield-related traits in this plant, zinc sulfate foliar application increased grain yield about twice and in manganese sulfate foliar application this increase was about 30% compared to non-foliar conditions. The highest correlation was observed with number of heads per plant, head weight, seed weight per plant and number of branches. Due to the alkalinity of the soil in dry areas and the non-absorption of these elements by the plant and the positive effects of this element in relation to the defense system and photosynthesis of the plant, foliar application of zinc sulfate Element is recommended for safflower in Saravan climate.
Hadi Masjedi; Pourang Kasraei; Hamid Reza Rajab Larijani; Meysam Oveisi; Mohammad Nasri
Abstract
IntroductionThis experiment was performed to investigate the effect of microbial inoculation and urea fertilizer on Echinacea purpurea under water stress in two cropping years 2017-2018 and 2018-2019 in Ijan village located in Khondab city of Markazi province.Materials and methodsThe experiment was performed ...
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IntroductionThis experiment was performed to investigate the effect of microbial inoculation and urea fertilizer on Echinacea purpurea under water stress in two cropping years 2017-2018 and 2018-2019 in Ijan village located in Khondab city of Markazi province.Materials and methodsThe experiment was performed in the form of 2 split plots with 3 replications. The first factor included the lack of irrigation in the main plot at 3 levels of 60, 90 and 120 mm evaporation from the Class A evaporation pan. The second factor included animal manure (cattle) in the sub-plot at two levels, no fertilizer and 20 tons per hectare. The third factor of biofertilizer and urea fertilizer in the sub-plot in four levels of application of biofertilizer was Azotobacter+Azospirillum, Mycorrhiza, Aztobacter+Azospirillum+Mycorrhiza and application of urea fertilizer (300 kg ha-1). Flower number and weight, total dry matter yield, chlorophyll, relative water content, proline, catalase, carotenoid, chicoric acid and electrical conductivity of cytoplasmic membrane were measured.Results and discussionThe results showed that the interaction effect of manure and biofertilizer on flower weight was significant. The highest flower weight was obtained in the treatment of combined use of Azotobacter+Azospirillium+ Mycorrhiza and application of animal manure (295.9 and 236.3 g m-2, respectively), which was significantly different from urea consumption. The lowest flower weight was obtained in the treatment of separate mycorrhizal application and non-application of animal manure (0.216 236.3 g.m-2). The difference between the highest flower weight in the mentioned treatment with the lowest value was 36%. In the treatment of non-use of manure, the highest flower weight was obtained in the treatment of Azotobacter+Azospirillium+Mycorrhiza (236.3 g m-2). The interaction effect of manure and biofertilizer on chicory acid was significant. The highest chicoric acid was obtained in the treatment of combined use of Azotobacter+Azospirillium+Mycorrhiza and application of animal manure (7.53 mg g-1 fresh leaf weight). The lowest chicoric acid was obtained in the treatment of separate application of mycorrhiza and no application of animal manure (5.76 mg g-1 fresh leaf weight). The difference between the highest chicoric acid in the mentioned treatment with the lowest amount was equal to 30%. In the treatment of non-application of animal manure, the highest chicoric acid was obtained in the treatment of Azotobacter+Azospirillium+Mycorrhiza (7.17 mg g-1 fresh leaf weight).ConclusionIn general, microbial inoculation was able to achieve close quantitative and quantitative performance and sometimes more than urea fertilizer treatment, which can be a guide for identifying soil strains and producing biofertilizers compatible for areas with similar climates or soils.AcknowledgmentsThanks to all lecturers and staff of farm and laboratory department of agriculture department of Islamic Azad University, Varamin branch.
Heat stress
Behnoosh Sheikh Mamo; Afrasyab Rahnama; Peyman Hassibi
Abstract
IntroductionClimate change and global warming which are the consequences of rising temperatures, can affect agriculture in various ways. Heat stress is a serious threat to crop production in the world. Higher mean temperatures generally result in increased heat stress. This abiotic stress can adversely ...
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IntroductionClimate change and global warming which are the consequences of rising temperatures, can affect agriculture in various ways. Heat stress is a serious threat to crop production in the world. Higher mean temperatures generally result in increased heat stress. This abiotic stress can adversely affect crop productivity and quality and weaken global food security. With current increased average temperatures, the occurrence of heat stress could become more intense. Terminal heat stress is the most widespread heat stress, limiting crop yields. Terminal heat stress during the reproductive stages will have a negative influence on grain yield and oil quality traits of oil seed crops. Sunflower is an annual oilseed crop with adaptation to dry land or irrigated cropping systems. It is suited to both spring and summer planting in most regions and it will be exposed to major climate change and potentially impacted by high mean temperatures. Therefore, climate change and heat stress is a major production constraint for sunflower worldwide and it may be severely damaged when exposed to stresses above its tolerance threshold.Materials and methodsIn order to study of agronomic and physiological traits of sunflower cultivars under terminal heat stress, a field experiment was carried out during 2017-2018 growing season in Ahvaz conditions in a split plot arrangement in randomized complete blocks design with three replications. Main plots consisted of three sowing date including; 11th Nov, 11th Dec and 11th Jan, and sub plots consisted of five sunflower cultivars including; Qasem, Fantasia, Shams, Lakomka and Progress. Sowing date with desired temperature was considered as control, delayed and late sowing dates were considered as heat stress so that the flowering and grain filling periods of cultivars exposed to normal condition, moderate and severe terminal heat stress, respectively. Sunflower cultivars were evaluated under the optimum temperature (sown in the 11 November) and terminal heat stress condition (sown in 11 December and 11 January to expose the sunflower to higher temperatures than the optimum at the grain filling stage).Results and discussionTerminal heat stress in delayed and late sowing date caused a decrease in biological yield, grain yield, number of seeds per head, 1000-seed weight, head weight, oil yield, chlorophyll index, relative water content, chlorophyll content and stomatal conductance. There was a significant difference between cultivars in terms of all traits. Lakomka and Progress had the highest values of grain and oil yield under control conditions, respectively. Late sowing date was led to a significant reduction in grain yield of Qasem, Fantasia, Progress, Lakomka and Shams cultivars by 69, 38, 6, 31 and 14%, respectively, compared to control. It was equal to 2.2, 1.2, 0.2, 1.1 and 0.4% for each day of sowing delay, respectively.ConclusionLakomka cultivar showed higher oil yield in all three sowing date compared to other cultivars. In delayed sowing date, Progress cultivar showed higher oil yield due to higher grain yield and oil percentage. Due to the reduction of grain and oil yield in delayed sowing date, the perspective of sunflower cultivation in Khuzestan is probably related to its potential adaptation to climate change.
Drought stress
Hadi Tayfa Afshari; Bahram Mirshekari; Abollah Hasanzadeh Ghorttapeh; Farhad Farahvash; Mehrdad Yarnia
Abstract
IntroductionThe castor bean (Ricinus communis L.), is an oilseed of relevant economic and social importance. From its seeds is extracted an oil of excellent properties, having wide use as industrial input and several applications. It is cultivated since the times of the ancient civilizations, the castor ...
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IntroductionThe castor bean (Ricinus communis L.), is an oilseed of relevant economic and social importance. From its seeds is extracted an oil of excellent properties, having wide use as industrial input and several applications. It is cultivated since the times of the ancient civilizations, the castor bean is a rustic plant, resistant to drought, belonging to the family of Euphorbiaceae, Drought stress, in addition to the negative effect on yield, causes or exacerbates other stresses, especially the stress of nutrient deficiencies for the plant. The purpose of this investigation was study effect of irrigation levels and Superabsorbents and biofertilizers on the agronomic properties of castor oil.Materials and methodsThis experiment was conducted in West Azarbaijan Agricultural Research and Education Center, Orumieh- Iran at 2018-2021 crop season. Field experiment was carried out by a split plot design based on completely randomized block design with three replications. The first factor included Four levels (70, 100, 130 and 160 mm of evaporation pan),in the main plot and Sub-factor includes application of biofertilizer combination in four levels (Azospirillium, Citrobacter, combination of application of Azospirillium in Citrobacter and control without fertilizer) and superabsorbent in two levels (superabsorbent consumption and non-superabsorbent consumption) as factorial were placed in sub-plots. In this study, plant height, main length cluster, capsules number per plant, seeds number per plant, thousand kernel weight, biological yield, grain yield harvest index, oil percent and oil yield were measured. Also Traits were analyzed by using SAS 9.2 software and means comparison was tested by least significant difference (LSD).Results and discussionThe results of analysis of variance showed the effect of irrigation, biofertilizer and superabsorbent treatments at the level of 1% probability on plant height, number of seeds per plant, main cluster length, number of capsules per plant, 1000-seed weight, biological yield, grain yield, harvest index Oil percentage, oil yield, castor oil were significant. Also, the interaction effect of biosorbent and superabsorbent on plant height, number of seeds per plant, main cluster length and oil yield at the level of 5% probability and on grain yield, harvest index at the level of 1% probability was significant. The results showed that irrigation treatment after 160 mm of evaporation pan reduced plant height, number of seeds per plant, length of main cluster, number of capsules per plant, 1000-kernal weight, biological yield, grain yield, harvest index, oil percentage and oil yield in comparison with irrigation treatment after 70 mm by 7.62, 5.26, 12.19, 5.25, 5.86, 3.38, 9.50, 6.10, 2.38 and 11.83 percent, respectively. Among the biofertilizer treatments, seed inoculation with Citrobacter was able to increase the number of capsules, 1000-seed weight, biological yield and oil percentage compared to the control treatment by 5.5, 17.28, 2.74 and 8.50%, respectively. Among the interaction treatments, the highest plant height (165.21 cm), main cluster length (23.55 cm), grain yield (1137.61 kg ha-1), harvest index (20.72%) and oil yield (597.91 kg ha-1) was allocated to superabsorbent treatment and inoculation with Citrobacter.ConclusionIn this study, by exacerbation of water stress, all agronomic traits were reduced. It can be concluded that water deficit stress reduces the amount of photo assimilate and transfer of these substances by disrupting the photosynthesis process, and thus grain yield and yield components as well as oil percentage and oil yield are affected, Therefore, in order to achieve maximum economic yield in castor, irrigation should be done with a regular plan and the plant should not face long periods of drought as much as possible. In this study, the use of biological fertilizers, especially citrobacter, both individually and in combination with supergene had a positive effect on increasing grain yield and grain yield components, oil content and oil yield. Therefore, the use of these materials to improve the economic performance of castor oil is recommended.
