E. Shirmohammadi; H.A. Alikhani; Ahmad Ali Pourbabaee; H. Etesami
Abstract
Introduction: Stresses of drought, salinity and deficiency of nutrients especially phosphorus (P) are the most important challenges for wheat production in Iran. One of the ways to achieve more wheat yield production is increasing of this plants tolerance to stresses of water-deficit, salinity and deficiency ...
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Introduction: Stresses of drought, salinity and deficiency of nutrients especially phosphorus (P) are the most important challenges for wheat production in Iran. One of the ways to achieve more wheat yield production is increasing of this plants tolerance to stresses of water-deficit, salinity and deficiency of essential elements such as P; and/or alleviate destructive effects of these stresses. In this respect, use of PGPR can be useful. Research has shown that PGPR with multiple mechanisms reduces the negative effects of water-deficit and salinity stresses, and also increases the resistance of plants to these stresses, which ultimately leads to increase of plants growth. This study was designed and carried out to investigate the effect of three superior PGPR on qualitative and quantitative indices of wheat under water-deficit stress in saline soil. Materials and Methods: The soil used in this experiment was collected from longitude of 49° 26' 25'' E, latitude of 35° 52' 26'' N and elevation of 1534 m (located in the Qazvin province of Iran) from depth of 0-30 cm of soil. According to the experimental design, 3.5 kg of soil with applying P-fertilizers treatments was filled to the pots. The factorial arrangement based on completely randomized design (CRD) was used in this study. The treatments were replicated three times. The first factor: soil water content at two levels including 80% and 55% FC (W80 and W55); the second factor: Bacterial inoculants at four levels including control or non-inoculated seeds with bacterium (B0), inoculated seeds with Bacillus pumilus strain W72 (B1), inoculated seeds with B. safensis strain W73 (B2), inoculated seeds with Staphylococcus succinus strain R12N2 (B3); and the third factor: P-fertilizers at six levels including control or non-treated plants with P-fertilizers (F0), and plants treated with (rock phosphate) RP - (F1), RP + 19 mg triple superphosphate (TSP) / kg of soil (F2), RP + 38 mg TSP / kg of soil (F3), RP + 57 mg TSP / kg of soil (F4), with 57 mg TSP / kg of soil (F5), generally there were 144 experimental units (pots). Also, 192 mg RP (containing 13.8% P2O5 or 6.13% P) was mixed per kg of soil in each of RP treatments. Statistical analysis of data was performed using SAS software and comparison of means was evaluated by using the Tukey's test (HSD) at p < 0.05 level. There were 5 plants in each pot and irrigated up to 80% FC with distilled water. With the beginning of stem elongation stage, water-deficit stress was applied and continued until the harvest. During the experiment, pots were kept in greenhouse at 25/20±2°C day/night temperatures and 16 h photoperiod with 23,000 lux light intensity. At the end of the experiment, plants height, fertile clusters, root dry weight /shoot dry weight ratio, total dry weight of plant, grain number, thousand grain weight, also, root, shoot and grain P-concentration were measured. Results and Discussion: Generally, it can be said that the moisture level of W80 compared to W55 increased all of measured traits in wheat plant. Due to the unique properties of water and its role in biological and non-biological reactions, by reducing soil water content to near of the permanent wilting point (W55), water absorption by the plant hardly occurs. Therefore, the plant needs to consume more energy for water absorption or grow with less water than normal status, which these factors disturb the metabolism of cells and eventually decreases natural activity and growth of plant. Also, it seems that under water stress condition, wheat plant by formation of “Rhizosheaths” around of their own roots, enters to the defensive phase and by this strategy prevents expansion of their own rhizosphere. With attention to the special importance of the rhizosphere in the supply of water, nutrients and activity of microorganisms, as well as the effect of microorganisms secretion and root exudates on the solubility and availability of nutrients. Thus, it is reasonable that qualitative and quantitative traits of plants decrease by reduction of the rhizosphere diameter due to the water-deficit stress. There was no significant difference between application of rock phosphate and control (F0) for most of measured traits of soil and plant; but, application of RP with bacterial treatments (B1 and B2 at W80 and B3 at both level of W55 and W80) compared to the control, often increased measured traits. Also, each level of TSP compared to the control, often increased this trait. Research indicates that RP can be used as a P-fertilizer, but its efficiency depends on its reactivity in the soil. There is ample evidence that RP has not enough efficiency in neutral and alkaline soils; but, it can be used as the P-fertilizer with proper efficiency in acidic soils or alkaline soil with application of PGPR. Often, all of three bacterial treatments (B1, B2 and B3) at level of W80 and B3 treatment at level of W55, compared to control (without bacterial inoculation) improved qualitative and quantitative traits of plant. Research also shows that under stressful and non-stressful conditions, PGPR can improve plant growth by different strategies. However, this microorganism does not always improve plant growth under all conditions. It seems to be due to differences in genetic and function of bacteria and with conditions change, each bacterium may behave differently. Conclusions In general, for wheat cultivation that may get exposed to moisture stress at one or more stages of its growth (such as dry-farming of wheat), the use of B3 bacterial inoculant (Staphylococcus succinus strain R12N2) seems appropriate for crop management. Because in this study at both W80 (non-water-deficit stress) and W55 (severe water-deficit stress) levels of soil water content, B3 treatment increased qualitative and quantitative of wheat traits. In other words, because of the natural conditions of the dryland farming, the probability of precipitation is different; it seems that B3 treatment can increase wheat production under these conditions. However, the use of this bacterium as a biofertilizer for dryland wheat farming in Iran or other place of the world requires further testing and evaluation in dryland farms of that countries.
A. Hemati; H. A. Alikhani; M. Rasapoor; H. Asgari Lajayer
Abstract
Introduction: Recycling organic wastes has vital roles in sustainable agriculture, reducing pollutants in the environment, and nutrient enrichment of soils. Compost is the product of recycling organic waste through anaerobic treatment, which can be a good alternative.Again the use of chemical fertilizers ...
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Introduction: Recycling organic wastes has vital roles in sustainable agriculture, reducing pollutants in the environment, and nutrient enrichment of soils. Compost is the product of recycling organic waste through anaerobic treatment, which can be a good alternative.Again the use of chemical fertilizers is inappropriate. Vinasse is brown material and it is a product of industrial production of alcohol from molasses. Vinasse, a by-product of ethanol production from molasses, is a highstrength effluent with a high content of organics, mainly organic acids, reducing substances, cultured matter and glycerol. The wastewater is characterized by high concentrations of potassium, calcium, chloride and sulphate ions, a high content of suspended solids, a high CoD (Chemical oxygen Demand) level and a high temperature at the moment of generation.Vinasse can be used as a supplement for enhancing compost fertilizer quality, because it has plenty of organic matter and minerals. This research was done with the purpose of surveying application of vinasse in different levels on indices of compost producing (temperature, microbial population, nitrogen, carbon, the ratio C/N, nitrate, pH and EC) and producing time in different phases (during the production and after compost production) for 5 months in the waste resumption complex of Aradkooh in Tehran.
Materials and Methods: The method used for compost production from solid waste material was ventilating the fixed mass. In this research, the volume of ventilation was 0.6 lit air for 1 lit waste material in a minute.Four different treatments (each three replicates ) were applied to the compost:C0 without vinasse (control), C1, C2 and C3, respectively 10, 20 and 30 ml vinasse per kg waste material. The following factors were measured during each phase: Total-N was measured by the Kjeldahl method and organic carbon was measured by the Walkley-Black method. Thermometers were used for temperature monitoring at different locations in the riff-raff. The microbial population size was obtained by the CFU method.Electrical conductivity and pH of the water extracts from the samples were determined by shaking the samples mechanically with distilled water at a solid-to-water ratio of 1:10 (w/v). Additionally, NO3–N was determined by spectrophotometric method.
Results and Discussion: At the beginning of this study, theresults showed that, after the formation of the riff-raff, temperature was increasing rapidly all over the riff-raff, which indicates a specified microbial activity. Minimum time to reach the thermophilic temperature, 30 ml per kilogram of vinasse raw materials, was for (C3) and maximum of them was for the control treatment (C0). Adding vinass in the second phase led to an increase in the compost mass temperature. Treatment C3 with the highest and treatment C0 has the lowest microbial populations. Total nitrogen content increased during composting of the waste materials in comparison with its initial concentration. In both phases treatment C3 has the highest and treatment C0 has the lowest total nitrogen content. According to results of the measurements of organic carbon in the first phase, at the beginning of composting process, most of the organic matter was in treatment C3and the lowest organic matter was in C0. However, with increasing the composting process, the vinass treatment had lost jts organic carbon with more gradient. In the second phase by adding vinass, the originally organic carbon increased because of the high levels of organic matter. But,with further vinass treatment, they lost their organic carbon more vigorously. During five months,changes in the ratio of carbon to nitrogen C/Nwas variable. In vinass treatment, the ratio ofC/N increased more vigorously until it reached one quarter and then it fell less sharply. In the first month, this ratio fell less sharply in the control group, and in the final months it fell with more intensity. In the second phase, decreasing the ratio of carbon to nitrogen was observed and the decrease treatment was more than the other treatments. The monthly analysis of riff-raff samples showed that the higher increase in pH mostly occurs in the first month, and in all cases the value of the electrical conductivity increased during composting. Until the second month of pH and EC treatment, C3 and C2 increased and decreased in the third to fifth months.In the second phase pH at vinasse treatment increased and pH at C0 treatment decreased. Maximum amount of nitrate was observed at C3 treatment and at Epsom salt phase nitrate has the maximum amount.
Conclusion: Eventually, it is recognized that treatment C3 and C2it is adequate to add context of organic waste and this treatment decreases the production time of compost up to two months.The second phase was not suitable compared with the first phase due to the inability of increasing nitrate-nitrogen and pH.
E. Malekzadeh; H.A. Alikhani; Gh.R. Savaghebi; M. Zarei
Abstract
Abstract
In this study, interaction between AMF (G. mosseae and Glomus spp., respectively indigenous and non-indigenous of HM-contaminated areas) with Cd-resistant PGPRs (Bacillus mycoides and Micrococcus roseus, indigenous of contaminated areas) on the growth, Cd and nutrient uptake of maize plant ...
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Abstract
In this study, interaction between AMF (G. mosseae and Glomus spp., respectively indigenous and non-indigenous of HM-contaminated areas) with Cd-resistant PGPRs (Bacillus mycoides and Micrococcus roseus, indigenous of contaminated areas) on the growth, Cd and nutrient uptake of maize plant (Zea mays L.) in Cd polluted soil were investigated. With increasing levels of Cd, shoot and root dry weights, shoot Fe and P contents decreased but root and shoot Cd content increased. Root colonization was varied at different levels of Cd and co-inoculation with PGPRs. G. mosseae treatment had greatest amount of shoot and root dry weight, Fe and P of shoot at high concentration of Cd. At the levels of 100 and 200 Cd, in only mycorrhizal treatments, plants colonized by Glomus spp. and G. mosseae had respectively high content of Cd roots. At both levels of Cd, shoot Cd content in co-inoculation of M. roseus and B. mycoides with G. mosseae increased and decreased respectively in comparison with single inoculation of G. mosseae. While, at the levels of 100 and 200 Cd, shoot Cd content in co-inoculation of PGPRs with Glomus spp. respectively increased and decreased/did not significant different compared to single inoculation of Glomus spp. Co-inoculation of G. mosseae and M. roseus, with maximum Cd-accumulated in plant, was the most effective treatment in Cd phytoremediation and stabilization.
Keywords: AM fungi, Plant growth promoting rhizobacteria, Phytoremediation, Cd and maize
H. Etesami; H.A. Alikhani
Abstract
Abstract
Now, it’s completely proved that we can find strains among many strains of each rhizobial group that can also do effective process in plant growth promoting as plant growth hormones production (IAA), in addition of their ability in N2 fixation .therefore, the aim of this research is to determinate ...
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Abstract
Now, it’s completely proved that we can find strains among many strains of each rhizobial group that can also do effective process in plant growth promoting as plant growth hormones production (IAA), in addition of their ability in N2 fixation .therefore, the aim of this research is to determinate the ability of IAA production of some of the indigenous rhizobial strains by two quantitative and qualitative methods. The results obtained from this study show that Rhizobial bacteria enable to produce auxin hormone (IAA). Moreover, this ability is not the same among various rhizobial species and among the strains belonging to each rhizobial species (p3), Rhizobium leguminosarum bv. Viciae (with HD/CD = 2.5 – 3) and Sinorhizobium meliloti (with HD/CD = 2 – 2.5) had the same production ability in both methods and also the strains of Mesorhizobium ciceri (with HD/CD= 1.5 – 2) and Bradyrhizobium spp (with HD/CD= 1 – 1.5) produced the small amount of IAA in both two methods.
Keywords: Rhizobbium, PGPR, IAA, Auxin, Tryptophan
