mr sarikhani

In this study, three domestic biofertilizer samples including Azotobarvar, Potabarvar, Ruein, and a sample of Indian biofertilizer called Phosco were studied in terms of microbial population count and plant growth promoting characteristics. The results of plate counting revealed that Potabarvar had no alive bacterial population, but the number of viable cells of Azotobarvar, Ruein and Phosco were 3.5 × 108, 5.2 × 108 and 6.9 × 103 CFU g-1, respectively. Moreover, two isolates (Az1 and Az2), three isolates (R1, R2 and R3) and three isolates (P1, P2 and P3) were isolated in Azotobarvar, Ruein and Phosco, respectively. The in-vitro results of plant growth promoting characteristics showed that in the solid LG medium R1 and Az2 and in the liquid LG medium, P1, R1 and Az2 and had the highest nitrogen fixation, respectively. In phosphate solubilizing from tricalcium phosphate, Az1 and Az2, in potassium releasing ability, Az1 and P1 isolates from biotite and Az1 and P2 from muscovite and in production of auxin P1 in the presence of tryptophan had the highest performance, respectively. The isolates P1, P3, R1 and R3 had antifungal activity against Fusarium solani. Summarizing the results of microbial population counts as well as plant growth promoting characteristics showed that the both Ruein and Azotobarvar biofertilizers were in desirable condition and Phosco biofertilizer, despite having some growth-promoting properties, lacked a sufficient microbial population and the Potabarvar biofertilizer lacked the microbial population.

Bacteria with high phosphate solubility and resistance to high temperature are suitable candidates for use in granular phosphatic microbial fertilizers (PMF). The prepared product in processing of these fertilizers (PMF) is exposed to high temperatures (50-55 ° C) under very low moisture conditions. Accordingly, in this research, the efficiency of phosphate dissolution and temperature tolerance of 150 bacterial isolates were evaluated. These bacteria were prepared in the soil biology laboratory of University of Tabriz. The phosphate solubility of these bacteria was evaluated by semi-quantitative and quantitative methods in solid and liquid Sperber medium in the presence of low-soluble tricalcium phosphate (TCP) source at the temperatures of 28 °C and 55 °C. The results showed that there was a significant difference between bacteria in terms of dissolution of phosphate. At a typical temperature among 150 bacteria, 25 bacteria (17%) had no phosphorus dissolution capacity, and the HD/CD ratio for these 25 bacteria was 1.2 to 2.8. In the quantitative method, the solubility potential of 25 isolates was 175.88- 292.98 mg P/l. Among the 25 isolates, only 7 bacteria were able to survive at 55 ° C for 16 hours, witch between them the C1-4O, C19-4O and C8-12M bacteria had the highest halo diameters with values of 2.5, 2.4 and 2.2 for the HD/CD ratio, respectively. The amounts of phosphorus release by these bacteria in the liquid medium were 244.08, 256.44 and 216.14 mg/l, respectively. The molecular identification of these bacteria showed that they were belonged to the genus Enterobacter and Stenotrophomonas.

Bacteria with high phosphate solubilization ability and resistant to high temperatures are good candidates for using in phosphatic microbial fertilizers (PMF). Accordingly, in this study the dissolution of phosphate, thermal tolerance and viability of seven PSB (Pantoea agglomerans P5, Pseudomonas fluorescens Tabriz, P. putida Tabriz, Pseudomonas sp. C16-2O, Enterobacter sp. S16-3, Bacillus megaterium JK6 and B. firmus) were evaluated in the basal formulation of rock phosphate (45 g), bagasse (30 g) and sulfur (15 g) after providing appropriate initial microbial population. The prepared PMFs was divided into two parts and the number of viable cells was obtained after three and six months by plate count method. The provided PMFs were subjected to microbial counts in two ways. A) Half of fertilizer samples, were stored at room temperature then viable cells counted and B) The other half of PMF were counted after they had been exposed to a temperature of 55 °C for 16 hours. The results showed that there was a significant difference between different phosphorus sources in terms of phosphate dissolution, and dissolution of bacteria from TCP sources compared to rock phosphate was two-fold. The highest and lowest dissolution of phosphate observed in the bacterium P. agglomerans (562 mg/l) and B. firmus (395 mg/l), respectively. None of the bacteria in PMFs formulations did not tolerate at temperatures up to 55°C, but PMFs that stored at room temperature, after three and six months of production, had an average population of 4.3 × 105, and 0.4 × 104 CFU/g, respectively.

There are different methods for evaluation of the biological nitrogen fixation, which they are mainly included acetylene reduction assay, labeled nitrogen and nitrogen difference methods. Accuracy and sensitivity of these methods are different, but applying of some of these methods isn’t possible in all laboratories, so it cause the use of less accurate methods for evaluation of the nitrogen fixing content. Therefore, this article was aimed to investigate the content of nitrogen fixation (NF) of some bacteria isolates including Azotobacter using the Kjeldahl method. A total of 22 bacteria isolates were used and evaluated. The isolates were cultured in solid and liquid LG media and the content of the nitrogen fixation was measured in solid and pellet of liquid culture. According to the results of digestion, distillation and titration (Kjeldahl) of the cultured sample in the solid medium, the maximum nitrogen-fixation content 261.10 and 258.64 µg/g were found in 14SP- Ш and 14SP2-1, respectively. The highest nitrogen-fixation content in liquid culture medium was obtained in 14SP-I (80 µg/ml). The results of liquid and solid culture media indicated that the maximum nitrogen in14SP-I and 14SP2-1 isolates belonged to the Azotobacter chroococcum, Pseudomonas 35SP-2, and Achromobacter 14SP- Ш. The results of NF in both solid and liquid cultures showed a good correlation (r=0.69**). It seems that the method can be used for screening the efficient nitrogen fixing bacteria, although this is not so a precise method. 14SP-Ι, 14SP-Ш, 14SP2-1, 35SP-2 and 44SP-2 strains can be suggested among the isolates for the greenhouse and farm experiments.

Attention to the potassium releasing bacteria is due to high demand of plants to this element. Therefore, in this study the effects of 15 bacterial isolates (S5-5, S5-9, S6-6, 10-3, S11-2, S12 -3, S14-1, S14-3, S15-1, S16-3, S17-4, S19-1, S19-2, S20-7 and S21-1) and Pseudomonas putida strain P13 on the growth and potassium nutrition of tomato were assessed. The experiment was performed under sterile condition in a bed of sand and Muscovite and other nutrients, except potassium, during the growing season were supplied through Hoagland solution. The results showed that the application of the 16 isolates didnt affect the wet and dry weight of shoot and the concentration and content of root potassium but the plant height, wet and dry weight of root, total dry weight of plant, concentration and content of shoot potassium and the concentration and content of root phosphorus significantly increased in some isolates in comparison to the un-inoculated treatment. The highest height of the plant with an increase of 16.56% compared to the uninoculated control was observed in the isolate S21-1 (48.08 cm). The highest total dry weight of plant was measured with the strain S19-1 (6.35 g pot-1) and maximum concentration of potassium in shoot (14.3 mg g-1) was observed in the isolate S10-3. The most content of the shoot potassium (78.67 mg pot-1) gained in isolate S10-3 which in comparison with the non-bacterial control showed an increase of 70 %. Molecular and biochemical identification results (16S rDNA) showed that efficient isolates belonged to the genus Pseudomonas.

Identifying of plant growth promoting bacteria and utilizing them is one of the basic stages in sustainable agriculture. In this experiment some newely isolated and identified strains of Pseudomonads, were used for the first time in inoculation of tomato in the field circumstances. Experiment was done based on randomized block design with 5 treatments and 3 replications. In this experiment tomato (Lycopersicon esculentum Mill cv. Super Chief) seedlings were inoculated with integrated treatment of Pseudomonas ssp. strains including (S19-1䭝3, S14-3䭟1 and S19-1䭭1), moreover, the control treatment without bacteria inoculation and fertilizer treatment (according to soil test) inorder to copmparison were considered. The result showed that the effects of bacteria on characters such as yeild, fruit size, vitamin C, lycopen, percentage of N, P, K in foliage of plant and leaf area index is meaningful and the best output is in S19-1䭞3 (4830.9 g.m-2) and the highest amount of vitamin C, lycopene, N, P, K, LAI was in S191-1䭭1 treatment respectively and amounts of 7.02 mg.100g-1 Fwt, 46.01mg.kg-1, 30.09 mg.g-1, 7.30 mg.g-1, 15.60 mg.g-1, 6.60 cm2. However the other measured traits in this experiment including number of fruits, acidity, TSS, pH, EC, firmness, diameter of stem, number of lateral shoot and chlorophyll index were not affectd by bacteria. According to this result we can mention the efficiency of used bacteria as a biofertilizer in improvement of yeild, nutrient uptake, LAI and fruit quality.

The benefits of biofertilizers in agriculture depend on the use of effective strains with desirable motivating plant growth characteristics. The quality control of the biofertilizers, especially in terms of investigating and proving the genus and species of the bacteria used in them is one of the most important criteria. Therefore, in this study, isolates of the four types of common nitrogen and phosphate biofertilizers in Iran, including Barvar2 (Ba1 and Ba2), Biosuperphosphate (Bio1, Bio2, Bio3 and Bio4), Supernitroplus (Sn1 and Sn2) and Nitroxin (N1, N2, N3, N4 and N5) were studied for the correctness at the genus and species levels. The molecular identification method was applied based on amplifying the 16S rDNA genes using universal primers 27F and 1492R. Also, the bacterial genus and species used in the biofertilizers were determined by proper biochemical tests. The results showed that the isolates N1, N5, Sn2 and Bio3 had a similar phenotype and all of them belonged to the Pseudomonas genus. Also, the Sn1 and Bio4 isolates had morphological and molecular similarities belonging to the Bacillus genus. The results of identification for the isolates Ba1, Ba2, Bio2, N2, N3 and N4 showed that they were Pantoea, Pseudomonas, Acinetobacter, Pseudomonas, Citrobacter and Pseudomonas, respectively. Among the isolates, the presence of Citrobacter (N3) and Acinetobacter (Bio2) in the Nitroxin and Biosuperphosphate biofertilizers were noticeable, because they had not been reported by manufacturers in ingredient of the mentioned biofertilizers. However, contrary to the Nitroxin and Supernitroplus biofertilizers manufacturers’ claim about using two isolates Azotobacter and Azospirillum, the present study indicated the lack of these bacteria in these biofertilizers.

Arbuscular mycorrhizal (AM) fungi are beneficial not only for providing plants with nutrients but also for improving the soil structure and aggregate stability by producing glomalin، which is a glycoprotein. A completely randomized block experimental design was conducted with two species of arbuscular mycorrhizal fungi، Glomus intraradices (GI)، Glomus etunicatum (GE) and non-mycorrhizal (control) under growth of tomato with four replicates in a sandy loam soil at greenhouse conditions. Results showed that GI and GE significantly (P < 0. 01) increased mean weight diameter of aggregates (MWD) by 193. 4 and 288. 8 %، mesopores by 49. 7 and 25. 9 %، micropores by 5. 5 and 19. 6 %، field capacity (FC) moisture by 14. 1 and 35. 1 %، permanent wilting point (PWP) by 12. 4 and 22. 6 %، available water capacity (AWC) by 14. 9 and 41. 3 %، but decreased bulk density (Db) by 4. 1 and 8 %، macropores by 10 and 14. 1 %، saturated hydraulic conductivity (Ks) by 52. 4 and 70. 8 %، respectively in comparison with control treatment. GI and GE fungi significantly (P < 0. 01) increased uptake of phosphorus and potassium by 600. 8 and 1089. 2 %، 506. 2 and 811. 5 %، respectively relative to the control in tomato shoot.

Oil contamination in Iran due to high application of oil compounds, is one of the most dangerous pollution factors. Bioremediation is a prime strategy for remediation, by which the pollutants can be removed by making use of microorganism or any biological process that employes microorganisms or their enzymes to rehabilitate the environment altered by the contaminants. With regards to the importance of this method, screening and isolation of oil-degrading bacteria from contaminated site of Bushehr province were done in Carbon Free Minimal Medium enriched by gas oil. In this study 19 isolates of bacteria (PDB 1-19) were isolated, and the molecular and kit identifications showed different genus and species such as Stenotrophomonas maltophilia, Ralstonia sp., Vibrio sp., Sphingobacterium sp., Zymomonas sp., Pseudomonas aeruginosa, Paracoccus sp., Pantoea sp., Achromobacter xylosoxidans, Acinetobacter johnsonii, Serattia odorifera, Pseudomonas alcaligenes, Entrobacter cloacae, Pseudomonas stutzeri and Chryseobacterium sp.. In order to determine the efficiency of these bacteria in hydrocarbondegradation an inoculum of pure culture of bacteria containing 108 cfu/ml was used in liquid assay, which was performed in factorial experiment based on completely randomized design with 2 replications. Utilization of hydrocarbon sources was again detected in CFMM broth supplemented with 2% gas oil where the growth turbidity (OD600nm) as an indicator for utilization of hydrocarbon and bacterial growth was measured at different times of 0, 48, 168, 216 and 312hr. Results showed that in CFMM broth assay all main factors including bacteria and time as well as their interaction were significant (p<0.01). These bacteria were effectively able to mineralize gas oil and among bacteria, best results was achieved by Chryseobacterium sp.. The ability of bacterial isolates for degradation of oil-compounds increased by increasing time of incubation.

Soil and water contamination by oil is one of the great environmental concerns. Bioremediation is one of principal strategies for remediation، wherein the pollutants can be removed by use of microorganism or any biological process that uses native or exogenous microorganisms. According to the positive role of Pseudomonas genus in bioremediation، in this study the potential of two Pseudomonad bacteria، including Peudomonas fluorescens CHAO، P. putida P13 and a non-Pseudomonad Pantoea agglomerans as hydrocarbon utilizing bacteria were estimated in presence of three compounds including gas oil (2%)، toluene (1%) and phenanthrene (0. 05%). Bacterial inoculum containing 108 cfu/ml was used in plate and liquid assays، which were performed in factorial experiment based on completely randomized design with three replications. Results showed that in CFMM plate assay، diameter of colony is not affected by any of bacterial isolates and compounds. In broth assay، P. putida P13 and P. fluorescence CHAO had similar behavior in the presence of Gas oil، toluene and phenanthrene and trend of bacterial growth was the same at different times، while with P. agglomerans P5 the lowest number of bacteria was achieved. Among three compounds the highest degradability was recorded to the gas oil، followed by phenanthrene and toluene. The ability of bacteria in degradation of oil-compounds increased by increasing time of incubation. To conclude، this study suggests the potential use of two Pseudomonas isolates for bioremediation of hydrocarbon-contaminated environments especially with aliphatic hydrocarbon.