[Objective] The study aimed to isolate and screen efficient phosphorus-sol- ubilizing strains from the root soil of alfalfa in Guizhou, and investigate its growth promoting mechanism. [Method] Phosphorus solubilizing ...[Objective] The study aimed to isolate and screen efficient phosphorus-sol- ubilizing strains from the root soil of alfalfa in Guizhou, and investigate its growth promoting mechanism. [Method] Phosphorus solubilizing bacteria were isolated from rhizosphere of alfalfa with inorganic and organic phosphorous medium and the strains with higher capacity of dissolving phosphorus were screened through dissolv- ing phosphate zone and further researched. Meanwhile the phosphorus solubilizing capability of strains cultured in liquid medium was investigated by molybdenum blue colorimetric method. [Result] The capacity of dissolving calcium phosphate of 11 se- lected strains differed significantly and tended to be volatile from 150.40 to 268.20 μg/ml; phosphate solubilization capacity, IAA secretion and the pH of culture media did not show any significant correlation; all strains could produce IAA, and the se- cretion was from 12.09 to 22.16 μg/ml; the selected strains all could produce alka- line matter, and most of colonies were pale or milky white, irregular, opaque, jagged, flat and non-pigmented; utilization of carbon sources by different strains varied signifi- cantly. [Conclusion] The study laid the foundation for relieving phosphorus in unpro- ductive land, saving phosphate resources, reducing environmental pollution and pro- viding fertilizer in alfalfa production.展开更多
Understanding the coupling relationships among lake physicochemical properties,internal nutrient recycling,and related microbes is key for the control of freshwater eutrophication.In this study,seasonal variations in ...Understanding the coupling relationships among lake physicochemical properties,internal nutrient recycling,and related microbes is key for the control of freshwater eutrophication.In this study,seasonal variations in microorganisms at the sediment–water interface(SWI)of the eutrophic Lake Chaohu in China were analyzed,in order to reveal changes in phosphorus(P)-cycling-related microbes in the sediments and its association with internal P release during the cyanobacterial life cycle.The identified P-cycling-related microbes include phosphorus-solubilizing bacteria(PSB)(dominant of Bacillus,Thiobacillus and Acinetobacter),sulfate-reducing bacteria(SRB)(dominant of Sva0081_sediment_group,norank_c__Thermodesulfovibrionia and Desulfatiglans)and iron-reducing bacteria(FeRB)(dominant of Geothermobacter,Anaeromyxobacter,Thermoanaerobaculum and Clostridium_sensu_stricto_1).Increased PSB and reduced proportions of iron-aluminum–bound P(Fe/Al-P)and calcium–bound P(Ca-P)from the benthic stage to initial cyanobacterial growth indicated that internal phosphorus was released through the solubilization of Fe/Al-P and Ca-P by PSB.Growth of cyanobacteria was accompanied by cyanobacteria death,deposition,and degradation during early algal blooms,which increased SRB caused by high organic matter and the net deposition of phosphorus in the western lake.Conversely,phosphorus release in eastern lake was observed because of organic phosphorus mineralization.High linear discriminant analysis effect size of SRB and FeRB and the decreased Fe/Al-P in sediments indicated sulfide-mediated chemical iron reduction(SCIR)and FeRB-mediated microbial iron reduction mechanisms for internal phosphorus release during late algal blooms.The observed seasonal pattern of P-cycling-related microbes and its mediation on internal phosphorus release provides a foundation for internal P management in Lake Chaohu.展开更多
The research isolated phosphorus-soluble bacteria from different parts of ryegrasses and selected 7 bacteria performing better in solbilizing capacity. The test results showed that the capacity of phosphorus-solubiliz...The research isolated phosphorus-soluble bacteria from different parts of ryegrasses and selected 7 bacteria performing better in solbilizing capacity. The test results showed that the capacity of phosphorus-solubilizing tended to be volatile in the range from 135.27 to 187.87 μg/ml and the secreting capacity of IAA was in3.47-24.27 μg/ml. It is believed that Lp59, Lp61, Lp65, Lp69, Lp70 and Lp72 are potential for further development.展开更多
基金Supported by Key Agricultural Program of Guizhou Province([2009]3067)Science and Technology Foundation of Guizhou Province([2012]2199)~~
文摘[Objective] The study aimed to isolate and screen efficient phosphorus-sol- ubilizing strains from the root soil of alfalfa in Guizhou, and investigate its growth promoting mechanism. [Method] Phosphorus solubilizing bacteria were isolated from rhizosphere of alfalfa with inorganic and organic phosphorous medium and the strains with higher capacity of dissolving phosphorus were screened through dissolv- ing phosphate zone and further researched. Meanwhile the phosphorus solubilizing capability of strains cultured in liquid medium was investigated by molybdenum blue colorimetric method. [Result] The capacity of dissolving calcium phosphate of 11 se- lected strains differed significantly and tended to be volatile from 150.40 to 268.20 μg/ml; phosphate solubilization capacity, IAA secretion and the pH of culture media did not show any significant correlation; all strains could produce IAA, and the se- cretion was from 12.09 to 22.16 μg/ml; the selected strains all could produce alka- line matter, and most of colonies were pale or milky white, irregular, opaque, jagged, flat and non-pigmented; utilization of carbon sources by different strains varied signifi- cantly. [Conclusion] The study laid the foundation for relieving phosphorus in unpro- ductive land, saving phosphate resources, reducing environmental pollution and pro- viding fertilizer in alfalfa production.
基金supported by the National Natural Science Foundation of China(No.U22A20616).
文摘Understanding the coupling relationships among lake physicochemical properties,internal nutrient recycling,and related microbes is key for the control of freshwater eutrophication.In this study,seasonal variations in microorganisms at the sediment–water interface(SWI)of the eutrophic Lake Chaohu in China were analyzed,in order to reveal changes in phosphorus(P)-cycling-related microbes in the sediments and its association with internal P release during the cyanobacterial life cycle.The identified P-cycling-related microbes include phosphorus-solubilizing bacteria(PSB)(dominant of Bacillus,Thiobacillus and Acinetobacter),sulfate-reducing bacteria(SRB)(dominant of Sva0081_sediment_group,norank_c__Thermodesulfovibrionia and Desulfatiglans)and iron-reducing bacteria(FeRB)(dominant of Geothermobacter,Anaeromyxobacter,Thermoanaerobaculum and Clostridium_sensu_stricto_1).Increased PSB and reduced proportions of iron-aluminum–bound P(Fe/Al-P)and calcium–bound P(Ca-P)from the benthic stage to initial cyanobacterial growth indicated that internal phosphorus was released through the solubilization of Fe/Al-P and Ca-P by PSB.Growth of cyanobacteria was accompanied by cyanobacteria death,deposition,and degradation during early algal blooms,which increased SRB caused by high organic matter and the net deposition of phosphorus in the western lake.Conversely,phosphorus release in eastern lake was observed because of organic phosphorus mineralization.High linear discriminant analysis effect size of SRB and FeRB and the decreased Fe/Al-P in sediments indicated sulfide-mediated chemical iron reduction(SCIR)and FeRB-mediated microbial iron reduction mechanisms for internal phosphorus release during late algal blooms.The observed seasonal pattern of P-cycling-related microbes and its mediation on internal phosphorus release provides a foundation for internal P management in Lake Chaohu.
基金Supported by Social Development Projects in Guizhou Province(NY[2011]3104)System Reform Program of Guizhou Province(Z[2012]4005)~~
文摘The research isolated phosphorus-soluble bacteria from different parts of ryegrasses and selected 7 bacteria performing better in solbilizing capacity. The test results showed that the capacity of phosphorus-solubilizing tended to be volatile in the range from 135.27 to 187.87 μg/ml and the secreting capacity of IAA was in3.47-24.27 μg/ml. It is believed that Lp59, Lp61, Lp65, Lp69, Lp70 and Lp72 are potential for further development.
