The relationship between Solidago canadensis L. invasion and soil microbial community diversity including functional and structure diversities was studied across the invasive gradients varying from 0 to 40%, 80%, and ...The relationship between Solidago canadensis L. invasion and soil microbial community diversity including functional and structure diversities was studied across the invasive gradients varying from 0 to 40%, 80%, and 100% coverage of Solidago canadensis L. using sole carbon source utilization profiles analyses, principle component analysis （PCA） and phospholipid fatty acids （PLFA） profiles analyses. The results show the characteristics of soil microbial community functional and structure diversity in invaded soils strongly changed by Solidago canadensis L. invasion. Solidago canadensis L. invasion tended to result in higher substrate richness, and functional diversity. As compared to the native and ecotones, average utilization of specific substrate guilds of soil microbe was the highest in Solidago canadensis L. monoculture. Soil microbial functional diversity in Solidago canadensis L. monoculture was distinctly separated from the native area and the ecotones. Aerobic bacteria, fungi and actinomycetes population significantly increased but anaerobic bacteria decreased in the soil with Solidago canadensis L. monoculture. The ratio of cyl9：0 to 18：1 co7 gradually declined but mono/sat and fung/bact PLFAs increased when Solidago canadensis L. became more dominant. The microbial community composition clearly separated the native soil from the invaded soils by PCA analysis, especially 18： lco7c, 16： lco7t, 16： lco5c and 18：2co6, 9 were present in higher concentrations for exotic soil. In conclusion, Solidago canadensis L. invasion could create better soil conditions by improving soil microbial community structure and functional diversity, which in turn was more conducive to the growth ofSolidago canadensis L.展开更多
Phytoplankton and environmental variables were measured monthly from July 2009 to August 2011 in the Maixi River from the estuary to Baihua Reservoir in the Maotiao River catchment, southwestern China, to understand p...Phytoplankton and environmental variables were measured monthly from July 2009 to August 2011 in the Maixi River from the estuary to Baihua Reservoir in the Maotiao River catchment, southwestern China, to understand phytoplankton community structure and environmental factors. The relationship between phytoplankton community structure and environmental factors including hydrological, meteorological, physical, and chemical variables were explored using multivariate analysis. A total of 81 taxa of phytoplankton were identified, which were mainly composed of chlorophyta, bacillariophyta, and cyanobacteria. The phytoplankton community was dominated by Pseudanabaena limnetica during summer and fall and by Cyclotella meneghiniana during winter and spring. The abundance of phytoplankton ranged from 0.24~ 104 cells/L to 33.45x 106 cells/L, with the minimum occurring during February 2010 and the maximum during July 2009. The phytoplankton community was dominated mainly by cyanobacteria from April to September, and by bacillariophyta and pyrrophyta from October to March. Canonical correspondence analysis showed that temperature, pH values, and orthophosphate were the most important driving factors regulating the composition and dynamics of the phytoplankton community in the estuary. Cyanobacteria and euglenophyta abundance and biomass were affected mainly by temperature and pH values, while most chlorophyta and bacillariophyta were influenced by the concentrations of nutrients.展开更多
On the basis of multifaceted investigations of approximately 600 phytosociological surveys of foxtail meadows taken in years 2002-2012 in river valleys with the assistance of the Braun-Blanquet method, the authors car...On the basis of multifaceted investigations of approximately 600 phytosociological surveys of foxtail meadows taken in years 2002-2012 in river valleys with the assistance of the Braun-Blanquet method, the authors carried out evaluation of the floristic composition with respect to phytosociological structure, floristic variability, degree of synanthropisation and life form structures. In addition, they ascertained the dependence of floristic variability of Alopecuretum pratensis phytocenoses on site conditions determined using： the phytoindication method and the laboratory analyses assessed the soil content of available forms of P and K and of Mg. The greatest areas among the recognised syntaxons are taken up by patches of a typical sub-association developed in fresh sites on soils of lightly acid reaction and moderate nitrogen availability. Floristic variability of Alopecuretum pratensis is characterised by： presence in the phytosociological structure of species characteristic for other syntaxons, floristic abundance and botanical structure, domination of species of the 1 st and 2nd degree of stability, high proportion of synanthropic species, values of the floristic diversity index （H＇）, natural and fodder score values. Geobotanical variability of foxtail meadows confirms difficulties with unequivocal determination of the systematic position of the Alopecuretum pratensis association.展开更多
基金Project(2009QNA6015) supported by the Fundamental Research Funds for the Central Universities of ChinaProject(Y3110055)supported by the Natural Science Foundation of Zhejiang Province,ChinaProject(Y200803219) supported by the Foundation of Zhejiang Educational Committee of China
文摘The relationship between Solidago canadensis L. invasion and soil microbial community diversity including functional and structure diversities was studied across the invasive gradients varying from 0 to 40%, 80%, and 100% coverage of Solidago canadensis L. using sole carbon source utilization profiles analyses, principle component analysis （PCA） and phospholipid fatty acids （PLFA） profiles analyses. The results show the characteristics of soil microbial community functional and structure diversity in invaded soils strongly changed by Solidago canadensis L. invasion. Solidago canadensis L. invasion tended to result in higher substrate richness, and functional diversity. As compared to the native and ecotones, average utilization of specific substrate guilds of soil microbe was the highest in Solidago canadensis L. monoculture. Soil microbial functional diversity in Solidago canadensis L. monoculture was distinctly separated from the native area and the ecotones. Aerobic bacteria, fungi and actinomycetes population significantly increased but anaerobic bacteria decreased in the soil with Solidago canadensis L. monoculture. The ratio of cyl9：0 to 18：1 co7 gradually declined but mono/sat and fung/bact PLFAs increased when Solidago canadensis L. became more dominant. The microbial community composition clearly separated the native soil from the invaded soils by PCA analysis, especially 18： lco7c, 16： lco7t, 16： lco5c and 18：2co6, 9 were present in higher concentrations for exotic soil. In conclusion, Solidago canadensis L. invasion could create better soil conditions by improving soil microbial community structure and functional diversity, which in turn was more conducive to the growth ofSolidago canadensis L.
基金Supported by the National Natural Science Foundation of China(No.411063005)the National Basic Research Program of China(973 Program)(No.2012CB426506)the Science and Technology Committee of Guizhou Foundation(Nos.[2011]7028,[2012]7021)
文摘Phytoplankton and environmental variables were measured monthly from July 2009 to August 2011 in the Maixi River from the estuary to Baihua Reservoir in the Maotiao River catchment, southwestern China, to understand phytoplankton community structure and environmental factors. The relationship between phytoplankton community structure and environmental factors including hydrological, meteorological, physical, and chemical variables were explored using multivariate analysis. A total of 81 taxa of phytoplankton were identified, which were mainly composed of chlorophyta, bacillariophyta, and cyanobacteria. The phytoplankton community was dominated by Pseudanabaena limnetica during summer and fall and by Cyclotella meneghiniana during winter and spring. The abundance of phytoplankton ranged from 0.24~ 104 cells/L to 33.45x 106 cells/L, with the minimum occurring during February 2010 and the maximum during July 2009. The phytoplankton community was dominated mainly by cyanobacteria from April to September, and by bacillariophyta and pyrrophyta from October to March. Canonical correspondence analysis showed that temperature, pH values, and orthophosphate were the most important driving factors regulating the composition and dynamics of the phytoplankton community in the estuary. Cyanobacteria and euglenophyta abundance and biomass were affected mainly by temperature and pH values, while most chlorophyta and bacillariophyta were influenced by the concentrations of nutrients.
文摘On the basis of multifaceted investigations of approximately 600 phytosociological surveys of foxtail meadows taken in years 2002-2012 in river valleys with the assistance of the Braun-Blanquet method, the authors carried out evaluation of the floristic composition with respect to phytosociological structure, floristic variability, degree of synanthropisation and life form structures. In addition, they ascertained the dependence of floristic variability of Alopecuretum pratensis phytocenoses on site conditions determined using： the phytoindication method and the laboratory analyses assessed the soil content of available forms of P and K and of Mg. The greatest areas among the recognised syntaxons are taken up by patches of a typical sub-association developed in fresh sites on soils of lightly acid reaction and moderate nitrogen availability. Floristic variability of Alopecuretum pratensis is characterised by： presence in the phytosociological structure of species characteristic for other syntaxons, floristic abundance and botanical structure, domination of species of the 1 st and 2nd degree of stability, high proportion of synanthropic species, values of the floristic diversity index （H＇）, natural and fodder score values. Geobotanical variability of foxtail meadows confirms difficulties with unequivocal determination of the systematic position of the Alopecuretum pratensis association.
