Microorganisms being used in Cd-contaminated soil remediation have broad prospects in application.In order to obtain more Cd-tolerant microbial resources,paddy soils around lead-zinc tailings were collected to extract...Microorganisms being used in Cd-contaminated soil remediation have broad prospects in application.In order to obtain more Cd-tolerant microbial resources,paddy soils around lead-zinc tailings were collected to extract Cdtolerant bacterial strains by using the methods of enrichment culture,purification and gradient screening.The strains were identified by morphological and biochemical characteristics and 16S rDNA sequence analysis.The Cd-tolerance and Cdadsorption abilities were then analyzed.The results showed that 6 Cd-tolerant bacterial strains were isolated,3 strains could grow in solid medium which had a cadmium concentration of 700 mg/L.These three strains(i.e.KGJ,KDT,and TU)were members of the Pseudomonas genus(Pseudomonas sp.)identified by morphological and biochemical characteristics and 16S rDNA sequence analysis.The growth curve indicated that the growth rates of the strains were obviously inhibited under 250 mg/L cadmium treatment.The three strains were tolerant of cadmium concentrations over 250 mg/L for long periods of time up to the stationary phase,and TU had the strongest Cd-tolerance.The order of metal tolerance of TU to different heavy metals was Cd^2+ >Zn^2+ >Pb^2+respectively.Chemical analysis showed that the adsorption quantity of the 3 bacterial strains of KGJ,KDT,and TU were 7.596 mg/g,12.237 mg/g and 36.926 mg/g respectively by dry-weight,when the concentration of cadmium was 150 mg/L.All 3 strains had good tolerance and ability to adsorb cadmium,and therefore are considered important potential microbial resources for the remediation of Cd pollution in soil.展开更多
To evaluate the effects of γ irradiation on the edible quality of sun-cured crispy radish after γ irradiation, we measured volatile components, microstructure,color, and texture. Gamma irradiation had certain effect...To evaluate the effects of γ irradiation on the edible quality of sun-cured crispy radish after γ irradiation, we measured volatile components, microstructure,color, and texture. Gamma irradiation had certain effects on the composition and content of volatile components in sun-cured crispy radish, which increased the content of aldehydes, ketones and sulfur-containing substances. Increasing doses of irradiation caused declines in characteristics such as crispness, hardness,cohesiveness, and chewiness. Compared with the control, there were no obvious effects of γ irradiation on brightness L*, red-green value a* and yellow-blue value b*,and the total color difference ΔE was not significant. Scanning electron microscopy revealed that, after γ irradiation at a dose of 13.72 kGy, the vascular tissue in the radish root-skin was slightly damaged, and some small folds appeared on the cell wall of parenchymal cells in the flesh part, covered with a small amount of tiny particles. Considering the effects of γ irradiation on the quality of sun-cured crispy radish, low doses of γ irradiation are recommended, and this study can be a reference for the application of γ irradiation in the preservations of radish and similar vegetable products.展开更多
基金Supported by Hunan Key Research&Development Project(2016SK2056)~~
文摘Microorganisms being used in Cd-contaminated soil remediation have broad prospects in application.In order to obtain more Cd-tolerant microbial resources,paddy soils around lead-zinc tailings were collected to extract Cdtolerant bacterial strains by using the methods of enrichment culture,purification and gradient screening.The strains were identified by morphological and biochemical characteristics and 16S rDNA sequence analysis.The Cd-tolerance and Cdadsorption abilities were then analyzed.The results showed that 6 Cd-tolerant bacterial strains were isolated,3 strains could grow in solid medium which had a cadmium concentration of 700 mg/L.These three strains(i.e.KGJ,KDT,and TU)were members of the Pseudomonas genus(Pseudomonas sp.)identified by morphological and biochemical characteristics and 16S rDNA sequence analysis.The growth curve indicated that the growth rates of the strains were obviously inhibited under 250 mg/L cadmium treatment.The three strains were tolerant of cadmium concentrations over 250 mg/L for long periods of time up to the stationary phase,and TU had the strongest Cd-tolerance.The order of metal tolerance of TU to different heavy metals was Cd^2+ >Zn^2+ >Pb^2+respectively.Chemical analysis showed that the adsorption quantity of the 3 bacterial strains of KGJ,KDT,and TU were 7.596 mg/g,12.237 mg/g and 36.926 mg/g respectively by dry-weight,when the concentration of cadmium was 150 mg/L.All 3 strains had good tolerance and ability to adsorb cadmium,and therefore are considered important potential microbial resources for the remediation of Cd pollution in soil.
基金Supported by Agricultural Science and Technology Innovation Fund of Hunan Province(2017XC12)Scientific and Technological Innovation Project in Hunan Academy of Agricultural Sciences(2016QN11)+1 种基金Hunan Province Engineering Technology Research Center of Agricultural Biological Irradiation(2017PT03)Platform Scientific Fund Project(2016KF006)~~
文摘To evaluate the effects of γ irradiation on the edible quality of sun-cured crispy radish after γ irradiation, we measured volatile components, microstructure,color, and texture. Gamma irradiation had certain effects on the composition and content of volatile components in sun-cured crispy radish, which increased the content of aldehydes, ketones and sulfur-containing substances. Increasing doses of irradiation caused declines in characteristics such as crispness, hardness,cohesiveness, and chewiness. Compared with the control, there were no obvious effects of γ irradiation on brightness L*, red-green value a* and yellow-blue value b*,and the total color difference ΔE was not significant. Scanning electron microscopy revealed that, after γ irradiation at a dose of 13.72 kGy, the vascular tissue in the radish root-skin was slightly damaged, and some small folds appeared on the cell wall of parenchymal cells in the flesh part, covered with a small amount of tiny particles. Considering the effects of γ irradiation on the quality of sun-cured crispy radish, low doses of γ irradiation are recommended, and this study can be a reference for the application of γ irradiation in the preservations of radish and similar vegetable products.
