جستجوی مقالات مرتبط با کلیدواژه « ریزوبیوم » در نشریات گروه « آب و خاک »

Current study was carried out by the aim of investigating the effect of rhizobium bacteria and arbuscular mycorrhizafungi on yield and micronutrients concentration on bean under different irrigation regimes in 2016 and 2017 years.In a split plots design, thethree regimes irrigation, S1= 95-100% available water(AW), S2= 75-80% AW and S3= 55-60 % AW were assigned to main plots and six bio-fertilizers, including T1= Rhizobium leguminosarum bv.  Strain of 177 and T2= Rhizobium leguminosarum bv.strain of 160 used for seed inoculation, T3= Arboscular mycorrizal (Funneliformis mosseaeand Rhizophagus irregularis) used for soil inoculation, T4= T1+T2, T5= T1+T2+T3 and T6= control were randomized to subplots. There were significant differences (p˂0.05) in yield and micronutrients concentration under irrigation regimes and bio fertilizers treatments. Highest grain yield (2371 kgha-1) was obtained in irrigation on 75-80 % available water and 160 Rhizobium inoculated treatment. The highest concentration of Fe, Mn, Zn and Cu in seed plant were in irrigation on 75-80% available water and co-inoculated treatment. The addition of Fe, Mn, Zn and Cu concentrations were, 21.4 %, 5.7%, 3.5% and 3.3% respectively than control treatment. These results suggest that inoculation of seed bean by Rhizobium and mycorrhiza, can improve yield and resistance to drought stress by increasing of micronutrients concentration in seed bean plant.

One of the main pillars of sustainable agriculture is the use of biofertilizers in agro-ecosystems to modify and reduce the use of chemical inputs. This study was carried out to investigate the effect of growth promoting bacteria on soil chemical properties in a clover- rice cropping system using a factorial experiment with randomized complete blocks having three replications at the research site of Rice Research Institute of Iran, during 2015- 17. Experimental factors for clover included four levels of inoculation with symbiotic bacteria Rhizobium trifolii and four levels of inoculation with non- symbiotic plant growth promoting bacteria. The results showed that clover cultivation led to a significant increase in the percentage of soil organic carbon (1.79%) and nitrogen (0.216%). The Application of non-symbiotic bacteria in clover cultivation caused a significant increase in soil phosphorus in rice cultivation. The highest amount of soil phosphorus was obtained in treatments of Pseudomonas (12.38%) and Azotobacter+ Pseudomonas (11.8 ppm) in rice cultivation. Also, rice cultivation significant reduced available potassium in the second year (121.1 mg/kg) compared to the first year (128.3 mg/kg). According to the overall results of this study, the use of growth promoting bacteria while maintaining and improving the chemical properties of the soil increased the average rice yield in the second year (3250.3 kg/ha).

In order to study the effects of rhizobium bacteria and arbuscular mycorrhizal fungi on water use efficiency and the grain yield of bean, under drought stress conditions, two-year year field experiments were conducted during 2015 and 2016 growing seasons. The experimental design was a split plot arranged in an RCBD with 4 replications. Three irrigations including S1= 95-100% AW (Normal irrigation), S2= 75-80% AW(Moderate drought stress) and S3= 55-60% AW (severe drought stress) were assigned to the main plots and six bio fertilizer treatments including T1=177 rhizobium bacteria strain, T2=160 rhizobium bacteria strain used for seed inoculation, T3= mycorrhizal arboscular fungi used for soil inoculation, T4= T1+T2, T5= T1+T2+T3 and T6= control (no seed and soil inoculation) were randomized to the subplots. Based on the combined analysis of variances for two years, there were significant differences (p˂0.05) in the grain yield, yield components and water use efficiency between the irrigation stress and bio fertilizer treatments. The highest grain yield (2371 kg ha-1) and water use efficiency (522 g m-3) were obtained in the S2T2 treatment. In this treatment, 160 and 177 rhizobium bacteria (T2) in moderate drought stress (S2) were used. These results suggested that inoculation with the rhizobium of seed bean in arid and semi-arid areas could improve yield, water use efficiency and resistance to drought stress by increasing the growth in the root and shoot of the plant.

Symbiotic bacteria associated with the root of legume plants were isolated from soil and the root nodules of alfalfa (Medicago sativaL.), chickpea (Cicer arietinum L.) and yellows alfalfa (Melilotus officinalis L.) grown in arsenic-contaminated areas in south eastern part of Kurdistan province, Iran. According to physiological and biochemical properties, isolates were identified as the members of Rhizobium and Ensifer genus. The presence of arsenic resistant system known as ars system was confirmed by amplification using primers corresponding to arsC gene. Growth rate of strains in different concentrations of arsenate was investigated in YEMB medium supplemented with 100-400 mM arsenate. Alfalfa,s isolates (AB1, AB3), chickpea,s isolates (PA2, PC2), yellow alfalfa,s isolate (YA1) and standard strain (Sinorhizobium meliloti SM117) were tolerant to 350 mM arsenate and (AB1, PA2 and YA1) isolates were moderately capable to grow at 400 mM arsenate. Among the identified strains, AB1 and PA2, were selected for greenhouse experiments. In order to evaluate the effect of arsenic contamination on legume-rhizobia symbiosis and biomass production of alfalfa and chickpea plants, an experiment was carried out based on a completely randomized design with a factorial arrangement in three replications. Experiment factors consisted of, three levels of rhizobia inoculation (with and without inoculation of AB1 and PA2) and five levels of arsenic concentrations (0. 10, 50, 75 and 100 mgkg-1 soil) under greenhouse conditions for 8 weeks. Results obtained in this study indicated that the fresh weight and dry weight of alfalfa and chickpea (shoot and root) were decreased as the arsenic concentration of the soil was increased. The results also showed that fresh and dry shoot and root weight of alfalfa and chickpea were significantly higher in rhizobia-inoculated treatments compared to non-inoculated plants.

The drought stress is the most important of abiotic stress for plants. In dryand regions, the implication of drought tolerant strains of rhizobia is a critical way to enhance yield and development of nitrogen fixation in beans farming.To investigate the effects of rhizobial strains on yield of common bean under drought stress, this study was performed based on randomized complete block design as a split plot experiment with 12 treatments in 3 replications during 2014 and 2015. The treatments were irrigated to achieve the values of 30, 60 and 80 % available soil moisture as drought stresses (sever-, moderate- and non-) in main plots and inoculated seeds by rhizobium bacteria strains 54, 58, 160 and 177 arranged in sub-plots. The volume of irrigation water, water use efficiency, plant nitrogen, yield and yield components were determined. The results in 2 years revealed that, the drought stress and rhizobium treatments showed significant (P-1) was obtained in irrigation level at 60 % available water (moderate stress) and seed inoculated by rhizobium bacteria strain 160. These results showed that, the application of rhizobium bacteria strain 160 increased drought tolerance without any reduction of yield in common bean.

This review attempts to reflect the history and importance of soil biology and the biological properties of soils in Iran. This paper also aims to extensively evaluate the biological characteristics of soil with respect to some features of soils, climate and vegetation. Then, the biological properties of the dominant soils in Iran are mentioned. Research findings about the possibility of using the soil biological potentials in agriculture, especially production and commercialization of technological knowledge of bio-fertilizers are discussed. Furthermore, the list and characteristics of useful soil microorganisms that exist in the country in a form of “Microbial Bank” are mentioned. Finally, the potentials and capacities of production and consumption of bio-fertilizers, the priorities and challenges encountered in the field of soil biology in the country are discussed.

This research investigate the potential of Rhizobium leguminosarum b.v. phaseoli to improve growth and nutritional status of common bean (Akhtar cultivar) at three levels of salinity of S0, S1 and S2 (0, 35 and 70 mM sodium chloride, or 0, 3 and 6 ds/m, respectively). The greenhouse experiment was conducted as a factorial design in randomized completely with three replications by using the sterile sand-perlite (2:1 v/v) as a culture substrate. The results showed that salinity decreased plant growth, regardless of microbial treatment and stress level. The inoculated plants with rhizobium had greater shoot and root biomass than the non-inoculated plants at all salinity levels. Salinity stress decreased enzyme activity catalase and potassium and nitrogen concentrations of shoot and increased enzyme activity peroxidase sodium concentration of shoot, particularly in non-inoculated plants with rhizobium. At salinity levels of S1 and S2, enzyme activity catalase of inoculated plants with rhizobium about 196% and 259% and enzyme activity peroxidase about 93%, 73% and 7% was increased than the non-inoculated plants, respectively. Inoculation of rhizobium at salinity levels of S1 and S2, resulted in increasing of potassium concentration about 84% and 10% and decreasing of sodium concentration about 50% and 70%, respectively. Also, the inoculated plants with rhizobium had higher nitrogen concentrations at S0 and S2 in compare to the non-inoculated. Shoot phosphorous concentration of inoculated plants with rhizobium was higher about 55% than the non-inoculated plants.

This study was conducted to evaluate N2-fixing ability of rhizobia strains inoculated with common bean. The experiment was carried out in a randomized complete block design (RCBD) with 13 treatments including 10 Rhizobium isolates، two nitrogen fertilizer levels (200 and 400 kg urea per ha) and one control (without Nitrogen and rhizobium) in four replications at Esmaeel Abad research station of Qazvin. Plant sampling was done in two growth stages and nodule number and dry weight، shoot dry weight and total N-uptake and seed yield were evaluated. Results of two years field experiment showed that isolate L-75 showed the superior N2-fixing performance and had the highest positive effect on growth factors and could be recommended to use as inoculants strain in Qazvin region. This isolate، produced highest nodule number and dry weight in both years of study. Seed yield production was promoted by 26 and 40% more than control by application of isolate L-75 in the first and second year، respectively. This study showed that inoculation of common bean with effective rhizobia strains resulted in promoting of plant growth and seed yield production and have the benefit to reduce nitrogen fertilizer application in bean cropping.

Using rhizobial inoculants in legumes cropping including chickpeas has attracted attentions because of economic advantages, decreasing chemical fertilizers utilization, and environmental health issues. Iran has 10 years of experience on production and utilization of these inoculants. For production of any rhizobial inoculant, it is vital to have a collection from effective and well-known strains of rhizobia. The aim of the current study was to characterize the isolates of chickpea rhizobia (collected by Soil and Water Research Institute from different parts of Iran) and to evaluate their genetic diversity. Bacterial isolates were purified on YMA plates and were subjected to microscopic, morphological, and plant infection analyses. Out of 120 isolates, 82 were able to nodulate the host plants and were considered as nod+ isolates. Identification of the isolates was carried out using biochemical test including utilization of carbohydrates, amino acids, and ability for growth in different cultural conditions. Results of the biochemical tests were used for clustering of isolates. Results showed that, the isolates could be divided into six groups, of which the majority belonged to M. ciceri. Six representatives were selected from each cluster and their 16 rRNA sequence was determined. Results of the study revealed that isolates C-22, C-35, C-35A, C-97 and C-105 belong to M. ciceri and the isolate SWRI-9 was M. mediterraneum.

The effects of heavy metals, as soil pollutants, on Rhizobia and symbiotic system of Rhizobium-legume are not clearly known. The aims of this study were to determine the effects of Cd on nitrogen fixation of native isolates of Sinorhizobium meliloti in Zanjan province soils. To isolate and obtain pure cultures of sinorhizobium meliloti isolates, root nodules were collected from different alfalfa farms contaminated by heavy metals, especially Cd, in Zanjan province. Plant infection tests were carried out on different strains to identify Rhizobia, then, isolates capable of nodulating were determined. Based on effectiveness of symbiosis and shoots dry weight of alfalfa in greenhouse condition, nitrogen fixation efficiency of different isolates was examined and compared with each other. The results showed that different isolates had different nitrogen fixation efficiencies and the isolates were classified into four groups, namely, very effective, effective, partially effective, and not effective. In the second part of the experiment, resistance of different sinorhizobium meliloti isolates to Cd was examined using selective medium of HEPES-MES containing different amounts of Cd. The highest concentration of heavy metals supporting growth for each isolates was determined as the maximum resistance level (MRL) and, based on it, the isolates were classified into three groups, namely, sensitive, relatively sensitive, and tolerant. In the final experiment, the effective isolates (capable of nodulating) with low and high tolerance to heavy metals were selected and used for a pot experiment. In this experiment, the effects of five sinorhizobium meliloti isolates (S6, S12, S17, S41 and S51) as inoculants, and five concentrations of heavy metals were examined on growth of alfalfa plant in a mixture of perlite and sand as media. A control and a treatment receiving 70 mg/kg N were also included in this experiment. The highest and lowest biomass yields of alfalfa were obtained for control and those treatments inoculated with resistant isolates to Cd. The S51 isolates was tolerant to Cd and had higher nitrogen fixation ability than the other isolates. The S17 and S3 were the most tolerant and the most sensitive isolates to Cd, respectively.

In this research 220 rhizobial bacteria were isolated from two lentil dryland farming flat plains of Moghan and Koohin. They were then tested in vivo as well as in vitro to make assurance of 184 purified strains of rhizobium leguminosarum biovar vicial (lentil). BTB +YMA culture media with different levels of salinity through NaCl (10, 20,30,40,50dS/m) application were used in salinity tolerance test of lentil rhizobial symbiosis strains. Among the 189 rhizobial strains, 101 were found out to be completely sensitive (EC=10 dS/m), 25 were very tolerant while 10 were classified as super strains, because of their being completely tolerant to salinity. The numbers of Koohin flat plain nurtured rhizobial strains in five salinity levels (in the range of 10 to 50) were respectively 55, 51, 50, 27, 37 while for Moghan flat plain, these numbers were recorded 46,42, 21, 8 and 8, Altogether Koohin flat plain rhizobacteria were more highly salinity tolerant than Moghan flat plain rhizobacteria. Drought tolerance test of rhizobial strains was performed in PEG 6000 +YMA culture media. The drought levels were evaluated as based on optical density of bacterial suspensions prepared for the test. Drought tolerance of rhizobacteria were grouped in 4 levels of completely tolerant, tolerant, sensitive and completely sensitive by as judged through respective optical densities of OD<0.3, OD=0.3-0.4 OD=0.4-0.5, OD>0.5. From among the 10 super strains(completely tolerant) identified, 6 from Moghan flat plain, and 2 super strains from Koohin flat plain were selected. At last it is hoped that the super strains (salinity and drought) identified in this phase of research can be effectively used in later greenhouse studies.

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.

Many plant growth promoting rhizobacteria (PGPR) contain 1-aminocyclopropane-1-carboxylate (ACC) deaminase enzyme that can convert the ACC, the immediate precursor of ethylene in plants, to ammonia and? -ketobutyrate and cause a decrease in stress emanted ethylene. Wheat is a strategic crop and the people’s main staple in Iran. On the other hand salinity stress prevails in many soils as well as in many water resources in Iran. Therefore it is essential to find and offer the operational measures for increasing wheat yield in these conditions. In this greenhouse research work, the effect of two strains of Sinorhizobium meliloti namely KYA40 and KYA71 that contain ACC deaminase enzyme and S. meliloti KYA95 (non ACC deaminase enzyme containing, as control) on growth and on nutrients uptake of wheat in salinities of 7 and 10 dS.m-1 and SAR=10 mmol.l-1 in a complete factorial randomized block design was investigated. The results indicated that inoculation with strain KYA40 significantly increased the shoot length, shoot weight, root length, as well as Fe,Mn and Cu uptake. This strain increased shoot and root lengths by 13% and 34% respectively in 7 ds.m-1. Strain KYA40 increased the shoot dry weight by 9% in 10 dS.m-1 compared to non-inoculated. This strain increased Fe, Cu and Mn uptake by 47,45 and 37% (in 10 dS.m-1) respectively. Inoculation was not observed to have any significant effect on length and weight of ears, leaf area index, flag leaf lengh, flag leaf area, N, P, K and Zn uptake

To investigate drought tolerant isolates of rhizobial symbioant of lentil (Lens culinaris L.), 12 soil samples were collected from cultivated and non-cultivated area of Golestan, Chaharmahal-O-Bakhtiari and Isfahan provinces. Local cultivars of lentil including Binam Dorosht, Ghazvini and Faridani were planted in each soil sample. After 10 weeks, a total of 324 rhizobial isolates were recovered from root nodules of the lentil plants. Evaluation of the ability of the isolates to grow at different concentration of salt showed that all isolates grew normally on 200 mM NaCl and only 20% was determined as salt tolerant isolats(>400mM). Among the isolates RL249 was classified as superior salt tolerant strain due to growing on 600 mM salt. The drought tolerance of the isolates was also examined, using PEG6000. In general, the salt tolerant isolates were also drought tolerant, however their tolerance to salinity and drought is not related to their geographical origin. In a randomized split factorial design with three replications, the effectiveness of tolerant isolates(RL249 and RL211) and a sensitive strain (RL 77) was compared on two cultivars of lentil (Binam Dorosht and Faridani) under water stress treatments with the consumptions of 50, 75,90 and 98% of soil available water. Although nodulation rate was reduced in both cultivars as the consequence of drought stresses, plants of Binam Dorosht cultivar showed high nodulation rate due to the increased fresh weight of the roots. Despite the fact that RL249 was identified as a superior nodulating and salt/drought isolate, however nodulation efficiency was decreased significantly under water stress treatments with more than 50 % of soil available water.