Ali Mahrokh; Majid Nabipour; Habib Alah Roshanfekr; Rajab Choukan
Abstract
Introduction Drought is one of the major environmental conditions that adversely affect plant growth and crop yield. In the face of a global scarcity of water resources, water stress has already become a primary factor in limiting maize production worldwide. It’s because Phytohormones such as auxin ...
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Introduction Drought is one of the major environmental conditions that adversely affect plant growth and crop yield. In the face of a global scarcity of water resources, water stress has already become a primary factor in limiting maize production worldwide. It’s because Phytohormones such as auxin and cytokinin are reported to be involved in the regulation of plant response to the adverse effect of drought stress conditions. This study carried out in order to evaluate some physiological parameters response to auxin and cytokinin hormone alternation under drought stress condition on maize (cultivar KSC 704). Materials and Methods The experiment was carried out in three separately environments included non-drought stress environment (irrigation after soil moisture reached to 75% field capacity), drought stress in vegetative stage (irrigation after soil moisture reached to 50% field capacity in V4 to tasseling stage, but irrigation after soil moisture reached to 75% field capacity in pollination to physiological maturity stage) and drought stress in reproductive stage (irrigation after soil moisture reached to 75% field capacity in V4 to tasseling stage and irrigation after soil moisture reached to 50% field capacity in pollination to physiological maturity stage). cytokinin hormone in three levels (control, spraying in V5 –V6 and V8-V10 stages) and auxin hormone in three levels (control, spraying in silk emergence stage and 15 days after that) was laid out as a factorial design based on randomized complete block with three replications in each environment at Seed and Plant Improvement Institute (SPII), Karaj, Iran, in 2013. It was used Indole-3-butyric acid and N6-benzyladenin as auxin and cytokinin hormones respectively. Concentration of used auxin and cytokinin hormones were 10 and 50 mg per liter respectively. In this study some physiological parameters were measured including leaf area index, cell membrane stability, leaf chlorophyll content, stomata conductive, canopy temperature depression, photosynthesis quantum efficiency and leaf senesce. Results and Discussion The maximum leaf area index, stomata conductance and quantum efficiency of photosynthesis and the minimum canopy temperature were obtained with spraying cytokinin hormone in V8-V10 stage, and the maximum chlorophyll content index, quantum efficiency of photosynthesis and the delay in leaf senescence were obtained with spraying auxin hormone in silk emergence stage and the minimum stomata resistance and canopy temperature were obtained with spraying cytokinin hormone in 15 days after silk emergence stage. The interaction effect between drought stress and spraying hormone was significant on leaf area index and canopy temperature depression and spraying hormones on maize in drought stress condition in reproductive stage more effective than non-drought stress and vegetative drought stress conditions because it can be useful in balancing the disturb hormone relations.Conclusion Based on the result of this experiment, maize is tolerant to drought stress in vegetative stage, as a result, irrigation after soil moisture reached to 50% field capacity in vegetative stage and irrigation after soil moisture reached to 75% field capacity after tasseling stage can save irrigation water without any decrease significantly in physiological parameters at erase where water has been limited. Spraying cytokinin and auxin hormones in V8 –V10 and silk emergence stage can be recommended as the best time to use these hormones respectively. Using auxin and cytokinin hormones under drought stress condition in maize was more effective than control and vegetative stage because they can balance the disturbed hormones rate under that condition.
Seyed Mohammad Javad Bahrololomi; Mahmoud Raeini Sarjaz; Hemmatollah Pirdashti
Abstract
Introduction Environmental stresses, in addition to their straight effects on plants growth and development, induce oxidative stresses on plants. These secondary stresses cause degradations on cell wall lipids and cell organelles proteins. In response to overflow of reactive oxygen species (ROS) enzymatic ...
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Introduction Environmental stresses, in addition to their straight effects on plants growth and development, induce oxidative stresses on plants. These secondary stresses cause degradations on cell wall lipids and cell organelles proteins. In response to overflow of reactive oxygen species (ROS) enzymatic and non-enzymatic antioxidants productionscould be induced in plants. Due to the kind and intensity of environmental stressesand plant physiological pathways the activity responses of antioxidant enzymes could be different. Therefore, the aim of this research was to evaluate the effect of water stress on soybean antioxidants induction. Materials and Methods This trial was done on spring and summer 2012 in Sari Agricultural Sciences and Natural Resources University (SANRU) research station, Sari, Iran. The JK variety of soybean (Glycine max L.), which is widely cultivated in the region was selected for this purpose. A completely randomized design with 4 soil available water (AW) treatments in a pot experiment was employed. After 4-leaf stage soybean seedlings were randomly assigned to 4 water treatments of control, with 100 percent (well-watered, W0), 60 percent (mild stressed, W1), 40 percent (intermediate stressed, W2) and 20 percent (severe water stressed, W3) of soil AW. Plants were re-watered to 100 percent AW upon reaching to the assigned water level. During the R4 and R5 reproductive stages leaf samples were collected to measure leaf catalase and peroxidase enzymes and MDA and leaf total nitrogen and seed weight per plant using spectrophotometer and autoanalyzer. Data were analyzed using SAS software and mean comparisons were done using Tukey post-hoc test. Results and discussion Findings of this research showed that water stress significantly (p ≤ 0.05) affected leaf enzymatic activities of catalase and peroxidase, and influenced malondialdehyde (MDA) and total nitrogen contents and seed weight per plant. The catalase enzyme activity increased up to 60% AW, Then declined by further increase in soil available water. A highly significant quadratic relation (R2 = 0.89; P ≤ 0.01) was found between this enzyme activity and soil available water. The trend of variations in peroxidase activity by reduction in soil AW was highly positive and significant (P ≤ 0.01). The amount of this enzyme in water stressed treatments relative to control increased by 18.7, 29.9 and 34.4 percent, respectively. A highly significant, but negative correlation (r = - 0.86; P≥0.01) was found between MDA values and soil available water. The variation trend of leaf soluble proteins relative to soil available water was decreasing and significant differences were found between control and stressed treatments of W2 and W. The leaf total nitrogen contents increased by reduction in soil available water (r = 0.84; P ≤ 0.01). Also, seed weight per plant as an index of plant performance up to 60% of available water was ascending and in the moisture content of 80% available water, due to the increasing trend of all antioxidants to the highest. Conclusion It could be concluded from these findings that increase of antioxidant enzymes, due to mild water stress, could diminish destructive effects of reactive oxygen species (ROS) in soybean. Antioxidant activities to a certain level of water stress, in this case up to 60% of AW, had an effective protective effect on photosynthesis process, therefore on soybean seed yield. It seems catalase activity was more effective on severe water stresses compared with peroxidase enzyme.
Hamdollah Eskandari; Ashraf Alizadeh-Amraie; Kamyar Kazemi
Abstract
Introduction Intercropping, defined as planting two or more crops simoultanously in a same field during a specific growing season, is an agronomical operation which has important advantages such as improving water use efficiency, increasing land use efficiency and yield compared with sole crop systems. ...
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Introduction Intercropping, defined as planting two or more crops simoultanously in a same field during a specific growing season, is an agronomical operation which has important advantages such as improving water use efficiency, increasing land use efficiency and yield compared with sole crop systems. Because of lowering available water for agronomical operations, water conservation methods are in high importance in agronomical systems. Partial root zone irrigation has been considered during recent years. In this method, half of root system is irrigated and other half is subjected to dry soil. In wheat maize intercropping it has been reported that partial root zone irrigation improved water use efficiency (Yanh et al., 2011). The purpose of this experiment was evaluating the effect of water deficit induced by partial root zone irrigation in growth and grain yield of maize and mung bean in intercropping and sole cropping systems to assess the possibility of improving water use efficiency. Materials and Methods The experiment was conducted as a field experiment during 2016-17 growing season in Lorestan province. A tw-factors factorial experiment based on randomized complete block design with three replications was employed to compare the treatments. The fist factor was irrigation (including conventional irrigation (I1) and partial root zone irrigation (I2)) which was applied after seedling establishment. The second factor was planting pattern including sole maize, sole mung bean, within-row intercropping and between-row intercropping. Water consumption and leaf area index were measured during growing period. At harvest time, grain yield and yield components were determined. Water use efficiency was measured by dividing grain yield on water consumption. Land equivalent ratio was used to evaluate the advantage of intercropping. Results and Discussion The highest grain yield of maize was recorded in sole cropping system under conventional irrigation. The lowest grain yield of maize was achieved in between-row intercropping under partial root zone irrigation. There was a reduction in grain yield with lowering water availability. Leaf area index of maize in partial root zone irrigation system was lower than that of conventional irrigation. Partial irrigation reduced all yield component of maize including grain number and weight. However, the effect of water deficit on grain weight was more than grain number. Lower plant number per unit area can be considered as a cuase of the lower grain yield of maize in between-row intercropping. Furtheremore, reducing leaf area index under partial root zone irrigation showed a reduction in leaf size and number, resulting in lower solar radiation absorption and, finally, reduction of photo assimilates synthesis. The highest yiel of mung bean was achieved under conventional irrigation and sole cropping system which was not significanlt difference with within-row intercropping. Mung bean produced the lowest grain yield in between-row intercropping in partial root zone irrigation. Generally, partial root zone irrigation reduced mung bean grain yield in all treatments with the amount of 29%, 22% and 21% for soel cropping, between-row intercropping and within-row intercropping, respectively. Although the highest grain yield was achived from maize sole cropping under conventional irrigation, the highest waer use efficiency of this treatment was lower than that of sole maize and within-row maize-mung bean intercropping. In all treatment, water use efficiency was improved by applying the partial root zone irrigation system which its highest value was recorded for maize-mung eban intercropping (43%) and mung bean sole cropping (39%). Land equivalent ratio of both interropping systems under partial and conventional irrigation was more than one, indicating the advantage of intercropping. The advantage of within-row intercropping under both irrigation systems was two times more than that of sole cropping. Conclusion Yield and yield components of maize and mung bean were reduced under partial root zone irrigation due to the reduction of grain weight and number. Reduction of water consumption through partial root zone irrigation improved water use efficiency. The results of this experiment revealed that maize mung bean intercropping under partial root zone irrigation can produce optimum grain yield while improving water use efficiency.
Mohsen Rezaei; Hoosein Sabouri; Abdollatif Gholizadeh; Rahmatollah Mohammadi Gonbad
Abstract
BackgroundBarley (Hordeum vulgare L.) is one of the most important cereals in the world. Drought is one of the most important abiotic stress and severely limits the production of barley around the world. Diversity is the basis of all screenings and genotypic selection also needs diversity. The use of ...
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BackgroundBarley (Hordeum vulgare L.) is one of the most important cereals in the world. Drought is one of the most important abiotic stress and severely limits the production of barley around the world. Diversity is the basis of all screenings and genotypic selection also needs diversity. The use of haplotypes in the study of genetic relationships is important. This is more important when there is little indication of the power of the individual's markers, or when there are several genetic markers in the selected QTLs. Association analysis and study of the relationship between molecular markers and agronomic traits have several applications, including the possibility of studying the genetic potential of specific genotypes before phenotyping, identifying alleles related to traits in the germplasm, facilitating locating QTLs and validation of candidate genes responsible for quantitative traits. The aim of this experiment was to investigate the allelic variation, association analysis and haplotypes of continuous microsatellite markers to drought tolerance genes in the barley. Materials and methodsThe experiments were carried out as an augmented design with 96 barley genotypes along with four controls. 18 traits were evaluated on the plants. Then, to evaluate the allelic and haplotypic diversity, the genotypes were tested using five microsatellite markers related to drought tolerance. In the end, phenotypic information was compared with genotypic information, and the relationship between them was determined by linear forward regression. FindingsThe analysis of the data obtained from the markers revealed that there were 26 multivariate alleles and also an average of 3.429 alleles for each marker, with the highest number of GBMS180, GMBS183 and EBmac0755 markers with 6 alleles. The results of the PIC show the highest value of the GBMS180 marker and the lowest value of the Bmag0782 marker; the mean of PIC was also 0.6267. The genetic diversity was also between 0.7117 and 0.7602 with an average of 0.6807. The GBMS180 has the highest value and the Bmag0782 has the lowest value. Haplotype evaluation of microsatellite markers on 96 genotypes studied genotypes in fifty-eight haplotype groups, among which the third haplotype group had the most sub cluster with three genotypes. The nineteen group, which included genotype 134, with the highest yield and drought tolerant, with 5183.333 kg ha-1. The results of the coupling analysis indicated that the GMBS183-D allele was involved in controlling four traits of the number of spikes, spike weight, number of seeds per spike and yield, and had the greatest effect among other alleles on the increase or decrease in yield and its components. DiscussionLinear regression and haplotype studies did not overlap, although the forward linear regression of alleles was studied individually and the allelic groups were able to interact with each other, but the obtained data did not have two match methods. But a comparison of the results of allelic variation was similar to linear regression and showed GMBS183, which had the highest PIC, among four attributes related to yield and its components in controlling the three traits of the number of spikes, number of seeds per spike and yield. This marker was also present in control of days to physiological reppining, which plays an important role in plant escape from the stresses, especially drought stress, and R2 is equivalent to 15.4%. This suggests that the results of linear regression match the results of the allele variation and overlap each other.
Mehdi Kakaei
Abstract
Introduction Drought stress and water availability restrictions have always been the most important issue in agriculture in the world and Iran, and this is the most important factor in reducing plant production and Determination and identification of effective factors on wheat seed yield under water ...
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Introduction Drought stress and water availability restrictions have always been the most important issue in agriculture in the world and Iran, and this is the most important factor in reducing plant production and Determination and identification of effective factors on wheat seed yield under water deficient condition is very important. Iran with were an average rainfall of 240 mm per year is among the arid and semi-arid areas of the world, with this precipitate, the main factor influencing the plant's performance is drought stress. In dry and semi-arid regions due to peripheral dryness and available moisture constraints, the yield of wheat plants decreases dramatically. According to meteorologists, dry weather can occur when rainfall is less than the average of long-term rainfall in a long period of time. However, from the agricultural point of view, if the distribution of rainfall is so low that it causes a significant reduction in the yield of plants, then land has occurred. Considering the importance of wheat as an important and strategic product in Iran, due to the droughts that are occurring (precipitation below the normal level), The purpose of this study was to study the response of some cultivars of genotypes in Asadabad city to the end of the drought stress, identification of higher yield genotype (s) and also determining the characteristics that affect the yield of the present research. Material and method In order to This study was designed to investigate the genetic diversity and relationships between yield and related other traits (Study of irrigation and correlation of some physiomorphological traits with wheat yield) in 17 wheat genotype and were investigated at completely randomized design with three replications in 2009-2010 under two conditions (drought stress and non-drought stress). An experiment was conducted at the experimental field of the payame Noor University of Asadabad and the agricultural group laboratory located at the provincial lab. Each plot consisted of 5 lines 2 meters long with a distance of 20 cm and a plot distance of 50 cm. Irrigation was carried out in conditions without drought stress according to the custom of the area, However, under irrigation conditions, irrigation was not done and weed combat was carried out manually and in one step (the first stage of stemming). The harvest took place in the middle of July 2011. In order to carry out notes on the study of traits, five genotypes were randomly selected in each replicate. 14 agro-morphological traits were including (Yield stress, Yield potential, Number of Seed Per Spike, Spike Length, Flag leaf Length, Width leaf Length, 100 Kernel Weight, Plant Height, Relative Water Content, Relative Water Loss, SPAD, Area flag leaf and Single Seed weight) measured. Result and discussion Analysis of variance revealed good differences among genotypes for two condition drought stress and non-drought stress. Among the traits, the highest coefficient of phenotypic variation was observed for seed yield with SPAD (drought stress condition) and seed yield with Relative Water Loss. Cluster analysis subdivided the genotypes into 3 groups. The maximum distance were observed between the genotype from groups 1 and 3. According to the comparison of mean grain yield, genotypes 7, 8 and 13 showed high yield under moisture conditions and genotype 13, 14 and 17 produced higher yields under drought stress conditions. In this study, the effects of stress have reduced the function of genotypes. However, the decreasing values in different genotypes are different, so that sensitive genotypes were with the highest yield loss and endemic genotypes with the least functional deficiency faced.
Bahamin Seyed Hayat Gheyb; Mani Mojaddam; Nazli Derogar
Abstract
Introduction Barley (Hordeum vulgare L.) is one of the oldest crops, and its cultivation dates back to 7,000 years BC. This plant is the least expected crop, whose range of adaptation and distribution is more than other crops. Barley is the fourth most important cereal in the world after wheat, rice ...
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Introduction Barley (Hordeum vulgare L.) is one of the oldest crops, and its cultivation dates back to 7,000 years BC. This plant is the least expected crop, whose range of adaptation and distribution is more than other crops. Barley is the fourth most important cereal in the world after wheat, rice and corn. The origin of the barley region is fertile. It has diploid and tetraploid species, but its cultivars are diploid. Water is a key factor in the production of crops. The yield of crops in many areas is limited by living or non-living environmental stresses, and therefore, there is a significant difference between actual yield and yield potential of crops. Low moisture content in each of the different stages of growth reduces water absorption, nutrients, decreases the transfer of elements within the plant, and ultimately reduces the yield of the grain or the final product. Optimal use of water is of great importance, especially in areas where dry climatic conditions and Semi-dry is dominant. Materials and methods In order to evaluate the effect of effect of zinc sulfate on quantitative and qualitative characteristics of barley in late season drought stress conditions, a field experiment was carried out to in Baghmalek province in 2016-17 in split plot based on randomized complete block design with four replications. Experimental treatments included three levels of Irrigation cut at flowering stage, Irrigation cut at grading stage and Full irrigation In main plots and Zinc sulfate fertilizerwas 34% in three levels (0 (control), 30 and 60 kg.ha-1) in sub plots. Results and discussion The results showed that drought stress in the end of the season had a significant effect on grain yield, number of seeds per spike, 1000 seed weight, protein content and protein yield. Also application of manganese Zinc sulfate fertilizer significantly affected yield components, grain yield and protein yield. The highest number of spikes per square meter was allocated to 60 kg / ha treatment with 381.61 and the lowest number of spikes per m2 for non-application of Zinc sulfate fertilizer treatment to 334.85. It seems that Zinc sulfate fertilizer in plants increases photosynthesis and photosynthesis, as well as increasing the amount of auxin hormone increases plant growth and spike production by the paws. Due to the lack of malnutrition, the number of spikes per square meter increases. The highest grain yield (389.6 g/m²) was obtained from 60 kg.ha-1 Zinc sulfate fertilizer and the lowest (2336.3 g/m2). The highest grain yield in irrigation treatments (with a mean of 381.3 g / m2) and the lowest grain yield (with a mean 252.52 g / m2) were allocated to irrigation cut off at flowering stage. Studies have shown that moisture restriction at flowering time reduces the transfer of photosynthetic materials and, consequently, wrinkles the grain. In contrast, moisture availability in the flowering stage increases the grain filling period, resulting in more photosynthetic materials for seeds, which increases seed yield. Interaction between end season drought stress and Sulphate fertilizer had a significant effect on grain yield. The highest grain yield was allocated to full irrigation treatment and 60 kg.ha-1 Zn sulfate fertilizer treatments. Conclusion In general, it can be stated that the soils of many southern regions of the country are limestone with high pH and low organic matter and zinc deficiency is very probable. In this research, it was determined that fertilizer use plays an important role in the growth of oat plants, and also considering that the highest grain and protein yields as a quantitative and qualitative function of using Zn sulfate fertilizer, which is one of the low-level elements. To be achieved. It can be concluded that by using such fertilizers, the best conditions can be obtained to achieve the maximum quantitative and qualitative yield of the barley plant. Therefore, in terms of implementation of this research, 60 kg / ha Zn sulfate fertilizer application and irrigation had the most significant effect on the studied traits.
Sara Daylami; Mani Mojaddam
Abstract
Background and Objectives The cowpea (vigna unguiculata L.) including grains, grown in tropical and sub-tropical countries, especially in the countries of Asia, Africa and South America, and it is considered an important source of nutrition. Among legums, in terms of cultivars and economic value, the ...
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Background and Objectives The cowpea (vigna unguiculata L.) including grains, grown in tropical and sub-tropical countries, especially in the countries of Asia, Africa and South America, and it is considered an important source of nutrition. Among legums, in terms of cultivars and economic value, the first place belongs to beans. Good climate (warm to moderate summer) and adequate water in the areas under beans, high quality soils and high depth of clay are the main reasons for increasing its cultivation area. Water is a key factor in the production of crops. The yield of crops in many areas is limited by living or non-living environmental stresses, and therefore, there is a significant difference between actual yield and yield potential of crops. Low moisture content in each of the different stages of growth reduces water absorption, nutrients, decreases the transfer of elements within the plant, and ultimately reduces the yield of the grain or the final product. Optimal use of water is of great importance, especially in areas where dry climatic conditions and Semi-dry is dominant. Therefore, the present study aimed to investigate the effects of humic acid spraying on the quantitative and qualitative characteristics of bean-eyed beans under irrigation regimes in Hamidieh region. Materials and methods This research was carried out in 2016 in a farm located in Hamidieh with a longitude of 48 degrees and 10 minutes east and 31 degrees and 33 degrees north latitude and 13 meters above sea level. This study was carried out as split split plot in a randomized complete block design with three replications. Treatments included irrigation regimes at three levels (60, 90 and 120) mm evaporation from class A evaporation pan in the main plots and different times of humic acid spraying at three levels (no spraying, spraying at vegetative stage, Spraying at flowering stage) in sub plots. Results The results showed that irrigation regimes had a significant effect on grain yield, number of pods per plant, number of seeds per pod and protein yield. The highest grain yield (205.42 g/m2) was obtained from 60 mm evaporation from the evaporation pan and the lowest with an average of 160.2 g/m2, with 120 mm evaporation from evaporation pan. Also, the application of humic acid spraying dates significantly affected seed yield and protein function. Humic acid increases the amount of nutrients (seed storage compositions) by increasing the activity of the rosicose enzymes and increasing the photosynthesis activity of the plant, possibly by improving the production of sugar, protein and vitamin in the plant, and the positive effect on the various aspects of photosynthesis.The highest grain yield (200.77 g/m2) was obtained from spray application during vegetative time and the lowest (152.52 g/m2) was obtained from non-spray application. The interaction of irrigation regimes and spraying periods of humic acid had a significant effect on grain yield. The highest grain yield was assigned to 60 mm evaporation from evaporation pan and humic acid spraying treatment at a vegetative stage of 213.88 g/m2. Conclusion Therefore, it can be concluded that the use of humic acid due to different physiological effects, in addition to increasing yield, can play a positive role in decreasing the use of chemical fertilizers as well as environmental pollution. Therefore, as a natural source material, To sustain and increase the production of crops. Drought stress increased protein percentage, but irrigation at flowering and podding stage reduced the protein percentage. Despite the high percentage of protein in 120 mm evaporation from the pan, the protein function in this treatment was less than the other two treatments due to low grain yield. Therefore, in order to achieve maximum grain yield, 60-millimeter water irrigation with evapotranspiration from the pan is recommended by application of humic acid spraying at the vegetative stage.
Ghader Rostami; Mohammad Moghaddam; Elham Saeedi Pooya; Ladan Ajdanian
Abstract
IntroductionSpearmint is one of the plants that attracted the attention of researchers because of its economic and pharmaceutical importance. This plant is one of the most important and most famous species of mint which disperses in different parts of the world. One of the scarce resources that is affected ...
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IntroductionSpearmint is one of the plants that attracted the attention of researchers because of its economic and pharmaceutical importance. This plant is one of the most important and most famous species of mint which disperses in different parts of the world. One of the scarce resources that is affected by rainfall is water. The effect of water stress depends on the duration, durability and amount of deficiency. One of the most important factors limiting the growth of plants around the world is drought, which is the most common environmental stress. One of the most effective mechanisms that is used by plant in water stress condition is osmotic regulation. The accumulation of proline and soluble sugars (as the most important osmolite) in regulation of osmotic is done to dominate the negative effects of drought stress. Results of researches have shown that drought stress has effective effect on the growth and biochemical characteristic of plants, and it differs among different plants. Optimum plant nutrition is one of the effective methods for plant resistance in drought conditions. Humic acid is one of the most important fertilizers in the agriculture. It creates more space for water penetration by modifying physical soil characteristic and improving soil granulations. Humic acid increases the activity of photosynthesis by increasing the activity of the Robisco enzyme. To consider the high importance of spearmint as a valuable vegetable and medicinal plant, the aim of this study was to estimate the resistance of spearmint to different levels of drought stress and evaluate the effects of foliar application humic acid as a moderator factor in drought stress condition. Materials and methodsA pot research was conducted in factorial experiment in a completely randomized design with 3 replications to investigate the effects of humic acid as a growth factor and moderator of the effect of drought stress, on Mentha spicata L. at the Faculty of Agriculture, Ferdowsi University of Mashhad. The first factor was three levels of drought stress (30, 70 and 100 % FC) and the second factor was four levels of humic acid (0, 100, 500 and 1000 mgL-1). At the firstly, spearmint rhizomes with 10 cm length were prepared with at least 2 buds. In the middle of March, about 4 rhizomes were cultivated in depth of 5 cm of pots soil. Foliar application of humic was used at three stages (one week before drought stress and one and three weeks after applying drought stress) on the plant surface. We didn’t use any humic acid on the control treatment. About 4 weeks after humic acid application, the morphological, physiological and biochemical traits were measured at flowering stage. ResultsVegetative traits such as plant height, number of branches, leaf length, leaf width and fresh and dry weight of leaf and stem showed a significant decrease with increasing drought stress (70% of field capacity) in compared to control treatment. Foliar application of humic acid, especially 1000 mgL-1 improved these traits in compared to control plants in drought stress condition. Also, the mean comparison of the interaction treatments showed that the highest amounts of photosynthetic pigments was observed at 70% FC and application of 1000 mgL-1 of humic acid and the least one was belonged to control treatment and application of 500 mgL-1 of humic acid. The highest antioxidant activity of leaf extract (80.66%) and total phenol (0.87 mg/g fresh weight) were observed in plants treated with 1000 mgL-1 humic acid and 70% FC. The highest relative water leaf content was obtained at non-stress conditions (control) and the foliar application of 1000 mgL-1 of humic acid. ConclusionThis study showed that spearmint is very susceptible to drought stress, which could not withstand drought stress of 30% FC even for a short time. In general, means comparison of results showed that drought stress significantly reduced the morphological traits of spearmint. Also, the interaction treatments showed that the using of 1000 mgL-1 humic acid had the greatest effect on the growth indices. The highest amounts of photosynthetic pigments was observed at 70% FC and foliar application of 1000 mgL-1 of humic acid and the lowest one was belonged to control treatment of humic acid and without stress condition. Also, the highest levels of total phenol and antioxidant activity were observed in 70% FC and 1000 mgL-1 humic acid treatment. Therefore it can be stated that spearmint is high susceptible plant to drought stress because of sever effects of drought stress on its growth characteristics and physiological processes. The foliar application of humic acid, especially at high concentration (1000 mgL-1) can be effective in regulating the osmotic potential under slightly drought stress conditions. So, it can be used as an organic fertilizer in sustainable agriculture.
Hamdollah Eskandari; Kamyar Kazemi
Abstract
IntroductionUndr the condition of simoultaniousley irrigation of some crops, there is a shortage of water for irrigation. In this conditions, scheduling of the irrigation is crucial. In irrigation programs, evaporation pan is widley used. There are some reports for the effet of deficit irrigation on ...
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IntroductionUndr the condition of simoultaniousley irrigation of some crops, there is a shortage of water for irrigation. In this conditions, scheduling of the irrigation is crucial. In irrigation programs, evaporation pan is widley used. There are some reports for the effet of deficit irrigation on grain yield of sesame, where drought stress reduced growth and grain yield of sesame from 1212 to 624 kg ha-1 (Mehrabi and Ehsanzadeh, 2012). Application of fertilizers with ecological source, including animal manure and compost, can be used instead of chemical fertilizers, where application of such fertilizers can supply nutrients for crops, increase soil fertility and also maintain organic matter of the soil. Since the effect of fertilizer on the grain yield of sesame under different irrigation conditions is not well documented, the current research was aimed to determine the response of sesame to the source of nutrient under drought stress conditions. Materials and MethodsA field experiment was conducted in Shadegan, Khuzestan province, during 2016-17 growing season to evaluate the effect of chemical and organic fertilizers on yield and yield components of seasame under different irrigation conditions. The experiment was conducted as a split plot based on RCBD with three replication where irrigation levels (irrigation after 100, 200 and 300 mm evaporation from evaporation pan) were assigned as main plot and fertilizer type (control, chemical fertilizer including 250 and 100 kg ha-1 phosphorous and nitrogen fertilizers, respectively, 30 t ha-1 animal manure and 30 t ha-1 compost) were allocated to sub plots. All compost, animal manure and ammonium phosphate and half of nitrogen fertilizer were applied before planting. At harvest time, plant height, leaf number per plant, branch per plant, capsule per plant, grain per capsule, 1000-grain weight and grain yield were measure. Harvest index and oil percentage were also determined. Results and discusionsThe highest plant highet was achieved in 100 mm evaporation from evaporation pan which was not significantly difference with the irrigation interval of 200 mm mm evaporation from evaporation pan. The lowest plant height was recorded in control treatment which was 25, 20 and 10 percent lower than that of chemical fertilizer, animal manure and composr, respectively. the most leaf number was recorded in 100 mm evaporation from evaporation pan. Application of chemical fertilizer produced the highest leaf number. Irrigation interval of 100 mm evaporation from evaporation pan had the highest branch per plant.Sesame had the highest capsule per plant and 1000-grain weight in 100 mm evaporation from evaporation pan which was not significantly difference with 200 mm evaporation from evaporation pan. Application of chemical and animal fertilizers produced highest capsule per plant. However, compost had no significant effect on this trait. Irrigation after 300 mm evaporation from evaporation pan resulted in te highest harvest index. The lowest oil percentage (47.5%) of sesame was achieved in 300 mm evaporation from evaporation pan and no application of fertilizer. The highest oil yield of sesame was recorded in 100 mm evaporation from evaporation pan which was 17% and 43% more than that of 200 and 300 mm evaporation from evaporation pan. Application of animal manure and compost resulted in 35.5% and 16% increase of oil yield.
Sadegh Bahamin; Alireza Koocheki; Mahdi Nassiri Mahallati; Seyed Alireza Beheshti
Abstract
Introduction The reduction of nutrients in agricultural soils is led to the intensive use of fertilizers because of low nutrients use efficiency of production systems (Taheri Oshtrinani and Fathi, 2016). An optimal level of nitrogen in the soil is requried to ensure vegetative growth, greater leaf area ...
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Introduction The reduction of nutrients in agricultural soils is led to the intensive use of fertilizers because of low nutrients use efficiency of production systems (Taheri Oshtrinani and Fathi, 2016). An optimal level of nitrogen in the soil is requried to ensure vegetative growth, greater leaf area and proper yield with the minimum environmental consequences (Zabet et al. 2014; Bahamin, 2011). In this research chemical and biological sources of nutrients are compared for yield formation in water-stressed maize. Materials and Methods This research was carried out to investigate the effect of nitrogen and phosphorous fertilizers on yield quantity and quality of corn under drought stress. For this purpose, a split plot experiment with 4 replications was conducted in a randomized complete block design in 2015 at the Agricultural Research Station of Mehran (33° 07' North and 46° 10' East), southwest of Ilam province. The main plot factor included 3 irrigation regims of: irrigation up to 100% field capacity (no stress control), irrigation up to 75% of field apacity (moderate drought stress) and irrigation up to 50% field capacity (severe drought stress) and factorail combination of 3 levels of nitrogen and phosphorous fertilizers (including unfertilized control) was assigned to subplots. Recommended level of nitrogen was applied in the form of chemical fertilizer (in three stages before planting, stemming and flowering), or Azotobacter (seed inoculation) and the recommended rate of phosphorus was applied either in chemical form (triple superphosphate) or biological (seed-inoculated Pseudomonas fluorescens). Results and Discussion The effect of drought stress, nitrogen fertilizer, phosphorus fertilizer and interaction of all treatments on grain yield was significant. The highest grain yield of 12372 kg/ha was obtained with full irrigation when nitrogen and phosphorous were applied in chemical form. However, the same level of corn yield was achieved with biological nitrogen+chemical phosphorpus or chemical nitrogen+biological phosphorous. At all levels of drought stress application of triple super phosphate+azotobacter resulted to a significanty higher yield compared to unfertilized control. Based on the results under the severe drought stress (50% of field capacity) grain yield of 8093.6 kg/ha was obtained with azotobacter and triple superphosphate. The effect of drought stress, nitrogen fertilizer, phosphorus fertilizer and interaction of all factors on protein yield of corn was significant. The highest protein yield of 1105 kg//ha was achieved in full irrigation when triple supplemented was combined with azotobacter. At all levels of water stress application of triple superphosphate together with azotobacter was led to a significnatly higher protein yield compared to control so that under severe drougth stress with triple superphosphate+azotobacter the protein yield was 639.4 kg/ha. However, under moderate water stress (75% of field capacity) protein yield was 774.4 kg/ha with Pseudomonas+Azotobacter wich was significanty higher that other combination of fertilizers under moderate stress. In severe stress treatment (50% of field capacity) chlorophyll a was 15.1 mg/g of leaf fresh weight, which was 13.7% higher than full irrigation treatment. The highest amount of chlorophyll b (4.92 mg/g of leaf fresh weight) was obtained when Azotobacter was applied together with super phosphate. Regardless to the source of phosphorus fertilizer the amount of chlorophyll b was highest with Azetobacter. Protein content was also maximum (9.32%) in Azotobacter+super phosphate combination. Conclusion Overall, the results of this study showed that Pseudomonas and Azotobacter in low and severe water stress conditions increased the quantitative and qualitative yield of corn. Furthermore, it can be concluded that biofertilizer Pseudomonas and Azotobacter can supply most of the nutrient requirements of maize particularly when water is limited.
mohammad ghasem jami; Amir Ghalavand; S. Ali Mohammad Modarres-Sanavy; Ali Makhtassi-Bidgoli; Abolfazl Baghbani Arani; Amin Namdari
Abstract
IntroductionThe sunflower (Helianthus annuus L.) is one of the most important oil-producing plants in the world. Innovative strategies are needed to improve water and nutrient use efficiencies for sustainable production in sandy soils. In recent years, there has been an increasing demand for agricultural ...
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IntroductionThe sunflower (Helianthus annuus L.) is one of the most important oil-producing plants in the world. Innovative strategies are needed to improve water and nutrient use efficiencies for sustainable production in sandy soils. In recent years, there has been an increasing demand for agricultural products with specific qualities. Oil seeds are the most important sources of energy for human demand following cereals. During recent decades, Cultivation area of sunflower as a main oilseed crop considerably increased due to its short growth season, high oil yield and also its nutritional value. Unsaturated fatty acids such as Oleic, Linoleic acids include about 90% of sunflower oil. Evaluation of different nutrient sources to achieve more drought tolerance in sunflower is vital to achieve high quantity and quality yield. Oil quality and yield are both dependent upon the genotype of a plant and its interaction with the environment. Among the factors responsible for increasing crop yield and quality, irrigation and fertilizer are the most important. Materials and methods In order to evaluate the response of sunflower quantitative and qualitative yield to various nitrogen sources and zeolite under different irrigation regimes, a two-year study was carried out as split-factorial based on RCBD at Agricultural Research Faculty of Tarbiat Modares University in 2015 and 2016. Irrigation regimes including (irrigation after depleting 40, 60, 80% of available soil water (ASW), was considered as main plot while the combinations of the nitrogen sources (providing 100% of required N through manure farmyard, 50% farm yard+ 50% urea, 100% of required N through urea) and zeolite (0, 5 10 t ha-1) were regarded as subplot. Results and discussionThe results showed the highest stem diameter and height in the first (respectively 2/2 mm and 186.7 cm) and second (respectively 2.26 mm and 168.3 cm) years were achieved by using zeolite and irrigation after depleting 40% of ASW. In addition, the highest grain oil and protein yield in second year were obtained by irrigation after depleting 40% of ASW accompanied with using zeolite. Water stress caused significant decline in unsaturated fatty acids including oleic, linoleic, stearic acids (respectively 22 and 7, 50 % in the first and 27, 6.8 and 52 % in the second year) while palmetic acid increased under water stress by 54.6 and 65.3% in the first and second years. Farmyard manure positively affected oil quality in sequential years through higher accumulation of oleic (by 9.2 and 9.7%), linoleic acids (by 7.8 and 8.2%) under water stress conditions. ConclusionsThe result showed that under well irrigated conditions using manure farmyard and under water stress manure farmyard accompanied with zeolite, led to the best results in terms of quantitative and qualitative yield. In general, zeolite application and farmyard manure could alleviate water stress adverse effects, and improved plant growth, yield and oil and protein concentration. Overall, using manure farmyard plus zeolite might be considered as agronomic approach to decrease chemical fertilizer application rates and improve the sustainability of agricultural systems especially when the sunflower plants were subjected to water shortage conditions.
Hassan Ghasemian Ardestani; Mohsen Jahan; Amir Hossein Shirani Rad
Abstract
Introduction Drought stress is the main factor which limits crops production across the world. Selection of crops that are adapted to the climate of each region, the selection of suitable and resistant to environmental stresses, and the use of high-yielding farming practices play an important role in ...
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Introduction Drought stress is the main factor which limits crops production across the world. Selection of crops that are adapted to the climate of each region, the selection of suitable and resistant to environmental stresses, and the use of high-yielding farming practices play an important role in increasing the efficiency of rare source of irrigation water. Morphological and physiological recognition of drought resistance is important for the improvement of problems caused by drought conditions. Materials and methods In order to evaluate the yield and the yield components of selected canola varieties under different temperature and humidity regimes, a factorial split plot experiment was conducted based on randomized complete block design with three replications for two years (2015-2016) in Karaj region. The study site was a field of the Seed and Plant Improvement Institute, Karaj, Iran (35° 59′ N, 50° 75′ E, at the altitude of 1313 m). The main plot factor was included the growing season in two levels (autumn and winter). Irrigation in three levels (normal irrigation or control, Interruption of irrigation from flowering stage and Interruption of irrigation from podding stage) and spring rapeseed cultivars included Jerry, Julius, Zafar, RGS 003, Hayola 4815 and Zabul 10 were assigned to sub plots. Some traits were studied including plant height, slique number and slique length, seed yield, biological yield, 1000seed weight, harvest index. Data were analyzed using the general linear model (GLM) procedure of the statistical analysis system, SAS. When analysis of variance showed significant treatment effects, Duncan’s multiple range tests was applied to compare the means at P < 0.05. According to analysis of variances, treatments and interaction between treatments had significant effect on studied traits at 5 or 1% statistically levels. Results and discussion According to means comparisons, The results showed that in autumn cultivation under control irrigation, the Julius and the Zabol 10 cultivars with dry matter yield of 5592 and 5536 kg/ha, and under interruption of irrigation from flowering stage condition, Julius cultivar with yield of 2511 kg/ha, and in the case of interruption of irrigation from the podding stage, Julius and Zabul 10 cultivars with yield of 4124 and 3959 kg/ha were superior cultivars. In winter cultivation under normal irrigation conditions, the Julius and the Hyola 4815 cultivars with dry matter yield of 3551 and 3307 kg/ha, and the Hyola 4815 and the Zabol 10 cultivars in interruption of irrigation from the flowering stage with dry matter yield of 1595 and 1542 kg ha-1 and in interruption of irrigation from podding stage with 2308 and 2173 kg ha-1 had the highest dry matter yield. ConclusionGenerally, Application of drought stress and winter planting date led to the reduction of yield in all varieties, the results of two years experiment showed that Jolius and Hyolla 4815 cultivars had the highest grain yield under different irrigation conditions. Hyola 4815 cultivar was also suitable for drought stress (interruption of irrigation in both stages). Therefore, these cultivars can be introduced as suitable cultivars in regions may be faced with drought and non-drought stress during the growth period.
Hossein Shirazi; Abbas Biabani; Hossein Saboori; Masomeh Naemi
Abstract
IntroductionRice is the main source of calories in more than one-third of the world's population, increasing by 30 to 35 percent by 2050, according to demand, Iran supplies 50 percent of imports of rice, the import figure in 1993 was about 185 million tons worth one billion and four hundred and ten million ...
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IntroductionRice is the main source of calories in more than one-third of the world's population, increasing by 30 to 35 percent by 2050, according to demand, Iran supplies 50 percent of imports of rice, the import figure in 1993 was about 185 million tons worth one billion and four hundred and ten million dollars (Jedari, 2017). Drought is the most important limiting factor in rice production in 40 million hectares of rice cultivated land in Asia (Ghiasi et al., 2014). Water stress during the vegetative stage reduces the buds; if the stress at the reproductive stage and grain filling causes a decrease in the number of seeds and weight (Rahman et al., 2002). Water stress in the vegetative stage affects the overall biomass reduction, which results from reduced photosynthetic rates and dry matter weights (Tahmasebi et al., 2008). Due to lack of water resources, low irrigation efficiency in rice field, the necessity of increasing water productivity and sensitivity of rice plant to drought stress. In this research, the effect of low irrigation management on morphological traits and yield of rice varieties, as well as determining the best level of irrigation for production Desirable performance in rice varieties has been evaluated. Materials and methodsIn order to investigate the effect of irrigation management on morphological traits and yield of rice cultivars, four separate experiments were carried out in a randomized complete block design in a research farm of GonbadKavus University in 1395. Four experiments were carried out separately in 5, 10 and 15 days irrigation and irrigation periods. The irrigation treatments were applied for 40 days after planting in the field at maximum tillering stage. The second factor also includes six rice cultivars (An Iranian cultivar Domsiah and three cultivar IR66424–1-2–1-5، IR70360–38–1-B-1, IR 55411-50 and the two lines are being introduced 87.110 and 87.5.103). Morphological traits included : 1- Main cluster length, 2- Plant weight, 3- Leaves number, 4- Plant Height As well as yield and yield components including number of tillers per plant, number of pods in the main cluster, number of filled seeds in the main cluster, Fertility percentage, full grain weight in main cluster, grain weight per plant, grain yield and harvest index As well as the number of days to be considered. FindingsAnalysis of variance showed that there is a significant difference between all experimental treatment levels. Exerting stress reduces grain yield. The mean comparison results in terms of flood waters showed a cultivar of 87.110, Minimum time to treat and grain yield, which had no significant difference in grain yield in comparison with native damsayah cultivar. In drought stress, 5 days the highest grain yield and the lowest number of days till the cultivar was 87.5.103 was observed. Grain yield in 10-day irrigation stress was significant in IR 55411-50 cultivar compared to other cultivars. Also, the results showed that the figure 87.5.103 was early childhood. In the irrigation round 15 days, while the figure is 87. 110 did not have the highest grain yield, However, there was no significant difference between Damsayeh variety, Also, the Cultivar 87.110 is the earliest and best cultivar in the region.
Nadia Gharechaei1; Farzad Paknejad; Hosein Shirani Rad; Ghasem Tohidloo; Hamid Jabbari
Abstract
Introduction Selection of crops that are adapted to the climate of each region, the selection of suitable and resistant to environmental stresses, and the use of high-yielding farming practices play an important role in increasing the efficiency of rare source of irrigation water. The aim of this study ...
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Introduction Selection of crops that are adapted to the climate of each region, the selection of suitable and resistant to environmental stresses, and the use of high-yielding farming practices play an important role in increasing the efficiency of rare source of irrigation water. The aim of this study was to evaluate the reaction of rapeseed genotypes to end-stage drought stress in delayed planting conditions. Material and Methods This study was performed to evaluation of late season drought stress on agronomic traits of autumn canola genotypes in two temperature planting dates. Experimental design was done as split plot in RCBD design with 3 replications at two years in Karaj province, Iran. In this experiment, the planting date included timely (7th October) and late planting date (27th October) and irrigation including common irrigation and interruption from slique stage in main plots and five canola genotypes consisted of L1030, L1204, L1110, L1114 and one commercial (Okapi) cultivar. Analyses were performed by using the SAS software version 9 By doing bartlett test and after defining it insignificantly (Except 2 case), combined analysis of variance was done and In order to compare the means, Duncan's multiple range test was used at the 5% level. Studied traits included plant height, branch number, slique number, slique length, seed number/slique, 1000seed weight, biological yield, seed yield, harvest index, oil content and oil yield. Results and discussion Results showed that in both planting dates, interruption of irrigation led to the reduction of yield. All genotypes had higher grain yield with 7th October planting date than late planting date and the effect of interaction between planting date and genotype on all traits except harvest index was significant. The highest mean of traits was obtained on the fifth of October and the genotype L1204. The highest mean grain yield (5118 kg ha-1) was attributed to L1204 genotype in the planting date of October 7 and the lowest mean (2297 kg ha-1) was allocated to L1114 genotype on planting date of 27th October. Highest grain yield were obtained by L1204 at normal irrigation (4733 kg ha-1) and interruption of irrigation (3400 kg ha-1). The highest grain yield in delayed planting condition and stop irrigation after silique stage (2460 kg ha-1) was observed in L1204 genotype. Also, according to results, it was founded that all treatments had significant effects on oil content and the highest oil percentage (44%) was obtained by L1204 genotype. Interaction effect of evaluated genotypes with planting date showed that all genotypes had higher mean at 7th October planting date, and the highest mean oil percentage (44.18%) was observed by L1204 genotypes at 7th October planting date and The lowest mean (41. 39%) was allocated to the Okapi genotype at the late planting condition. The highest mean at 27th October planting date (41.83%) was belonged to L1204 genotype. Conclusion Application of drought stress and late planting date led to reduction of yield in all genotypes but these reductions were less by L1204 genotype in compared to other genotypes.
Zahra Tahmasebi; Hossein Mohammadi dehbalaee
Abstract
Introduction Black beans are a variety of common beans (Phaseolus vulgaris) and belong to the legumes. Black beans contain a wide range of flavonoids, as well as some phenolic acids. The problems of production of this product, which reduces yields, are non-biological stresses, including drought. About ...
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Introduction Black beans are a variety of common beans (Phaseolus vulgaris) and belong to the legumes. Black beans contain a wide range of flavonoids, as well as some phenolic acids. The problems of production of this product, which reduces yields, are non-biological stresses, including drought. About 60% of the world's cultivateted bean is at risk of intermittent drought or at the end of the season. Several indices have been proposed to assess the response of genotypes under different environmental conditions and to determine their resistance and susceptibility, which helps to select drought tolerant genotypes. The aim of this study was to investigate the effect of drought stress on yield and yield components of black bean genotypes and to evaluate the response of these genotypes to drought stress by indices of drought tolerance. Materials and methods 14 bean genotypes including 11 black bean genotypes and 3 other genotypes (which were control genotypes) were obtained from the Gene Bank of Agricultural and Natural Resources department in Karaj in two completely randomized block designs with 3 replications in two adjacent plots In the educational research farm of Ilam University in the city of Mehran was cultivated. In the first experiment, irrigation was carried out as normal and irrigation intervals based on 50 ml evaporation from the evaporation pan. In the second experiment, water stress was applied at flowering stage. At this stage, the irrigation interval was based on 100 ml evaporation from the pan. The measured traits included number of pods per plant, number of seeds per pod, plant height, grain yield and 100 grain weight. After data collection, analysis of variance and mean comparison by LSD method were performed for the studied traits. In addition, in order to determine resistant and stress resistant cultivars, various indices related to stress resistance including SSI (stress susceptibility index), STI (stress tolerance index), TOL (stress tolerance index), MP (average productivity index), GMP (Geometric Productivity Indicator) and Harm (Harmonic Average Index) were calculated. In order to determine the best index, the correlation of genotypes yield under stress condition (YS) and without stress (YP) with drought tolerance index was calculated. Results and discussion The results of combined analysis of the data showed that the effect of environment and genotypes on all traits was significant and the diversity between the studied genotypes was observed in terms of traits under normal and stress conditions. In terms of yield, 1140 and 1170 genotypes had the highest and lowest yields respectively. In general, all traits were changed due to stress and their mean values decreased under stress conditions. The percentage of grain yield under stress was estimated to be 24.26%. The most changes due to drought stress in genotypes related to yield, pod number and plant height. The most changes were due to drought stress in yield, pod number and plant height of black bean genotypes. Based on the Principal Component Analysis on the six indicators, YP and YS in the genotypes evaluated, it was found that the two main components justify 98.9% of the total variation. The first component expresses 68.6 percent of the total variation. The highest positive factor in the linear composition of the first component was YP, YS, MP, GMP, and STI. Based on the analysis of the main components on the six indicators, YP and YS in the genotypes evaluated, it was found that the two main components justify 98.9% of the total variation. The first component expresses 68.6 percent of the total variation. The highest positive factor in the linear composition of the first component was YP, YS, MP, GMP, and STI. Conclusions Based on the findings of this study, yield loss in drought stress conditions in black bean genotypes was mainly due to the reduction in the number of pods per plant. According to correlation of YS and drought tolerance indices, STI, GMP and MP were the best indices of drought tolerance under stress conditions. Therefore, based on these indices, among the genotypes of black beans, 1183 genotype as the most tolerant (with 8.07 g per plant) and genotypes 1187 and 1177 as the most sensitive genotype to drought stress (respectively, with yield 4. 17 and 5.22 g per plant) were selected. Also, control genotypes (256, Talash and Daneshkadeh) had higher yields (respectively 18.72, 13.56 and 14.21 g per plant respectively) and, for most of the indices, were more resistant than black bean genotypes. By using bi-plot of the Principal Component, genotype 1183 selected as the most tolerant drought stress.
Mozhde Aghili Lake; Elias Soltani; Iraj Alahdadi; Fatemeh Benakashani
Abstract
Introduction oilseed rape has a wide range of adaptation and grows well in many regions under variable temperatures. However, the ability of the varieties varies in response to the favorable and unfavorable conditions. Temperature stresses (high or low temperatures) have harmful effects on crops. Generally, ...
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Introduction oilseed rape has a wide range of adaptation and grows well in many regions under variable temperatures. However, the ability of the varieties varies in response to the favorable and unfavorable conditions. Temperature stresses (high or low temperatures) have harmful effects on crops. Generally, temperatures below 10 ° C can damage germination and emergence. Low temperatures can also have a negative effect on the post-emergence stages of crops. The high temperatures can also reduce the total dry matter produced, the number of pods under development, the number of seeds per pod, the weight of seeds, and, finally, the yield of the plant. Also, high temperatures affect the development and maturity of the seeds, resulting in a higher level of yield. Identifying high or low tolerant cultivars can help researchers improve the new cultivars and increase the flexibility of selecting the right cultivar for farmers. There are several methods for evaluating cultivars at low and high temperatures based on farm or laboratory surveys. Field surveys are difficult, unsustainable and seasonal. Because in field conditions, temperatures and humidity fluctuate a lot. Various studies have been done to evaluate the variation of germination in heat or cold stress in different plants such as lettuce, alfalfa, sorghum, cotton, sesame, etc. However, there is not much information on canola cultivars in Iran. The aims of this study was to determine the cardinal temperatures (2) evaluate the tolerance of different genotypes at high or low temperatures and (3) and to study the secondary dormancy potential in Iranian genotypes. Materials and methods In order to, germination tests were conducted in fixed temperatures incubators with 5, 10, 15, 20, 25 and 30 oC on 10 oilseed rape genotypes, in 4 replications with 50 seeds. Finally, cardinal temperatures were estimated using segmented (for germination rate) and beta (for germination percentage) functions. The tolerance of genotypes to high or low temperatures were determined using estimated cardinal temperatures. Also, an experiment was conducted to investigate the potential of different cultivars for induction of dormancy, in which seeds of 10 oilseed rape genotypes were subjected to drought stress conditions to determine the percentage of total induction due to drought for each genotype. The percentage of germinated seeds, the percentage of seeds with dormancy and dead seeds can be determined. Finally, the percentage of induction of the secondary dormancy was calculated for each genotype. Statistical analysis was performed using SAS software. Results and discussion Marshall and Squire (1996) showed that the minimum temperature (Tb) for oilseed rape germination was about 3 °C. Soltani et al. (2013) showed that the minimum temperature for oilseed rape germination was 2.7 °C and under dry conditions up to 6.7 °C at -0.8 MPa increased. Also, they showed that the average thermal time for germination (TT50) increased from 29.5 °C/day at 0 MPa to 57.9 °C/day at -0.8 MPa. Results indicated that mean of base (Tb), optimum (To) and ceiling (Tc) temperatures for germination percentage were 4.99, 18.23 and 34,20 oC and also mean of base (Tb), optimum (To) and ceiling (Tc) temperatures for germination rate were 6.18, 24.76 and 39.40 oC. The Heat and Cold tolerance indexes were also different in different cultivars. Okapi cultivar was the most tolerant in heat tolerance index (5.95) and in cold tolerance index (8.48). X-Power had the lowest tolerance to heat (4.78) and cold (6.50). The potential of secondary dormancy induction also was at the highest level in Okapi (about 40 %). It seems that there was connection between secondary dormancy induction and tolerance to temperature stresses which needs more studies.
Peyman Eynizadeh; Hamid Dehghani; Mostafa Khodadadi
Abstract
Introduction and goals Coriander (Coriandrum sativum L.) is an annual plant that drought stress can impact on its yield. Drought stress is one of the most common environmental stresses limit agricultural productivities. This stress effects on many metabolic pathways such as photosynthesis, water absorption ...
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Introduction and goals Coriander (Coriandrum sativum L.) is an annual plant that drought stress can impact on its yield. Drought stress is one of the most common environmental stresses limit agricultural productivities. This stress effects on many metabolic pathways such as photosynthesis, water absorption and transfer, enzymes’ activity and organic material transfer and accumulation. It can also lead to the accumulation of secondary metabolites in the plant. In the case of some quantitative and qualitative traits, such as the yield and the amount of the essential oil, the selection can be done indirectly with the help of some statistical techniques. This research was conducted to investigation of interrelated traits with fruit yield and fruit essential oil content and also to suggest two multipurpose selection procedures for simultaneous improvement of several traits in all three irrigation regimes by the help of graphical analysis in coriander. Thereafter top landraces based on all attributes for selection and cultivation in the well irrigated, gradual drought stressed and severe drought stressed irrigation regimes were identified. Material and methods Three experiments were carried out based on randomized complete block design with three replications at the Research Farm of Tarbiat Modares University in 2015. In experiments, normal irrigation, severe stress, and gradual stress were applied and combined analysis of variance was performed for 16 physiological, morphological and phonological traits. Genotypic and phenotypic variances, genotypic and phenotypic variation coefficients, heritability in broad sense and genetic progress percentage were calculated. Genotypic and phenotypic correlations were calculated according to Holland, 2006 in combined analysis of variance. Factor analysis using the genotypic correlation matrix of traits and plotting ecotype × trait biplot based on the first two factors, which had the highest correlation with the studied traits, was performed by MATLAB software. Clustering of genotypes and traits based on average traits in three experiments and also based on replication means separately in each experiment using Ward method and Square Euclidean Distance were performed and the corresponding heatmap was plotted using metaboanalyst 3.0 software. Results and discussion Combined ANOVA showed relatively high variation for ecotypes in most traits. The genotype × environment interaction was significant in most of the traits at 1% probability level. The traits of days to 50% of fruit maturity, 1000 fruit weight, fruit yield and relative water content of the leaves had a relatively high environmental impact, and the indices related to the environment had fairly large difference with the ecotype indices. The effect of the environment on the fruit yield was so high that the genetic variance was estimated to be zero. Prematurity related traits had a relatively high genetic variance, and their genetic advance was relatively high. Therefore, selection may be effective to improve these traits under normal and stressed conditions. The highest percentage of genetic advance was observed for traits of leaf chlorophyll and base leaf number. Phonological traits, basal leaf number, plant height, plant dry weight, number of branches, number of umbels, number of fruits per plant, chlorophyll content and essential oil content had a high value of heritability and genetic advance. In factor analysis, the first two factors explained 51.13% and 23.71% of the total variation. The first factor showed existence high genotypic correlation between the most traits with each other, and on the other hand, the second factor showed the correlation between the relative water content of the leaves and the number of days to fruit maturity. According to the obtained biplot, the ecotypes with the highest genetic potential for most of the traits were identified, which were respectively ecotypes 4, 11, 15, 3 and 14. The ecotypes and traits were categorized into three groups according to the heatmap clustering. The observed differences between these two graphical representations in the ecotypic and traits grouping are due to the fact that the biplot is independent of the environmental effects and the genotype × environment interaction, while the heatmap is drawn based on the average of ecotypes in different moisture regimes. Conclusions Selection above mentioned ecotypes and obtain a superior population by them may be useful in simultaneously improving the important economic traits such as the amount of essential oil, basal leaf number and dry weight of biomass in both normal and stress conditions. Prematurity and relatively high value of harvest index in ecotype 9 make it suitable for the second cultivation in endangered areas of drought at the end of the season to produce fruit and essential oil. Ecotype No. 10 had the highest amount of essential oil and number of base leaves, but the lateness of this ecotype caused it to be severely drought sensitive and its average fruit yield reduced in different irrigation regimes. A great similarity was found between the results of the two graphical analysis methods and the traits were well grouped in a method that the combination of irrigation regimes and ecotypes was not considered.
Mehdi Karimi
Abstract
IntroductionSalinity stress is known as a worldwide abiotic stress responsible for reduced crop production. It is estimated that annual losses of yield due to salt induced land degradation is US$ 27.3 billion globally (Qadir et al., 2014). Social and economic dimentions of salinity stress can be employment ...
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IntroductionSalinity stress is known as a worldwide abiotic stress responsible for reduced crop production. It is estimated that annual losses of yield due to salt induced land degradation is US$ 27.3 billion globally (Qadir et al., 2014). Social and economic dimentions of salinity stress can be employment losses as well as environmental degradation (Butcher et al., 2016). In addition, it is well documented that application of chemical fertilizers usually improve plant performance under saline conditons but results in plant fertilizer requirement under salt affected soils are contrary. While there is little evidence of yield benefits due to application of fertilizers in salinized fields at rates beyond optimal in non-saline conditions, there is enough evidence indicating that soil salinity does not affect or decrease plant fertilizer needs (Hanson, 2006). A hypothesis that potassium (K) application can reduce the negative effects of salinity on plant performance has been proposed, but, contradictory results have been reported. These include a reduction in salinity damage to crops when high concentrations of K are present in growth media as well as no response to K fertilizer under salinity or even a negative effect of K addition on salt tolerance (Bar-Tal et al., 1991). These contradictory results can be attributed to the types of experiments (field, greenhouse or laboratory), composition of the saline substrate, studies conducted over the short term vs. the long term and many other differences in experimental conditions (Grattan and Grieve, 1999).Thus K fertilizer management may need to be modified under arid and semiarid conditions of Yazd peovince with wide range of irrigation water qualities. Accordingly, the objectives of this field study were to (a) elucidate the interactions between K nutrition and the salinity of irrigation water and their effects on wheat growth and (b) test the possibility of wheat improvement at saline conditions by applying higher levels of K fertilizer. Materials and methodsA field experiment was conducted on wheat at Sadooq Salinity Research Station, Ashkezar, Yazd, Iran. The soil at the experimental site was calcareous with 30.92% total nutrient value, sandy loam texture, pH 8.06 and 0.22 % organic carbon. Mean annual temperatue is 18°C and precipitation is 70 mm. The treatments, four potassium sulphate application rates (0, 100, 200 and 300 kg ha-1) and three irrigation water qualities (1.88, 7.22 , 14.16 dS/m), arranged in a randomized block, split plot design with three repelications. Consisting 12 rows of wheat, each field plot was 3*5 m. All plots received common agricultural practices including tillage and fertilizer application. Rgarding typical recommendations and guidelines for this region and soil type (Balali et al., 2000: Moshiri et al., 2015), all fertilizers, except urea that applied in 4 splits, were soil-applied before plnating and included 100 kg ha-1 triple superphosphate, 40 kg ha-1 FeSO4, 40 kg ha-1 ZnSO4, 40 kg ha-1 MnSO4 and 20 kg ha-1 CuSO4. To model the relationship between plant properties and irrigation water salinity, the data were subjected to different regression models at the probability level of 0.01 and 0.05 with the help of the Sigmaplot software. The analysis of variance for different parameters was done following ANOVA technique. When F was significant at p ≤ 0.05 level, treatment means were separated using DMRT. Results and discussionThe results showed that increasing irrigation water salinity to 7.22 dS/m did not significantly affect wheat graine yield. This is due to the non-significant effect of salinity on 1000 seed weight, harvesting index and non bearing spikelets in addition to the significant increase in spike length, bearing spikelets, bearing spikelet numbers, seed number per spikes and total spikelet numbers. At the same time, the results showed 50% decrease in wheat grain and straw yield due to the increase in the salinity of irrigation water from 1.88 to 14.16 dS/m. As application of K fertilizer did not affect wheat performance significantly, it was concluded that K application did not increase wheat tolerance to salinity stress under field conditions of our experiment. ConclusionOverall, it was concluded that K fertilizer was not necessary for wheat production (6 Mg ha-1 grain and 9 Mg ha-1 straw) under saline and non-saline calcareous soils of Yazd province with soil available K of 150 mg kg-1. Key words: Calcareous soils, Irrigation Water and Yazd.
Adel Modhej; Azam Karbalaei
Abstract
Introduction Wheat has been planted in saline conditions in many areas of central and southern Khuzestan, and high temperatures at early planting date may exacerbate the effects of salinity. Investigations show that not only different crop species but also genotypes of a species may have a different ...
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Introduction Wheat has been planted in saline conditions in many areas of central and southern Khuzestan, and high temperatures at early planting date may exacerbate the effects of salinity. Investigations show that not only different crop species but also genotypes of a species may have a different tolerance to salinity. Main constructs of tolerant wheat cultivars include the separation of sodium and chlorine in vacuole root and leaf cells. It has also been reported that tolerance cultivars, with osmotic stress in the root environment, have better seedling growth rates. The reason for the difference between the wheat cultivars studied in response to salinity was the ratio of sodium to potassium in the seedling of these cultivars. Seedling tolerant to salinity in wheat has a lower sodium content and higher potassium content than sensitive genotypes. Materials and Methods In order to investigate the effect of salinity and temperature on germination and seedling growth of three genotypes of bread and durum wheat, this experiment was carried out in the laboratory of Islamic Azad University, Khouzestan Research Branch, in 2011 in Petri Dish growing conditions. Factorial experiment was carried out using three temperature treatments (15/10, 25/20 and 35/30 ° C night/ day), wheat genotypes (two bread genotypes of Chamran and 20 Sarasary and Durum Line D85-17) and salinity (0, 2, 4, 8, and 12 ds/m). During the experiment, the germinated seed was considered to have a root length of at least two millimeters. One week after the treatments, from each petri dish, five seeds were selected to measure the traits. The traits of root length, stem and coleoptile, germination percentage, germination rate and sodium / potassium ratio were measured. Results and discussion The results showed that salinity increased germination percentage significantly in wheat genotypes. The maximum and minimum stem length was 25.25 and 35.30 ° C, respectively. With increasing temperature from 15.10 to 25.20 ° C, there was 43% increase in stem length. The increase in temperature from 25.20 ° C to 35.30 ° C reduced the stem length by about 52%. The percentage reduction in the root length of bread wheat cultivars, Chamran, as well as the durum line in 12 ds.m-1 compared to control distilled water were 41.5, 41.1 and 59.5%, respectively. Wheat genotypes at 25/25 ° C had the highest seedling growth. The highest and lowest germination percentages were observed at 15/15 and 35/30 ° C temperature treatments. Line 17-85D in comparison with bread genotypes was more sensitive to salinity and temperature. Increasing ambient temperature exacerbated the effect of salinity on germination and seedling growth. Increasing temperature increased the effect of salinity on plumule length, so that the reduction in plumule length under salinity of 12 dS/m and 15/35, 25/20 and 35/30° C temperature treatments, was 33.3, 50 and 84 percent respectively. Na+/K+ ratio was higher in wheat genotypes at high temperatures. Durum line D85-17 had a higher Na+/K+ and sensitivity to salinity compared to two bread genotypes. Conclusions According to the results, sodium and potassium ratio index was a suitable criterion for evaluating reaction of genotypes to salinity in temperature treatments. The Durum line was more susceptible to salinity and two bread genotypes were more tolerant to salinity due to less sodium accumulation and a higher sodium to potassium ratio. Meanwhile, genotypes such as Chamran, with more tolerance to the temperature, had less susceptibility to salinity. In general, it was recommended that in order to increase the accuracy of the research, the response of other wheat genotypes to salinity and temperature should be studied.
Maedeh Bohlouli; Maryam Dehestani-Ardakani; Mostafa Shirmardi; Jamshid Razmjoo
Abstract
Introduction Salinity is an important environmental tension limiting growth and productivity of plants worldwide. About 7% of the world’s total land area is affected by different degrees of salinity. Saline soil can be defined as soil having an electrical conductivity of the saturated paste extract ...
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Introduction Salinity is an important environmental tension limiting growth and productivity of plants worldwide. About 7% of the world’s total land area is affected by different degrees of salinity. Saline soil can be defined as soil having an electrical conductivity of the saturated paste extract (ECe) of 4 dSm−1 (4 dSm−1 ∼40mM NaCl) or more. The harmful effects of high salinity on plants can be observed in different levels such as the death of plants or necrosis of plant organs and/or decreases in productivity. Some tolerant plants develop mechanisms either to exclude salt from their cells or to tolerate its presence within cells. Major processes such as photosynthesis, protein synthesis, and energy and lipid metabolism are affected in plants during the beginning and development of salinity stress.Oenothera biennis L., an important medicinal plant, known as evening primrose. Organic fertilizers develop favorable physical, chemical and biological environment in the soil. They stimulate plant root growth, increase nutrient uptake and soil water-holding capacity, decreases evaporation from the soil and surface water runoff, facilitate drainage, regulate soil temperature and provide a rich substrate for soil microbes. This study was conducted to determine the effects of soil salinity and organic amendments on some growth characteristics, concentration of phosphorus, sodium and potassium and catalase enzyme activity in evening primrose plant (Oenothera biennis L.). Material and methods In a factorial experiment and completely randomized design (CRD), six levels of organic amendments (control (without soil amendments), 1.5 and 3 g.L-1 mycorrhizal fungi, 16 and 32 mg l-1 humic acid and 25% v/v madder residue plant) and three levels of soil salinity (4, 7 and 12 dS.m-1) with three replications per treatments were applied in Mahmoodabad research field of Esfahan municipality. In this experiment, media without organic amendment was considered as control. Results and discussion Results showed that increasing soil salinity levels progressively decreased the growth characteristics and nutrients concentration. Salinity causes growth reduction due to the low osmotic potential of the medium and by a specific ion effect as a secondary cause in several vegetable crops. The results of present study showed that the organic media can improve plant height. This can be due to increased media moisture storage and enhanced nutrient absorption. In EC = 4 dS.m-1 the highest plant height, root length and P concentration obtained in plants treated with 3 g/kg mycorrhizal fungi. Where in 7 and 12 dS.m-1 salt, organic matter showed the best effect on relative water conductivity, reducing time to flowering, increasing the P and K concentration, fresh and dry weigh of root and shoot, also ratio of dry weight to fresh weight. Mycorrhizal treatment in 7 dS.m-1 showed the highest root length. In 12 the most dry weighet of root, ratio of dry weight to fresh weight, the number of active leaves and K concentration in 16 mg/l humic acid and the most number of active leaves, chlorophyll and the lowest concentration of Na obtained in madder residue plant. Also madder residue plant reduced Na concentration in 7 and 12 dS.m-1 levels. In 12 dS.m-1 plants didn’t show reproductive phase, but adding soil amendments caused flowering induction. Excess soluble salts in the root zone restrict plant roots from withdrawing water from surrounding soil, effectively and causes drought for the plant. The loss of photosynthesis in salt stress condition resulted in the loss of dry weight production at the leaf level of evening primrose. Generally, all treatments in all salt levels caused increasing growth and yield of plant. Conclusion According to the results, it is cleared that in normal condition, evening primrose plant could tolerate salt stress until 7 dS.m-1 but by suitable media culture its threshold tolerate will be increased until 12 dS.m-1. Also it was revealed that all treatments could increase plant tolerate to salt stress and growth characteristics.
Reyhane Pordel; Mohammad Kafi; Masoud Esfahani; Ahmad Nezami
Abstract
IntroductionStevia rebaudiana Bertoni in an ancient perennial shrub of South America, produces diterpene glycosides that are low-calorie sweetener sand about 300 times sweeter than saccharose (Savita et al., 2004). Stevia extracts, besides having therapeutic properties, contain a high level of sweetening ...
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IntroductionStevia rebaudiana Bertoni in an ancient perennial shrub of South America, produces diterpene glycosides that are low-calorie sweetener sand about 300 times sweeter than saccharose (Savita et al., 2004). Stevia extracts, besides having therapeutic properties, contain a high level of sweetening compounds, known as steviole glycosides, which are thought to possess antioxidant, antimicrobial and antifungal activity. Stevia cultivation and production, especially in Iran, would further help those who have to restrict carbohydrate intake in their diet; to enjoy the sweet taste with minimal calories. In Iran, the best area that has the most similarity of favorable climate condition for Stevia cultivation is the north of Iran. However, poor soil aeration associated with excessive moisture usually influences plant establishment and growth negatively in this part of Iran. Heavy textured soils in northern regions of Iran are more susceptible to waterlogging after heavy rain, and hypoxia is likely to limit Stevia growth. Thus waterlogging is considered as one of the important limiting factors for Stevia cultivation in such regions. On the other hand, Oxidation-reduction systems in the soil, which are generally stable as long as the soil is bathed in oxygen, become unstable when the oxygen supply is restricted. Nitrate is stable in well-aerated soils but become unstable when the oxygen supply of the soil is cut off. Nitrogen is subjected to loss through denitrification because of the ability of facultative anaerobes to substitute nitrate for oxygen. Advantage can be taken from the reducing conditions in waterlogged soils to increase the utilization of nitrogen fertilizer. The objectives of the present experiment were to investigate the effects of waterlogging stress and the alleviation of the waterlogged damage by the application of nitrogen fertilizer in Stevia. Material and methodsA greenhouse pot experiment was conducted in University of Guilan, in 2013. The experimental design was factorial using completely randomized design layout with three replications. Treatments included four waterlogging levels; (0, -5, -10 cm from soil surface and normal irrigation as control), in periods of 2 and 4 days of waterlogging and two levels of nitrogen (6‰ and no nitrogen spraying as control) by foliar spraying from source of urea. Because the economic organ of Stevia is its leaves samples were taken before flowering stage. Results and discussionResults showed that measured shoot traits including leaf percentage, leaf area density, specific leaf weight, leaf dry weight, leaf area, plant height, number of lateral branch, number of leaves were significantly different among treatments. Nitrogen application improved plant height (14%) (Bakhshandeh et al., 2016) but deceased leaf area density (14%) compared with control. Interaction of waterlogging duration and nitrogen fertilizer significantly influenced leaf percentage, specific leaf weight and leaf dry weight. During water logging period increase from two to four days, nitrogen application improved leaf percentage by 4.5%, specific leaf weight by 11%, and leaf dry weight by 14%. In addition, interaction between water logging level and nitrogen application significantly influenced specific leaf weight, number of lateral branch and leaf dry weight. For specific leaf weight in -5 cm water logging level, nitrogen fertilizer application resulted in 12% increase compared with the same water logging level but without nitrogen fertilizer. Nitrogen application under -10 cm water logging level improved the number of lateral branches by 9% compared with complete water logging level without nitrogen application. Also for leaf dry weight, nitrogen application under -10 cm water logging effect resulted in 11% increase compared with no nitrogen application. Generally, the results of this experiment show that nitrogen application under water logging stress improved growth features of Stevia although water logging stress reduce growth characteristics of Stevia. Nitrogen application under the highest waterlogging level improved leaf dry weight by 10% compared with no nitrogen application treatment. Because economic part of Stevia is its leaves, it is likely that nitrogen application under water logging stress improve this trait (Rashid et al., 2013). ConclusionResults of this experiment showed that although level and duration of flooding stress caused a reduction in stevia leaf production but nitrogen application can ameliorate the negative effects of the stress on this trait. Since leaf dry weight is the economical yield of stevia, N application will improve yield if this plant under flooding stress
basir Atarodi; Amir Fotovat; Reza Khorassani; Payman Keshavarz
Abstract
Introduction Agricultural soils in Iran, as in many other countries, are slightly to moderately contaminated by cadmium. According to some published reports, the average content of cadmium in some agricultural products and soils of Iran was found to be above the FAO/WHO guidelines. Abiotic stresses including ...
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Introduction Agricultural soils in Iran, as in many other countries, are slightly to moderately contaminated by cadmium. According to some published reports, the average content of cadmium in some agricultural products and soils of Iran was found to be above the FAO/WHO guidelines. Abiotic stresses including cadmium stress can lead to overproduction of reactive oxygen species (ROS) causing progressive oxidative damage and ultimately cell death. In order to reduce cadmium-induced toxicity and alleviate some adverse effects of this metal on plants, a number of strategies including phytoremediation have been developed. Meanwhile, it was found that application of some elements such as calcium could diminish adverse effects of heavy metals in plants. In addition to calcium, selenium due to its potential in mitigation of cadmium toxicity has gained increased attention in recent decades. Selenium, as an antioxidant, plays an important role in the maintenance of human health, and on the other hand, many soils and, consequently, the crops produced in them suffer from the deficiency of this element. Although some studies have reported protective roles of selenium in plants subjected to cadmium stress, due to the limited reports on the effects of selenium on wheat exposed to cadmium stress particularly under Iranian soils conditions, the present study was conducted. Materials and methods In winter 2015, a pot experiment was carried out based on a completely randomized design in factorial arrangement with three replications for each treatment at research greenhouse of agriculture faculty of Ferdowsi university of Mashhad, Iran. The site is situated at 36°2′ North latitude, 59°4′ East longitude at an altitude of 999.2 m above mean sea level. The experiment included four levels of selenium (0, 0.5, 1, and 4 mg kg -1 soil, in the form of sodium selenite) and three levels of cadmium (0, 5, 15 mg kg -1 soil, in the form of cadmium nitrate). Soil weighing 6 kg was put into polyethylene pots, irrigated with distilled water to field capacity each three days and left over for 45 days to attain equilibrium. Eight seeds of wheat (Triticum aestivum L. cv. Falat) were sown per pot and thinned to four plants after the seedlings of wheat were well established. Sixty days after germination, newly expanded leaf samples from each pot were taken for determination of leaf pigments, proline and enzyme activity. Meanwhile, shoots from each pot were harvested from 1 cm above the soil and rinsed four times (twice with distilled water, once with 20 mM EDTA and again once with distilled water). The samples were wiped with paper and oven-dried at 50 °C for one week. Finally, dry weight of the shoots was measured. Results and discussion Cadmium stress, selenium application, and their interactions had a significant effect on photosynthetic pigments concentration, proline content, catalase activity and shoot dry weight. Results showed that as cadmium concentration in soil increased, chlorophyll a, b concentration, carotenoids content, catalase activity and shoot dry weight decreased. In contrast, the accumulation of proline in the plants was stimulated after the cadmium treatment, by 25 % in the presence of the highest cadmium level, as compared to the lowest cadmium level. Selenium application exerted its positive influence on some physiological parameters in plants exposed to cadmium stress. Chlorophyll b concentration and enzyme activity were higher in plants treated simultaneously with selenium and cadmium as compared with plants treated solely with cadmium. However, selenium did not show positive effect on chlorophyll a concentration, carotenoid content and shoot dry weight in plants grown under cadmium stress. Meanwhile, selenium at high concentration had no beneficial effect on wheat but also led to a significant decrease in photosynthetic pigments content, enzyme activity and shoot dry weight. Conclusions The results of the present study revealed that cadmium stress negatively affected physiological parameters of wheat and decreased photosynthetic pigments concentration, catalase activity and shoot dry weight. In contrast, selenium supplementation at low concentration could improve partially some physiological responses in wheat under cadmium stress.
Zahra Ghorbanpoor; Ahmad Gholamalizadeh; Amir Lakzian; Abolfazl Abbaspoor
Abstract
Introduction The increase in population and the increase of scientific and technical knowledge and the development of industries without observing environmental issues and standards has contributed to the pollution and collapse of the soil biomass balance. Cadmium is a heavy metal, an inessential and ...
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Introduction The increase in population and the increase of scientific and technical knowledge and the development of industries without observing environmental issues and standards has contributed to the pollution and collapse of the soil biomass balance. Cadmium is a heavy metal, an inessential and toxic element for plants that it enter to the earth by different human activities. Phytoremediation is one of the more efficient proposal methods in pollution effacement. The advantage of Phytoremediation is adding organic, nutrient elements and oxygen to the soil that improve the quality and structure of the soil in purging places. Plants also, create a cover for the soil and their roots stabilize the soil and thus reduce the wind and water erosion. There are reports about potassium fertilizer with plants for absorption of cadmium and Phytoremediation preferment. The cadmium ion can formed by permanent complexes with chloride quickly. Chlorides are very fluid and can be an important factor in cadmium distribution of the soil in the specific conditions. The aim of this research is investigation the effect of using chloride and potassium sulfate fertilizer to absorption of cadmium and Phytoremediation preferment by canola plant. Materials and Methods This research performed into factorial and completely random design with 4 potassium levels (0, 100, 200 and 300 mg/gr K2O) from sources of potassium chloride and potassium sulfate, separately and 3 levels of cadmium (0, 15 and 30 mg/kg) from the source of cadmium nitrate in 3 replications at canola plant in glasshouse of center research. Results and Discussion As far the results of analysis of variance of effects of Cadmium and Potassium fertilizers and their interaction have significant effect on the amount of Cadmium of root and shoot, root dry weight and Potassium of root. Also, according to the results, the main effects of cadmium and potassium fertilizers have significant effect on dry weight and Potassium of shoot, whereas the effect of their interaction on dry weight and Potassium of shoot isn’t significant. In the treatment of 15 mg/kg, at 200 and 300 mg/gr levels of Chloride Potassium and 300 mg/gr level of Potassium sulfate into control, increase the content of Cadmium of the root but the content of Cadmium in shoot in 200 and 300 mg/gr levels of Chloride and Potassium sulfate into control increase significantly. The results of interactions in levels of Cadmium and Potassium fertilizers on dry weight of root show that highest amount of the dry weight of root exists in 0 Cadmium treatment (control) in 200 mg/gr level of Potassium sulfate and the lowest amount of dry weight of root has been observed in 30 mg/Kg Cadmium treatment on 300 mg/gr Potassium sulfate level. Highest and lowest amount of dry weight of shoot is related to the control treatment of Cadmium and 30 mg/Kg Cadmium treatment respectively. Also the result of Cadmium treatment shows that the Potassium of shoot decrease significantly with increasing of Cadmium and all levels shows the significant reduction. Highest and lowest amount of Potassium of shoot is related to the 0 level of Cadmium and 30 mg/Kg level of Cadmium respectively. Investigation of the levels of Potassium fertilizers show that adding Potassium fertilizer increase the absorption of the Potassium of shoot has been observed in 300 mg/gr level of Potassium sulfate. Conclusion In this research, there is significant difference between Potassium fertilizers (sulfate and chloride Potassium), whereas highest amount of the absorption of Cadmium has been observed in 300 mg/gr level in chloride Potassium, so according to the results of the glasshouse experiment, the efficiency of Phytoremediation improved however continuity of researches seem to be imperative in the farm conditions
Omid Sadeghipour
Abstract
Introduction With increasing population and the intensification of industrial, urban and agricultural activities, the concentration of heavy metals in agricultural soils is also increasing. Lead (Pb) is one of the most toxic heavy metals that severely limit the crops growth and productivity. Exogenous ...
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Introduction With increasing population and the intensification of industrial, urban and agricultural activities, the concentration of heavy metals in agricultural soils is also increasing. Lead (Pb) is one of the most toxic heavy metals that severely limit the crops growth and productivity. Exogenous application of some compatible solutes such as proline and glycine betaine is one of the effective methods for improving plants tolerance to abiotic stresses. Although much research has been done on the effect of proline and glycine betaine application on increasing the tolerance of different plants to abiotic stresses, including heavy metals, however, there is very limited information about the comparison of the application of these compatible solutes on improving common bean tolerance to Pb toxicity, therefore, the present experiment was designed and carried out. Materials and methods In order to comparison study the effect of proline and glycine betaine application on Pb stress tolerance of common bean plant, a pot experiment was done at the spring and summer of 2015 in south of Tehran. This research was conducted as a completely randomized design with 6 treatments and 4 replications. The treatments included the following levels: Control (no Pb, proline and glycine betaine); Pb stress (500 mg lead nitrate kg-1 soil); Pb stress + seed priming with 25 mM proline; Pb stress + seed priming with 50 mM proline; Pb stress + seed priming with 25 mM glycine betaine; and Pb stress + seed priming with 50 mM glycine betaine. Results and discussion The results of this study showed that Pb stress increased root Pb concentration and oxidative damage to common bean plants. Pb toxicity also reduced the chlorophyll value, relative water content (RWC), plant height, leaf area and root and shoot biomass. However, under Pb stress conditions, seed treatment with proline or glycine betaine reduced Pb uptake, increased activity of antioxidant enzymes and declined oxidative damage, which improved the chlorophyll value, RWC, plant height, leaf area and root and shoot biomass. There were no significant differences between proline and glycine betaine treatments. Conclusions According to the findings of this study, seed priming with proline or glycine betaine by reducing Pb uptake, increasing the activity of antioxidant enzymes, chlorophyll value, and plant water status, can be used as a beneficial method for improving tolerance of common bean to Pb stress.
Volume 12, Issue 1 , April 2019, Pages 330-330
