S. Nikmehr; A. Akhgar
Abstract
Introduction: Phosphorus (P) is considered to be one of the most essential macro elements required for growth and development of plants, but, due to low solubility and fixation in soils, only a small fraction of phosphorus in soil (1 ppm or 0.1%) is readily available to plants. chemical fertilizers are ...
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Introduction: Phosphorus (P) is considered to be one of the most essential macro elements required for growth and development of plants, but, due to low solubility and fixation in soils, only a small fraction of phosphorus in soil (1 ppm or 0.1%) is readily available to plants. chemical fertilizers are widely used in meeting the phosphorous need of crops. However, as the fertilizer production is dependent upon fossil energy sources, continuous use of chemical fertilizers has become a matter of great concern, not only because of the diminishing availability of costly inputs but environmental concerns also. Under this background, it has obviously brought the subject of mineral phosphate solubilization in the forefront. A group of soil microorganisms is recognized to be involved in microbial phosphate solubilization mechanisms through which insoluble forms of inorganic and organic phosphates convert into soluble forms (HPO4-2 or H2PO4-). Acidification of the medium, chelating, exchange reactions and production of various acids has been discussed as the key processes attributed to the conversion. Phosphate solubilizing bacteria (PSB) are a group of plant growth promoting rhizobacteria (PGPR) that convert unavailable forms of phosphorus to available forms and it helps to the growth and yield of plant. The use of plant growth promoting rhizobacteria (PGPR) is considered one of the most important factors increasing sesame yields. Therefore, the aim of the present study was to investigate the interactive effects of PGPR and phosphorus fertilizer on some growth parameters and components of yield and also phosphorus and Zinc uptake in sesame.
Materials and Methods: In order to investigation of the effect of combined application of phosphate solubilizing bacteria and phosphorus fertilizer on growth and yield of Sesame, a greenhouse experiment was conducted as factorial based on completely randomized design with three replications including five levels of phosphorous fertilizer (0, 100, 200 and 400 kg ha-1 of triple superphosphate and 1200 kg ha-1 of rock phosphate) and three bacterial levels (inoculation with two phosphate solubilizing fluorescent pseudomonad, isolates of P3 and P5 that known in this study as B1 and B2 and non-inoculated). It should be noted that rock phosphate used in this study has contained 4% of zinc oxide. The bacteria selected from microbial bank of Vali-E-Asr University were able to dissolve the insoluble phosphate and produce siderophore and IAA. Four months after planting, plants were cut at the soil surface, and shoot dry weight, stem height, number of Seeds in pot, seed dry weight and seed oil percentage were recorded. Also phosphorus and Zinc contents in shoot were determined.
Results and Discussion: Results indicated that both bacteria (B1 and B2) significantly increased shoot dry weight and B1 increased seed dry weight. Also application of phosphorus fertilizer significantly increased shoot dry weight and plant height. 200 kg ha-1 of triple superphosphate had highest shoot dry weight and was similar with rock phosphate. Combined application of Phosphorous fertilizer and phosphate solubilizing bacteria increased shoot dry weight. Results also showed that seed oil was increased by application of Phosphate rock. Phosphorus concentration in seed was increased with Using B1 and B2 isolates. Application of B2 significantly increased phosphorus concentration in seed (11.5%) and Phosphorous fertilizer levels increased concentration of P and Zn in seed. Application of 200 and 400 kg ha-1 triple superphosphate had the highest concentration of P and Zn in seed. Phosphorus fertilizer levels significantly enhanced uptake of P and Zn in shoot. Application of 200 and 400 kg ha-1 triple superphosphate led to increased uptake of phosphorous in shoot. Also rock phosphate significantly increased uptake of Zn in shoot. Combined application of Rock phosphate and bacteria of B1 and B2 had more significant effects on uptake of Zn in shoot.
Conclusion: this study showed that Phosphate solubilizing bacteria (B1 and B2) had significant effects on the growth and nutrient uptake especially phosphorus and zinc in sesame. The simultaneous application of Phosphate rock and Phosphate solubilizing bacteria increased most of the measured parameters similar to the highest levels of triple superphosphate. Therefore, because of high cost of chemical fertilizers production and its environmental problems, application of less levels of phosphorus fertilizers or rock phosphate along with Phosphate solubilizing bacteria could be an appropriate option to avoid wasteful consumption of phosphorus fertilizers.
T. Poorbafrani; A. Tajabadi Pour; V. Mozafari; A.R. Akhgar
Abstract
Introduction: Pistachio is one of the most important crops in many regions of Iran with respect of production and export. There are more than 470000 ha of nonbearing and bearing pistachio trees mainly in Kerman province. Despite the economic importance of this crop, very little information is available ...
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Introduction: Pistachio is one of the most important crops in many regions of Iran with respect of production and export. There are more than 470000 ha of nonbearing and bearing pistachio trees mainly in Kerman province. Despite the economic importance of this crop, very little information is available on its nutritional requirements. Pistachio trees like other crops need to macro and micro nutrients. one of these elements is manganese (Mn). Manganese is an essential mineral nutrient, playing a key role in several physiological processes, particularly photosynthesis, respiration and nitrogen assimilation. This element is normally supplied to the plants by soil. Therefore, soil conditions affect its availability to plants. Soils with high pH, calcareous soils, especially those with poor drainage and high organic matter, are among the soils which produce Mn-deficient plants. Calcium carbonate is the major inactivation factor of Mn in calcareous soils. The soils of Iran are predominantly calcareous in which micronutrients deficiency, including Mn, is observed due to the high pH and nutrient fixation. The objective of this research was to examine the effect of manganese application on growth and chemical composition of pistachio seedlings in some calcareous soils with different chemical and physical properties.
Materials and Methods: For this purpose a greenhouse experiment was carried out as factorial (two factors including soil type and Mn levels) experiment in completely randomized design with three replications. Treatments were consisted of three levels of Mn (0, 10 and 20 mg Mn Kg-1 soil as Manganese sulfate) and 12 different soils from Rafsanjan region in Southern Iran. Soil samples were air dried and crushed to pass through a 2-mm sieve, and some physical and chemical properties of soils such as texture, electrical conductivity, pH, organic matter content, calcium carbonate equivalent, cation exchange capacity and iron, manganese, copper and zinc availability were determined. Then plastic pots were filled with 5 kg of these soils. Pistachio seeds (cv Badami Zarand) were placed in muslin sacks and pretreated for 24 h with Benomyl solution. The germinated seeds were planted in each pot, and each pot was irrigated with distilled water. Nitrogen and phosphorous were applied uniformly to all pots at the rate of 50 mg kg−1 soil as ammonium nitrate and potassium dihydrogen phosphate forms, respectively. Zinc, iron and copper also were added to treatments at level of 5 mg kg−1 soil as zinc sulfate, iron sequestrine138 and copper sulfate. After 24 weeks, the seedlings were cut at the soil surface, and the roots were washed free of soil. Leaves, stems and roots were dried at 70 oC for 48 h in an oven. The total leaf, stem, and root dry weights were recorded. The ground plant samples were dry- ashed at 550oC, dissolved in 2 N HCl, and made to volume with hot distilled water. Plant Mn, Cu, Zn and Fe concentrations determined by atomic absorption spectrophotometry. All data were statistically analyzed according to the technique of analysis variance (ANOVA) by MSTATC.
Results and Discussion: Results indicated that the application of manganese increased leaf, stem and root dry weight of pistachio seedlings so that the maximum amount of the dry weight of roots stems and leaves of pistachio seedlings were observed at 10 mg Mn kg-1soil. Application of 10 mg Mn kg-1 soil increased leaf, stem and root dry weight by 19.2%, 25.2% and 23.9% in comparison to control, respectively. Chemical composition (concentration and uptake) of shoot of pistachio seedlings was also affected by Mn application. Mn application decreased the concentration and uptake of iron, concentrations of copper and zinc in Pistachio seedling shoots so that the highest concentrations of these elements were observed in control treatment. Reductions in concentrations of zinc and copper elements in 10 mg Mn kg-1 treatment were not statistically significant but in 20 mg Mn kg-1 treatment they were significant.
Conclusions: The results of this research showed that the application of 10 mg Mn kg-1soilto highly calcareous soils significantly increased most of growth parameters of pistachio seedlings in comparison to control. Although higher amounts of manganese (20 mg Mn kg-1 soil) reduced the growth parameters than the previous level. In overall, the results of this study indicated that for optimum growth and chemical composition of pistachio seedlings in calcareous soils, application of 10 mg Mn kg-1 sol is necessary.
A. Akhgar; K. Khavazi; N. Khakipoor
Abstract
Abstract
The aim of the present research was to isolate plant growth promoting rhizobacteria producing ACC deaminase which was able to alleviate negative effects of salinity on plant growth. 21 composite soil samples and Canola roots were collected from the saline and relatively saline soils of Qom ...
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Abstract
The aim of the present research was to isolate plant growth promoting rhizobacteria producing ACC deaminase which was able to alleviate negative effects of salinity on plant growth. 21 composite soil samples and Canola roots were collected from the saline and relatively saline soils of Qom and Qazvin provinces. 105 strains were selected from the soil rhizosphere of Canola. According to the growing abilities of the strains in the minimum media of DF having ACC, as the only source of nitrogen, it was determined that 14 strains had the ability to produce ACC deaminase. Identification of strain was carried out according to Bergey’s manual criteria. Results indicated that all the strains belonged to the group of fluorescent Pseudomonads. According to the tests, related to strain determination, 14 strains were identified as P. fluorescent. Measuring ACC deaminase activity showed that the activity of this enzyme in the isolated strains differed from 1.43 to 8.17 μmol α-ketobutyrate/mg/hr. Also the isolates produced IAA in TSB medium between 0.8 – 2.17 μmol/ml. In the present study, effect of selected strains on reducing negative effects of salinity on Canola seedlings growth was evaluated under greenhouse conditions. Under salinity stress, all ACC deaminase producing strains were able to increased canola growth parameters containing shoot fresh and dry weight, shoot and root length. Among tested strains, P12 was the most effective. There was a high correlation between root length and dry matter, and the activity of ACC deaminase producing bacteria. Also with increase salinity from 6 to 8 dS/m, shoot fresh weight and stem length were significantly decreased.
Keyword: ACC deaminas, Pseudomonas, Canola, Salinity
ahad faalian; M. Abolhasani Zeraatkar; A. Lakziyan; A. Akhgar
Abstract
Abstract
Incorporation of plant residues in soils is an important agricultural practice for maintaining soil fertility under organic management systems. Plant residues quality, soil physical and chemical properties, and the microbial population diversity of soils are the most important factors influencing ...
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Abstract
Incorporation of plant residues in soils is an important agricultural practice for maintaining soil fertility under organic management systems. Plant residues quality, soil physical and chemical properties, and the microbial population diversity of soils are the most important factors influencing the decomposition of added organic matter to soils. Decomposition rate of municipal wastes compost, vermi compost, manure and pistaco compost was studied in two soil samples with contrasting texture, two herbicides and three salt concentrations under laboratory condition. Soil moisture was adjusted at 50% water holding capacity and soil samples were incubated at 28 oC. The CO2 production was used as an index for decomposition rate of organic matter. Result showed that decomposition rate of pistaco compost is higher than those municipal wastes compost of vermi compost and manure. The CO2 evolution concentration and the rate of organic matter decomposition followed , and equations, respectively. A positive correlation was found between the rate of organic matter decomposition and K value. The results also showed that high decomposition rate based on K value, belong to pistaco compost, manure, municipal wastes compost and vermi compost, respectively.
Keywords: Organic matter, Decomposition rate, Soil texture, Soil salinity, Pistaco compost
M. Abolhasani Zeraatkar; A. Lakziyan; A. Jafari Gholamhossien pour; A. Akhgar
Abstract
Abstract
Osmoreguolation is a physiological processes that plant cell uses to maintain water balance and it is generally caused by metabolite accumulation inside the cell. Inoculated legumes by some drought tolerant Sinorhizobium isolates helps osmoreguolation by increasing biological nitrogen fixation. ...
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Abstract
Osmoreguolation is a physiological processes that plant cell uses to maintain water balance and it is generally caused by metabolite accumulation inside the cell. Inoculated legumes by some drought tolerant Sinorhizobium isolates helps osmoreguolation by increasing biological nitrogen fixation. In order to find some drought tolerant sinorhizobium isolates, 80 isolates were isolated and purified from different parts of Kerman province. They were tested for drought tolerant in liquid Trypton Yeast medium with different water potential (0, -1, -2 and -3.5 MPa using PEG 6000) and then they were classified into tolerant and sensitive groups. Four out of eighty isolates of Sinorhizobium (two from each group) were selected for a greenhouse experiment. The experiment was carried out in a factorial arrangement with a completely randomized design. The results showed that in water stress condition, inoculated plant substantially increased the nitrogenase activity, shoot dry weight, proline content, root soluble sugars, soluble protein concentration, K/Na in shoot and root by 2, 3, 2.7, 1.7, 1.1, 3 and 2 times, respectively.
Keywords: Sinorhizobium, Alfalfa, Water stress, Nitrogenase activity, Reducing sugars, Proline
A.R. Akhgar; K. Khavazi
Abstract
Abstract
In this study a greenhouse experiment was conducted to evaluate the role of ACC deaminase enzyme on alleviation of salinity stress of canola plant. Canola plants were exposed to Pseudomonas fluorescens strain P12 which contains a rhizobacter capable of producing Pseudomonas fluorescens in comparison ...
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Abstract
In this study a greenhouse experiment was conducted to evaluate the role of ACC deaminase enzyme on alleviation of salinity stress of canola plant. Canola plants were exposed to Pseudomonas fluorescens strain P12 which contains a rhizobacter capable of producing Pseudomonas fluorescens in comparison with plants exposed to mutant Pm12 unable to produce the required enzyme. The mutant was chemically produced using Ethyl Methane Sulfonate (EMS). Comparison of wild strain P12 with its mutant Pm12 indicated that under both saline and non-saline conditions, strain P12 significantly enhanced canola growth parameters including shoot fresh and dry weight, root dry weight, shoot length and green area index. In addition, canola plants inoculated with strain P12 absorbed higher rates of sodium, potassium, calcium, and magnesium, which can be attributed to enhanced roots growth. However, comparing strains P12 with Pm12 indicated that the production of ACC deaminase enzyme by P12 enhanced canola salinity tolerance and consequently, its growth.
Keywords: ACC deaminase, Pseudomonas sp., Salinity, Canola
