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J M Barea - One of the best experts on this subject based on the ideXlab platform.
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the application of isotopic 32p and 15n dilution techniques to evaluate the interactive effect of phosphate Solubilizing rhizobacteria mycorrhizal fungi and rhizobium to improve the agronomic efficiency of rock phosphate for legume crops
Nutrient Cycling in Agroecosystems, 2002Co-Authors: J M Barea, M Toro, M O Orozco, E Campos, R AzconAbstract:A pot experiment was designed to evaluate the interactive effects of multifunctional microbial inoculation treatments and rock phosphate (RP) application on N and P uptake by alfalfa through the use of 15N and 32P isotopic dilution approaches. The microbial inocula consisted of a wild type (WT) Rhizobium meliloti strain, the arbuscular mycorrhizal (AM) fungus Glomus mosseae (Nicol. and Gerd.) Gerd. and Trappe, and a phosphate Solubilizing rhizobacterium (Enterobacter sp.). Inoculated microorganisms were established in the root tissues and/or in the rhizosphere soil of alfalfa plants (Medicago sativa L.). Improvements in N and P accumulation in alfalfa corroborate beneficial effects of Rhizobium and AM interactions. Inoculation with selected rhizobacteria improved the AM effect on N or P accumulation in both the RP-added soil and in the non RP-amended controls. Measurements of the 15N/14N ratio in plant shoots indicate an enhancement of the N2 fixation rates in Rhizobium-inoculated AM-plants, over that achieved by Rhizobium in non-mycorrhizal plants. Whether or not RP was added, AM-inoculated plants showed a lower specific activity (32P/31P) than did their comparable non-mycorrhizal controls, suggesting that the plant was using otherwise unavailable P sources. The phosphate-Solubilizing, AM-associated, microbiota could in fact release phosphate ions, either from the added RP or from the indigenous ``less-available'' soil phosphate. A low Ca concentrations in the test soil may have benefited P solubilization. Under field conditions, the inoculation with AM fungi significantly increased plant biomass and N and P accumulation in plant tissues. Phosphate-Solubilizing rhizobacteria improved mycorrhizal responses in soil dually receiving RP and organic matter amendments. Organic matter addition favoured RP solubilization. This, together with a tailored microbial inoculation, increased the agronomic efficiency of RP in the test soil that was Ca deficient at neutral pH.
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the use of isotopic dilution techniques to evaluate the interactive effects of rhizobium genotype mycorrhizal fungi phosphate Solubilizing rhizobacteria and rock phosphate on nitrogen and phosphorus acquisition by medicago sativa
New Phytologist, 1998Co-Authors: M Toro, R Azcon, J M BareaAbstract:A pot experiment was designed to evaluate the interactive effects of multiple microbial inoculation treatments and rock phosphate (RP) application on N and P acquisition by alfalfa plants using 15N and 32P isotopes. The microbial inocula consisted of a wild type (WT) Rhizobium meliloti strain, its genetically modified (GM) derivative, which had an enhanced competitiveness, the arbuscular mycorrhizal (AM) fungus Glomus mosseae (Nicol. and Gerd.) Gerd. and Trappe, and a phosphate-Solubilizing rhizobacterium (Enterobacter sp.). Inoculated micro-organisms became established in the root tissues and/or in the rhizosphere soil of alfalfa plants (Medicago sativa L.). The GM Rhizobium strain did not interfere with AM formation. Inoculated phosphate-Solubilizing rhizobacteria established in the alfalfa rhizosphere, but the level of establishment was lower where the natural population of phosphate-Solubilizing bacteria was stimulated by AM inoculation and RP application. The stimulation of these indigenous bacteria was also greater in the rhizosphere of alfalfa nodulated by the GM Rhizobium. Improvements in N and P accumulation in alfalfa corroborate beneficial effects of the improved GM Rhizobium on AM performance, in RP-amended plants. Inoculation with Enterobacter did not improve the AM effect on N or P accumulation in the RP-added soil, but it did in the non RP-amended controls. Measurements of the 15N∶14N ratio in plant shoots indicated enhanced N2 fixation rates in Rhizobium-inoculated AM-plants, over that achieved by the same Rhizobium strain in non-mycorrhizal plants. Regardless of the Rhizobium strain and of whether or not RP was added, AM-inoculated plants showed a lower specific activity (32P∶31P) than did their comparable non-mycorrhizal controls, suggesting that the plant was using otherwise unavailable P sources. The phosphate-Solubilizing, AM-associated, microbiota could in fact release phosphate ions, either from the added RP or from the indigenous ‘less-available’ phosphate. Deficiency in Ca concentration in soil solution in the neutral test soil might benefit P solubilization. The proportion of plant P derived either from the labelled soil P (labile P pool) or from RP was similar for AM inoculated and non-mycorrhizal controls (without Enterobacter inoculation) for each Rhizobium strain, but the total P uptake, regardless of the P source, was far higher in AM-plants. Enterobacter inoculation seems to improve the use of RP in the rhizosphere of non-mycorrhizal plants inoculated with the WT Rhizobium.
R Azcon - One of the best experts on this subject based on the ideXlab platform.
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the application of isotopic 32p and 15n dilution techniques to evaluate the interactive effect of phosphate Solubilizing rhizobacteria mycorrhizal fungi and rhizobium to improve the agronomic efficiency of rock phosphate for legume crops
Nutrient Cycling in Agroecosystems, 2002Co-Authors: J M Barea, M Toro, M O Orozco, E Campos, R AzconAbstract:A pot experiment was designed to evaluate the interactive effects of multifunctional microbial inoculation treatments and rock phosphate (RP) application on N and P uptake by alfalfa through the use of 15N and 32P isotopic dilution approaches. The microbial inocula consisted of a wild type (WT) Rhizobium meliloti strain, the arbuscular mycorrhizal (AM) fungus Glomus mosseae (Nicol. and Gerd.) Gerd. and Trappe, and a phosphate Solubilizing rhizobacterium (Enterobacter sp.). Inoculated microorganisms were established in the root tissues and/or in the rhizosphere soil of alfalfa plants (Medicago sativa L.). Improvements in N and P accumulation in alfalfa corroborate beneficial effects of Rhizobium and AM interactions. Inoculation with selected rhizobacteria improved the AM effect on N or P accumulation in both the RP-added soil and in the non RP-amended controls. Measurements of the 15N/14N ratio in plant shoots indicate an enhancement of the N2 fixation rates in Rhizobium-inoculated AM-plants, over that achieved by Rhizobium in non-mycorrhizal plants. Whether or not RP was added, AM-inoculated plants showed a lower specific activity (32P/31P) than did their comparable non-mycorrhizal controls, suggesting that the plant was using otherwise unavailable P sources. The phosphate-Solubilizing, AM-associated, microbiota could in fact release phosphate ions, either from the added RP or from the indigenous ``less-available'' soil phosphate. A low Ca concentrations in the test soil may have benefited P solubilization. Under field conditions, the inoculation with AM fungi significantly increased plant biomass and N and P accumulation in plant tissues. Phosphate-Solubilizing rhizobacteria improved mycorrhizal responses in soil dually receiving RP and organic matter amendments. Organic matter addition favoured RP solubilization. This, together with a tailored microbial inoculation, increased the agronomic efficiency of RP in the test soil that was Ca deficient at neutral pH.
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the use of isotopic dilution techniques to evaluate the interactive effects of rhizobium genotype mycorrhizal fungi phosphate Solubilizing rhizobacteria and rock phosphate on nitrogen and phosphorus acquisition by medicago sativa
New Phytologist, 1998Co-Authors: M Toro, R Azcon, J M BareaAbstract:A pot experiment was designed to evaluate the interactive effects of multiple microbial inoculation treatments and rock phosphate (RP) application on N and P acquisition by alfalfa plants using 15N and 32P isotopes. The microbial inocula consisted of a wild type (WT) Rhizobium meliloti strain, its genetically modified (GM) derivative, which had an enhanced competitiveness, the arbuscular mycorrhizal (AM) fungus Glomus mosseae (Nicol. and Gerd.) Gerd. and Trappe, and a phosphate-Solubilizing rhizobacterium (Enterobacter sp.). Inoculated micro-organisms became established in the root tissues and/or in the rhizosphere soil of alfalfa plants (Medicago sativa L.). The GM Rhizobium strain did not interfere with AM formation. Inoculated phosphate-Solubilizing rhizobacteria established in the alfalfa rhizosphere, but the level of establishment was lower where the natural population of phosphate-Solubilizing bacteria was stimulated by AM inoculation and RP application. The stimulation of these indigenous bacteria was also greater in the rhizosphere of alfalfa nodulated by the GM Rhizobium. Improvements in N and P accumulation in alfalfa corroborate beneficial effects of the improved GM Rhizobium on AM performance, in RP-amended plants. Inoculation with Enterobacter did not improve the AM effect on N or P accumulation in the RP-added soil, but it did in the non RP-amended controls. Measurements of the 15N∶14N ratio in plant shoots indicated enhanced N2 fixation rates in Rhizobium-inoculated AM-plants, over that achieved by the same Rhizobium strain in non-mycorrhizal plants. Regardless of the Rhizobium strain and of whether or not RP was added, AM-inoculated plants showed a lower specific activity (32P∶31P) than did their comparable non-mycorrhizal controls, suggesting that the plant was using otherwise unavailable P sources. The phosphate-Solubilizing, AM-associated, microbiota could in fact release phosphate ions, either from the added RP or from the indigenous ‘less-available’ phosphate. Deficiency in Ca concentration in soil solution in the neutral test soil might benefit P solubilization. The proportion of plant P derived either from the labelled soil P (labile P pool) or from RP was similar for AM inoculated and non-mycorrhizal controls (without Enterobacter inoculation) for each Rhizobium strain, but the total P uptake, regardless of the P source, was far higher in AM-plants. Enterobacter inoculation seems to improve the use of RP in the rhizosphere of non-mycorrhizal plants inoculated with the WT Rhizobium.
Ravi Naidu - One of the best experts on this subject based on the ideXlab platform.
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concomitant rock phosphate dissolution and lead immobilization by phosphate Solubilizing bacteria enterobacter sp
Journal of Environmental Management, 2011Co-Authors: Jin Hee Park, Nanthi Bolan, Mallavarapu Megharaj, Ravi NaiduAbstract:Abstract This paper examines the potential value of phosphate Solubilizing bacteria (Enterobacter cloacae) in the dissolution of rock phosphate (RP) and subsequent immobilization of lead (Pb) in both bacterial growth medium and soils. Enterobacter sp. showed resistance to Pb and the bacterium solubilized 17.5% of RP in the growth medium. Entrobacter sp. did not enhance Pb immobilization in solution because of acidification of bacterial medium, thereby inhibiting the formation of P-induced Pb precipitation. However, in the case of soil, Enterobacter sp. increased Pb immobilization by 6.98, 25.6 and 32.0% with the RP level of 200, 800 and 1600 mg P/kg, respectively. The immobilization of Pb in Pb-spiked soils was attributed to pyromorphite formation as indicated by XRD analysis. Inoculation of phosphate Solubilizing bacteria with RP in soil can be used as an alternative technique to soluble P compounds which can cause eutrophication of surface water.
Nikolay Vassilev - One of the best experts on this subject based on the ideXlab platform.
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multifunctional properties of phosphate Solubilizing microorganisms grown on agro industrial wastes in fermentation and soil conditions
Applied Microbiology and Biotechnology, 2010Co-Authors: Maria Vassileva, Mercedes Serrano, V Bravo, E Jurado, Iana Nikolaeva, Vanessa Martos, Nikolay VassilevAbstract:One of the most studied approaches in solubilization of insoluble phosphates is the biological treatment of rock phosphates. In recent years, various techniques for rock phosphate solubilization have been proposed, with increasing emphasis on application of P-Solubilizing microorganisms. The P-Solubilizing activity is determined by the microbial biochemical ability to produce and release metabolites with metal-chelating functions. In a number of studies, we have shown that agro-industrial wastes can be efficiently used as substrates in solubilization of phosphate rocks. These processes were carried out employing various technologies including solid-state and submerged fermentations including immobilized cells. The review paper deals critically with several novel trends in exploring various properties of the above microbial/agro-wastes/rock phosphate systems. The major idea is to describe how a single P-Solubilizing microorganism manifests wide range of metabolic abilities in different environments. In fermentation conditions, P-Solubilizing microorganisms were found to produce various enzymes, siderophores, and plant hormones. Further introduction of the resulting biotechnological products into soil-plant systems resulted in significantly higher plant growth, enhanced soil properties, and biological (including biocontrol) activity. Application of these bio-products in bioremediation of disturbed (heavy metal contaminated and desertified) soils is based on another important part of their multifunctional properties.
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simultaneous p Solubilizing and biocontrol activity of microorganisms potentials and future trends
Applied Microbiology and Biotechnology, 2006Co-Authors: Nikolay Vassilev, Maria Vassileva, Iana NikolaevaAbstract:Phosphate (P)-Solubilizing microorganisms as a group form an important part of the microorganisms, which benefit plant growth and development. Growth promotion and increased uptake of phosphate are not the only mechanisms by which these microorganisms exert a positive effect on plants. Microbially mediated solubilization of insoluble phosphates through release of organic acids is often combined with production of other metabolites, which take part in biological control against soilborne phytopathogens. In vitro studies show the potential of P-Solubilizing microorganisms for the simultaneous synthesis and release of pathogen-suppressing metabolites, mainly siderophores, phytohormones, and lytic enzymes. Further trends in this field are discussed, suggesting a number of biotechnological approaches through physiological and biochemical studies using various microorganisms.
Sung Cheol Yoon - One of the best experts on this subject based on the ideXlab platform.
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effects of Solubilizing group modification in fullerene bis adducts on normal and inverted type polymer solar cells
Chemistry of Materials, 2012Co-Authors: Hyunbum Kang, Sung Cheol YoonAbstract:Structural control of Solubilizing side groups in fullerene-based electron acceptors is critically important to optimize their performance in bulk heterojunction (BHJ)-type polymer solar cell (PSC) devices. The structural changes of fullerene derivatives affect not only their optical and electrochemical properties but also their solubility and miscibility with electron donor polymers. Herein, we synthesized a series of o-xylenyl C60 bis-adduct (OXCBA) derivatives with different Solubilizing side groups to systematically investigate the effects of fullerene derivative structures on the photovoltaic properties of PSCs. The xylenyl side groups on the OXCBA were modified to produce several different OXCBA derivatives in which the xylenyl groups were functionalized with fluorine (FXCBA), nitro (NXCBA), methoxy and bromine (BMXCBA), and phenyl groups (ACBA). End group modifications of OXCBA dramatically affect photovoltaic performance in blend films with poly(3-hexylthiophene) (P3HT), resulting in power convers...
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Facile Synthesis of o -Xylenyl Fullerene Multiadducts for High Open Circuit Voltage and Efficient Polymer Solar Cells
Chemistry of Materials, 2011Co-Authors: Ki Hyun Kim, Hyunbum Kang, So Yeon Nam, Pan Seok Kim, Sung Cheol Yoon, Jaewook Jung, Changjin Lee, Chul-hee Cho, Bumjoon J. KimAbstract:The ability to control the lowest unoccupied molecular orbital (LUMO) level of an electron-accepting material is a critical parameter for producing highly efficient polymer solar cells (PSCs). Soluble bis-adducts of C60 have great potential for improving the VOC in PSCs because of their high LUMO level. In this work, we have developed a novel o-xylenyl C60 bis-adduct (OXCBA) via a 4 + 2 cycloaddition between C60 and an irreversible diene intermediate from α,α?-dibromo-o-xylene. OXCBA was successfully applied as the electron acceptor with poly(3-hexylthiophene) (P3HT) in a PSC, showing a high efficiency of 5.31% with VOC of 0.83 V. This composite showed a nearly 50% enhancement in efficiency compared to the P3HT:PCBM control device (3.68% with VOC of 0.59 V). Furthermore, tuning the molar ratio between C60 and the α,α?-dibromo-o-xylene group from 1:1 to 1:3 in the reaction scheme enables facile control over the number of o-xylenyl Solubilizing groups ultimately tethered to the fullerene, thus producing o-xylenyl C60 mono-, bis-, and tris-adducts (OXCMA, OXCBA, and OXCTA) with different LUMO levels. As the number of Solubilizing groups increased, VOC values of the P3HT-based BHJ solar cells increased from 0.63 V (OXCMA) to 0.83 V (OXCBA) to 0.98 V (OXCTA). This series of o-xylenyl C60 multiadducts provides a model system for investigating the molecular structure-device function relationship, especially with respect to changes in the number of Solubilizing groups on the electron acceptor. The ability to control the lowest unoccupied molecular orbital (LUMO) level of an electron-accepting material is a critical parameter for producing highly efficient polymer solar cells (PSCs). Soluble bis-adducts of C60 have great potential for improving the VOC in PSCs because of their high LUMO level. In this work, we have developed a novel o-xylenyl C60 bis-adduct (OXCBA) via a 4 + 2 cycloaddition between C60 and an irreversible diene intermediate from α,α?-dibromo-o-xylene. OXCBA was successfully applied as the electron acceptor with poly(3-hexylthiophene) (P3HT) in a PSC, showing a high efficiency of 5.31% with VOC of 0.83 V. This composite showed a nearly 50% enhancement in efficiency compared to the P3HT:PCBM control device (3.68% with VOC of 0.59 V). Furthermore, tuning the molar ratio between C60 and the α,α?-dibromo-o-xylene group from 1:1 to 1:3 in the reaction scheme enables facile control over the number of o-xylenyl Solubilizing groups ultimately tethered to the fullerene, thus producing o-xylenyl C60 mono-, bis-, and tris-adducts (OXCMA, OXCBA, and OXCTA) with different LUMO levels. As the number of Solubilizing groups increased, VOC values of the P3HT-based BHJ solar cells increased from 0.63 V (OXCMA) to 0.83 V (OXCBA) to 0.98 V (OXCTA). This series of o-xylenyl C60 multiadducts provides a model system for investigating the molecular structure-device function relationship, especially with respect to changes in the number of Solubilizing groups on the electron acceptor.
