A few soil microorganisms can convert insoluble forms of phosphorus （P） to an accessible form to increase plant yields The objectives of this study were to isolate, screen and identify the phosphobacteria, i.e., pho...A few soil microorganisms can convert insoluble forms of phosphorus （P） to an accessible form to increase plant yields The objectives of this study were to isolate, screen and identify the phosphobacteria, i.e., phosphate-solubilizing bacteria （PSB） and phosphate-mineralizing bacteria （PMB）, in some poplar plantations and to select potential microbial inoculants that could increase the P uptake by plants. Seventy four PSB strains and 138 PMB strains were preliminarily screened from 797＂colonies isolated from the rhizosphere soil of poplar by the visible decolorization in the National Botanical Research Institute＇s phosphate growth medium （NBRIP） containing a pH indicator of bromophenol and by the clear/halo zone on yeast malt agar plate, respectively. Then, based on the solubilization of Ca3（PO4）2 in liquid NBRIP medium and the mineralization of lecithin in liquid Menkina medium, 15 PS1R strains and 7 PMB strains were further determined for their abilities to solubilize Ca3（PO4）2 and to mineralize lecithin. The results showed that the 15 PSB strains exhibited inorganic P-solubilizing abilities ranging between 376.62 and 669.56 mg L-1 and the 7 PMB strains exhibited organic P-mineralizing abilities vaxying from 0.32 to 1.56 mg L-1 three days after incubation. Three of PSB strains with the highest P-solubilizing ability, named JW-JS1, JW-JS2 and JW-SX2, were all preliminarily identified as Pseudomonas ftuorescens, while two of PMB strains with the highest P-mineralizing ability, named JYZ-SD1 and JYT-JS2, were preliminarily identified as Bacillus cereus and Bacillus subtilis, respectively. All the efficient PSB and PMB strains should be further studied under both pot culture and field conditions to test their beneficial effects on poplar.展开更多
SiC窑具材料浸渍Ca3(PO4)2与AlPO4混合饱和溶液,能填充气孔,降低气孔率,阻碍O2的扩散,能增加SiC窑具抗氧化性,延长其使用寿命.浸渍次数越多,氧化速度越小.浸渍1～4次的氧化速度常数比值为:Ki混:K2混:K3混:K4混=1.44×10-7:1.16 x 10...SiC窑具材料浸渍Ca3(PO4)2与AlPO4混合饱和溶液,能填充气孔,降低气孔率,阻碍O2的扩散,能增加SiC窑具抗氧化性,延长其使用寿命.浸渍次数越多,氧化速度越小.浸渍1～4次的氧化速度常数比值为:Ki混:K2混:K3混:K4混=1.44×10-7:1.16 x 10-7:1.02×10 7:0.87×107=1.66:1.33:1.1 7:1,浸渍混合饱和溶液的抗氧化能力比浸渍Ca3(PO4)2饱和溶液强.展开更多
The mechanism of removing phosphate by MSWI(municipal solid waste incineration)fly ash was investigated by SEM(scanning electron microscopy)with EDS(energy dispersion spectrum),XRD(X-ray diffraction),FT-IR(Fourier tra...The mechanism of removing phosphate by MSWI(municipal solid waste incineration)fly ash was investigated by SEM(scanning electron microscopy)with EDS(energy dispersion spectrum),XRD(X-ray diffraction),FT-IR(Fourier transform infrared spectroscopy),BET(specific surface area),and BJH(pore size distribution).The results indicate that the removal rate of phosphate(100 mg/L)in 50 mL phosphorus wastewater reaches at 99.9% as the dosage of MSWI fly ash being 0.9000 g under room temperature.The specific surface area of MSWI fly ash is less than 6.1 m2/g and the total pore volume is below 0.021 cm3/g,suggesting that the absorption capacity of calcite is too weak to play an important role in phosphate removal.SEM images show that drastic changes had taken place on its specific surface shape after reaction,and EDS tests indicate that some phosphate precipitates are formed and attached onto MSWI fly ash particles.Chemical precipitation is the main manner of phosphate removal and the main reaction is: 3Ca2++2 PO4 3-+xH2O→Ca3(PO4)2↓·xH2O.Besides,XRD tests show that the composition of MSWI fly ash is complex,but CaSO4 is likely to be the main source of Ca2+.The soluble heavy metals in MSWI fly ash are stabilized by phosphate.展开更多
Phosphorus （P） starvation is highly notorious for limiting plant growth around the globe. To combat P-starvation, plants constantly sense the changes in their environment, and elicit an elegant myriad of plastic res...Phosphorus （P） starvation is highly notorious for limiting plant growth around the globe. To combat P-starvation, plants constantly sense the changes in their environment, and elicit an elegant myriad of plastic responses and rescue strategies to enhance P-solublization and acquisition from bound soil P-forms. Relative growth responses, P-solublization and P- acquisition ability of 14 diverse Brassica cultivars grown with sparingly soluble P-sources （Rock-P （RP） and Ca3（PO4）2 （TCP）） were evaluated in a solution culture experiment. Cultivars showed considerable genetic diversity in terms of biomass accumulation, concentration and contents of P and Ca in shoots and roots, P-stress factor （PSF） and P use efficiency. Cultivars showed variable P-stress tolerance, and cultivars depicting low PSF and high P-efficiency values were better adaptable to P-starvation. In experiment 2, after initial feeding on optimum nutrition for 12 d after transplanting （DAT）, class-I （low P-tolerant （Oscar and Con-II）） and class-II （low P-sensitive （Gold Rush and RL-18）） cultivars were exposed to P-free environment for 25 d. All of the cultivars remobilized P from above ground parts to their roots during growth in P-free environment, the magnitude of which was variable in tested cultivars. P-concentrations （[P]s） at 37 DAT were higher in developing compared with developed leaves. Translocation of absorbed P from metabolically inactive to active sites in P- stressed plants may have helped class-I cultivars to establish a better rooting system, which provided a basis for enhanced P-utilization efficiency （PUE） and tolerance against P-stress. By supplying TCP and RP spatially separated from other nutrients in split root study, class-I cultivars were still able to mobilize RP and TCP more efficiently compared with class-II cultivars. To compare the growth behavior under P-stress, cultivars were grown in pots for 41 d after sowing, using a soil low in P （NaHCO3-extractable P = 3.97 mg/kg, M展开更多
Mg-6%Zn-10%β-Ca3(PO4)2 composite was prepared through powder metallurgy methods with different chitosan coatings on its surface. The properties of the chitosan coatings on the surface of Mg-6%Zn-10%β-Ca3(PO4)2 compo...Mg-6%Zn-10%β-Ca3(PO4)2 composite was prepared through powder metallurgy methods with different chitosan coatings on its surface. The properties of the chitosan coatings on the surface of Mg-6%Zn-10%β-Ca3(PO4)2 composite, such as the adhesion ability, the corrosion behavior and the cytotoxicity properties, were investigated, and the microstructure of the chitosan coating was observed by scanning electron microscope(SEM). The results show that chitosan coating improves the corrosion resistance of the magnesium composite specimens significantly. Mg-6%Zn-10%β-Ca3(PO4)2 composite specimens exhibit good corrosion resistance and low p H values in simulated body fluid(SBF) at 37 °C in the immersion test with 7-layer chitosan coating whose relative molecular mass is 30×104 Da. The cytotoxicity tests indicate that Mg-6%Zn-10%β-Ca3(PO4)2 with chitosan coating is nontoxic with a cytotoxicity grade of zero against L-929 cells, which is better than that of uncoated composites.展开更多
基金Supported by the Program for Science and Technology Development of Jiangsu Province,China (No. BE2008393)the InnovationPlan for Graduate Students of Jiangsu Province,China (No. CX08B 028Z)the Public Welfare Scientific Special of State ForestryAdministration in China (No. 201004061)
文摘A few soil microorganisms can convert insoluble forms of phosphorus （P） to an accessible form to increase plant yields The objectives of this study were to isolate, screen and identify the phosphobacteria, i.e., phosphate-solubilizing bacteria （PSB） and phosphate-mineralizing bacteria （PMB）, in some poplar plantations and to select potential microbial inoculants that could increase the P uptake by plants. Seventy four PSB strains and 138 PMB strains were preliminarily screened from 797＂colonies isolated from the rhizosphere soil of poplar by the visible decolorization in the National Botanical Research Institute＇s phosphate growth medium （NBRIP） containing a pH indicator of bromophenol and by the clear/halo zone on yeast malt agar plate, respectively. Then, based on the solubilization of Ca3（PO4）2 in liquid NBRIP medium and the mineralization of lecithin in liquid Menkina medium, 15 PS1R strains and 7 PMB strains were further determined for their abilities to solubilize Ca3（PO4）2 and to mineralize lecithin. The results showed that the 15 PSB strains exhibited inorganic P-solubilizing abilities ranging between 376.62 and 669.56 mg L-1 and the 7 PMB strains exhibited organic P-mineralizing abilities vaxying from 0.32 to 1.56 mg L-1 three days after incubation. Three of PSB strains with the highest P-solubilizing ability, named JW-JS1, JW-JS2 and JW-SX2, were all preliminarily identified as Pseudomonas ftuorescens, while two of PMB strains with the highest P-mineralizing ability, named JYZ-SD1 and JYT-JS2, were preliminarily identified as Bacillus cereus and Bacillus subtilis, respectively. All the efficient PSB and PMB strains should be further studied under both pot culture and field conditions to test their beneficial effects on poplar.
文摘SiC窑具材料浸渍Ca3(PO4)2与AlPO4混合饱和溶液,能填充气孔,降低气孔率,阻碍O2的扩散,能增加SiC窑具抗氧化性,延长其使用寿命.浸渍次数越多,氧化速度越小.浸渍1～4次的氧化速度常数比值为:Ki混:K2混:K3混:K4混=1.44×10-7:1.16 x 10-7:1.02×10 7:0.87×107=1.66:1.33:1.1 7:1,浸渍混合饱和溶液的抗氧化能力比浸渍Ca3(PO4)2饱和溶液强.
基金Projects(51108100,50808184)supported by the National Natural Science Foundation of ChinaProject(100Z007)supported by the Ministry of Education of China+1 种基金Project(200103YB020)supported by Foundation of Guangxi Educational Committee,ChinaProject supported by Guangxi Normal University Education Development Foundation for Young Scholars,China
文摘The mechanism of removing phosphate by MSWI(municipal solid waste incineration)fly ash was investigated by SEM(scanning electron microscopy)with EDS(energy dispersion spectrum),XRD(X-ray diffraction),FT-IR(Fourier transform infrared spectroscopy),BET(specific surface area),and BJH(pore size distribution).The results indicate that the removal rate of phosphate(100 mg/L)in 50 mL phosphorus wastewater reaches at 99.9% as the dosage of MSWI fly ash being 0.9000 g under room temperature.The specific surface area of MSWI fly ash is less than 6.1 m2/g and the total pore volume is below 0.021 cm3/g,suggesting that the absorption capacity of calcite is too weak to play an important role in phosphate removal.SEM images show that drastic changes had taken place on its specific surface shape after reaction,and EDS tests indicate that some phosphate precipitates are formed and attached onto MSWI fly ash particles.Chemical precipitation is the main manner of phosphate removal and the main reaction is: 3Ca2++2 PO4 3-+xH2O→Ca3(PO4)2↓·xH2O.Besides,XRD tests show that the composition of MSWI fly ash is complex,but CaSO4 is likely to be the main source of Ca2+.The soluble heavy metals in MSWI fly ash are stabilized by phosphate.
基金the Japan Society for the Promotion of Science (JSPS) for financial support, which enabled him to pursue this research work
文摘Phosphorus （P） starvation is highly notorious for limiting plant growth around the globe. To combat P-starvation, plants constantly sense the changes in their environment, and elicit an elegant myriad of plastic responses and rescue strategies to enhance P-solublization and acquisition from bound soil P-forms. Relative growth responses, P-solublization and P- acquisition ability of 14 diverse Brassica cultivars grown with sparingly soluble P-sources （Rock-P （RP） and Ca3（PO4）2 （TCP）） were evaluated in a solution culture experiment. Cultivars showed considerable genetic diversity in terms of biomass accumulation, concentration and contents of P and Ca in shoots and roots, P-stress factor （PSF） and P use efficiency. Cultivars showed variable P-stress tolerance, and cultivars depicting low PSF and high P-efficiency values were better adaptable to P-starvation. In experiment 2, after initial feeding on optimum nutrition for 12 d after transplanting （DAT）, class-I （low P-tolerant （Oscar and Con-II）） and class-II （low P-sensitive （Gold Rush and RL-18）） cultivars were exposed to P-free environment for 25 d. All of the cultivars remobilized P from above ground parts to their roots during growth in P-free environment, the magnitude of which was variable in tested cultivars. P-concentrations （[P]s） at 37 DAT were higher in developing compared with developed leaves. Translocation of absorbed P from metabolically inactive to active sites in P- stressed plants may have helped class-I cultivars to establish a better rooting system, which provided a basis for enhanced P-utilization efficiency （PUE） and tolerance against P-stress. By supplying TCP and RP spatially separated from other nutrients in split root study, class-I cultivars were still able to mobilize RP and TCP more efficiently compared with class-II cultivars. To compare the growth behavior under P-stress, cultivars were grown in pots for 41 d after sowing, using a soil low in P （NaHCO3-extractable P = 3.97 mg/kg, M
基金Project(2012zzts068) supported by the Fundamental Research Funds for the Central Universities of Central South University,ChinaProject(2010fj3091) supported by the Open Funding of State Key Laboratory of Powder Metallurgy and Science&Technology Foundation,China
文摘Mg-6%Zn-10%β-Ca3(PO4)2 composite was prepared through powder metallurgy methods with different chitosan coatings on its surface. The properties of the chitosan coatings on the surface of Mg-6%Zn-10%β-Ca3(PO4)2 composite, such as the adhesion ability, the corrosion behavior and the cytotoxicity properties, were investigated, and the microstructure of the chitosan coating was observed by scanning electron microscope(SEM). The results show that chitosan coating improves the corrosion resistance of the magnesium composite specimens significantly. Mg-6%Zn-10%β-Ca3(PO4)2 composite specimens exhibit good corrosion resistance and low p H values in simulated body fluid(SBF) at 37 °C in the immersion test with 7-layer chitosan coating whose relative molecular mass is 30×104 Da. The cytotoxicity tests indicate that Mg-6%Zn-10%β-Ca3(PO4)2 with chitosan coating is nontoxic with a cytotoxicity grade of zero against L-929 cells, which is better than that of uncoated composites.
