Tropical mountain ecosystems are usually colonized by numerous invasive plant species and represent an ideal‘natural laboratory’to study the effects of altitude on plant invasion.The aim of this study was to investi...Tropical mountain ecosystems are usually colonized by numerous invasive plant species and represent an ideal‘natural laboratory’to study the effects of altitude on plant invasion.The aim of this study was to investigate the soil chemical and microbiological properties along an altitudinal gradient on a mountain colonized by the invader Ageratina adenophora.Rhizosphere soil of A.adenophora was collected over an altitudinal gradient(1400–2400 m)in Ailao Shan,China.We determined soil organic carbon(C),nutrient contents,enzyme activities,bacterial community composition as well as C and nitrogen(N)contents of the plant roots.Ecoenzymatic stoichiometric indices were calculated to estimate the relative C,N or P limitations of the microbial community.There was a significant effect of altitude on soil organic C in the rhizosphere,and a turning point in these measured variables was detected at an altitude of 2000 m.At low elevations,the rapid growth of invasive plants depleted the deficient phosphorus(P)in tropical soils,leading to microbial P limitation;at high elevations,microbes invested more energy to obtain C from resistant litter,leading to microbial C limitation.Bacterial beta diversity and soil pH contributed most to the altitudinal differences in ecoenzymatic stoichiometry,and Proteobacteria and Acidobacteria were the dominant bacterial phyla that determined the nutrient uptake status of microorganisms.These results demonstrate how microbial nutrient acquisition belowground of A.adenophora along an altitudinal gradient,which could contribute to further knowledge about the effects of altitude on biological invasion.展开更多
Iron oxides, including α-Fe2O3, γ-Fe2O3, Fe3O4, etc. are one of the most widely investigated materials for their fundamental properties and potential applications. One-dimensional （1-D） iron oxides nanostructures ...Iron oxides, including α-Fe2O3, γ-Fe2O3, Fe3O4, etc. are one of the most widely investigated materials for their fundamental properties and potential applications. One-dimensional （1-D） iron oxides nanostructures are the focus of recent research activi- ties because of their wide applications in magnetic refrigeration, information storage, electronics, catalysts, Li-ion battery, pigment, gas sensors, etc. This review covers the recent progress in the synthesis, properties and applications of 1-D iron oxides nanostructures. The paper begins with the introduction to 1-D iron oxides nanostructures, followed by the typical synthetic methods developed for the synthesis of 1-D iron oxides nanostructures. Then, the typical 1-D iron oxides nanostructures, in- cluding nanowires/nanorods, nanotubes, nanobelts, nanochalns, and special 3-D structures built on 1-D building blocks, are introduced in detail. The properties of 1-D iron oxides nanostructures are then discussed, focusing on the magnetic, gas sensing, and electrochemical and photocatalytic properties. Finally, we draw conclusions and look at the prospects of 1-D iron oxides nanostructures.展开更多
基金supported by Yunnan Fundamental Research Projects(202101AU070150)the National Natural Science Foundation of China(31870524,32071663,32071661).
文摘Tropical mountain ecosystems are usually colonized by numerous invasive plant species and represent an ideal‘natural laboratory’to study the effects of altitude on plant invasion.The aim of this study was to investigate the soil chemical and microbiological properties along an altitudinal gradient on a mountain colonized by the invader Ageratina adenophora.Rhizosphere soil of A.adenophora was collected over an altitudinal gradient(1400–2400 m)in Ailao Shan,China.We determined soil organic carbon(C),nutrient contents,enzyme activities,bacterial community composition as well as C and nitrogen(N)contents of the plant roots.Ecoenzymatic stoichiometric indices were calculated to estimate the relative C,N or P limitations of the microbial community.There was a significant effect of altitude on soil organic C in the rhizosphere,and a turning point in these measured variables was detected at an altitude of 2000 m.At low elevations,the rapid growth of invasive plants depleted the deficient phosphorus(P)in tropical soils,leading to microbial P limitation;at high elevations,microbes invested more energy to obtain C from resistant litter,leading to microbial C limitation.Bacterial beta diversity and soil pH contributed most to the altitudinal differences in ecoenzymatic stoichiometry,and Proteobacteria and Acidobacteria were the dominant bacterial phyla that determined the nutrient uptake status of microorganisms.These results demonstrate how microbial nutrient acquisition belowground of A.adenophora along an altitudinal gradient,which could contribute to further knowledge about the effects of altitude on biological invasion.
基金supported by the National Natural Science Foundation of China (Grant No. 51002059)the National Basic Research Program of China (Grant No. 2011CBA00700)+2 种基金the Natural Science Foundation of Hubei Province (Grant No. 2009CDB326)the Research Fund for the Doctoral Program of Higher Education (Grant Nos. 20090142120059, 20100142120053)the Director Fund of WNLO. Special thanks to the Analysis and Testing Center of HUST
文摘Iron oxides, including α-Fe2O3, γ-Fe2O3, Fe3O4, etc. are one of the most widely investigated materials for their fundamental properties and potential applications. One-dimensional （1-D） iron oxides nanostructures are the focus of recent research activi- ties because of their wide applications in magnetic refrigeration, information storage, electronics, catalysts, Li-ion battery, pigment, gas sensors, etc. This review covers the recent progress in the synthesis, properties and applications of 1-D iron oxides nanostructures. The paper begins with the introduction to 1-D iron oxides nanostructures, followed by the typical synthetic methods developed for the synthesis of 1-D iron oxides nanostructures. Then, the typical 1-D iron oxides nanostructures, in- cluding nanowires/nanorods, nanotubes, nanobelts, nanochalns, and special 3-D structures built on 1-D building blocks, are introduced in detail. The properties of 1-D iron oxides nanostructures are then discussed, focusing on the magnetic, gas sensing, and electrochemical and photocatalytic properties. Finally, we draw conclusions and look at the prospects of 1-D iron oxides nanostructures.
