The composite microbial system of MC1 was used to degrade corn stalk in order to determine properties of the degraded products as well as bacterial composition of MC1. Results indicated that the pH of the fermentation...The composite microbial system of MC1 was used to degrade corn stalk in order to determine properties of the degraded products as well as bacterial composition of MC1. Results indicated that the pH of the fermentation broth was typical of lignocellulose degradation by MC1, decreasing in the early phase and increasing in later stages of the degradation. The microbial biomass peaked on the day 3 after degradation. The MC1 efficiently degraded the corn stalk by nearly 70% during which its cellulose content decreased by 71.2%, hemicellulose by 76.5% and lignin by 24.6%. The content of water-soluble carbohydrates (WSC) in the fermentation broth increased progressively during the first three days, and decreased thereafter, suggesting an accumulation of WSC in the early phase of the degradation process. Total levels of various volatile products peaked in the third day after degradation, and 7 types of volatile products were detected in the fermentation broth. These were ethanol, acetic acid, 1,2-ethanediol, propanoic acid, butanoic acid, 3- methyl-butanoic acid and glycerine. Six major compounds were quantitatively analysed and the contents of each compound were ethanol (0.584 g/L), acetic acid (0.735 g/L), 1,2-ethanediol (0.772 g/L), propanoic acid (0.026 g/L), butanoic acid (0.018 g/L) and glycerine (4.203 g/L). Characterization of bacterial cells collected from the culture solution, based on 16S rDNA PCR-DGGE analysis of DNAs, showed that the composition of bacterial community in MC1 coincided basically with observations from previous studies. This indicated that the structure of MC1 is very stable during degradation of different lignocellulose materials.展开更多
To accelerate the decomposition of wheat straw directly returned to soil, we constructed a microbial system (ADS-3) from agricultural soil containing rotting straw residues using a 40-wk limited cultivation. To asse...To accelerate the decomposition of wheat straw directly returned to soil, we constructed a microbial system (ADS-3) from agricultural soil containing rotting straw residues using a 40-wk limited cultivation. To assess its potential use for accelerating straw decomposing, the decomposing characteristics and the microbial composition of ADS-3 were analyzed. The results indicated that it could degrade wheat straw and filter paper by 63.8 and 80%, respectively, during 15 d of incubation. Straw hemicellulose degraded dramatically 51.2% during the first 3 d, decreasing up to 73.7% by the end of incubation. Cellulose showed sustained degradation reaching 53.3% in 15 d. Peak values of xylanase and cellulase activities appeared at 3 and 11 d, with 1.32 and 0.15 U mL-1, respectively. Estimated pH averaged 6.4-7.6 during the degradation process, which approximated acidity and alkalinity of normal soils. The microbial composition of ADS-3 was stable based on denaturing gradient gel electrophoresis (DGGE) analysis. By using bacterial 16S rRNA and fungal 26S rRNA gene clone library analysis, 20 bacterial clones and 7 fungal clones were detected. Closest identified relatives of bacteria represented by Bacillus fusiformis, Cytophaga sp., uncultured Clostridiales bacterium, Ruminobacillus xylanolyticum, Clostridium hydroxybenzoicum, and uncultured proteobacterium and the fungi were mainly identified as related to Pichia sp. and uncultured fungus.展开更多
Environmental safety issues involved in transgenic plants have become the concern of researchers, practitioners and policy makers in recent years. Potential differences between Bt maize(ND1324 and ND2353 expressing t...Environmental safety issues involved in transgenic plants have become the concern of researchers, practitioners and policy makers in recent years. Potential differences between Bt maize(ND1324 and ND2353 expressing the insecticidal Cry1Ab protein) and near-isogenic non-Bt varieties(ND1392 and ND223) in their influence on the composite microbial system of MC1 during the fermentation process were studied during 2011-2012. Cry1Ab protein in Bt maize residues didn't affect characteristics of lignocellulose degradation by MC1, pH of fermentation broth decreasing at initial stage and increasing at later stage of degradation. The quality of various volatile products in fermentation broth showed that no signifi cant difference of residues fermentation existed between Bt maize and non-Bt maize. During the fermentation MC1 efficiently degraded maize residues by 83%-88%, and cellulose, hemicelluloses and lignin content decreased by 70%-72%, 72%-75% and 30%-37%, respectively. Besides that, no consistent difference was found between Bt and non-Bt maize residues lignocellulose degradation by MC1 during the fermentation process. MC1 degraded 88%-89% Cry1Ab protein in Bt maize residues, and in the fermentation broth of MC1 and bacteria of MC1 Cry1Ab protein was not detected. DGGE profi le analyses revealed that the microbial community drastically changed during 1-3 days and became stable until the 9th day. Though the dominant strains at different fermentation stages had signifi cantly changed, no difference on the dominant strains was observed between Bt and non-Bt maize at different stages. Our study indicated that Cry1Ab protein did not infl uence the growth characteristic of MC1.展开更多
Bidens pilosa is recognized as one of the major invasive plants in China.Its invasion has been associated with significant losses in agriculture,forestry,husbandry,and biodiversity.Soil ecosystems play an important ro...Bidens pilosa is recognized as one of the major invasive plants in China.Its invasion has been associated with significant losses in agriculture,forestry,husbandry,and biodiversity.Soil ecosystems play an important role in alien plant invasion.Microorganisms within the soil act as intermediaries between plants and soil ecological functions,playing a role in regulating soil enzyme activities and nutrient dynamics.Understanding the interactions between invasive plants,soil microorganisms,and soil ecological processes is vital for managing and mitigating the impacts of invasive species on the environment.In this study,we conducted a systematic analysis focusing on B.pilosa and Setaria viridis,a common native companion plant in the invaded area.To simulate the invasion process of B.pilosa,we constructed homogeneous plots consisting of B.pilosa and S.viridis grown separately as monocultures,as well as in mixtures.The rhizosphere and bulk soils were collected from the alien plant B.pilosa and the native plant S.viridis.In order to focus on the soil ecological functional mechanisms that contribute to the successful invasion of B.pilosa,we analyzed the effects of B.pilosa on the composition of soil microbial communities and soil ecological functions.The results showed that the biomass of B.pilosa increased by 27.51% and that of S.viridis was significantly reduced by 66.56%.The organic matter contents in the bulk and rhizosphere soils of B.pilosa were approximately 1.30 times those in the native plant soils.The TN and NO_(3)^(-)contents in the rhizosphere soil of B.pilosa were 1.30 to 2.71 times those in the native plant soils.The activities of acid phosphatase,alkaline phosphatase,and urease in the rhizosphere soil of B.pilosa were 1.98-2.25 times higher than in the native plant soils.Using high-throughput sequencing of the16S rRNA gene,we found that B.pilosa altered the composition of the soil microbial community.Specifically,many genera in Actinobacteria and Proteobacteria were enriched in B.pilosa soils.Further correlation analyses verified that these genera had significantly positive relationships with soil nutrients and enzyme activities.Plant biomass,soil p H,and the contents of organic matter,TN,NO_(3)^(-),TP,AP,TK,and AK were the main factors affecting soil microbial communities.This study showed that the invasion of B.pilosa led to significant alterations in the composition of the soil microbial communities.These changes were closely linked to modifications in plant traits as well as soil physical and chemical properties.Some microbial species related to C,N and P cycling were enriched in the soil invaded by B.pilosa.These findings provide additional support for the hypothesis of soil-microbe feedback in the successful invasion of alien plants.They also offer insights into the ecological mechanism by which soil microbes contribute to the successful invasion of B.pilosa.Overall,our research contributes to a better understanding of the complex interactions between invasive plants,soil microbial communities,and ecosystem dynamics.展开更多
To explore the influence of microbial agems on the decomposition of aging dunnage of the fermentation bed, this paper took the aging dunnage as the raw materials, obtained microbial strains of different types through ...To explore the influence of microbial agems on the decomposition of aging dunnage of the fermentation bed, this paper took the aging dunnage as the raw materials, obtained microbial strains of different types through isolation and purification, chose dominant groups to make compound microbial agents, and adopted composting decomposition experiment. The results showed that Bacillus subtilis of different ratios was added, Trichoderma koningii and Thermo actinomycetaceac could promote the decomposition of aging dunnage, especially composite microbial agents (Kc:Kn:Gf = 1:1:1 ) had the best effect of decomposition, the high tem- perature was kept for 13 days. In the end of composting, degradation rate of cellulose, degradation rate of lignin, GI, and C/N were 47.6%, 30. 2%, 98.5%, and 18.5%. Bacillus coli was not detected.展开更多
Conservation tillage as an effective alternative to mitigate soil degradation has attracted worldwide attention,but the influences of conservation tillage on soil microbial community and especially function remain unc...Conservation tillage as an effective alternative to mitigate soil degradation has attracted worldwide attention,but the influences of conservation tillage on soil microbial community and especially function remain unclear.Shotgun metagenomics sequencing was performed to examine the taxonomic and functional community variations of black soils under three tillage regimes,namely no-tillage with residue(maize straw)return(NTS),moldboard plow with residue return(MPS),and moldboard plow without residue return(MPN)in Northeast China.The results revealed:1)Soil bacterial and archaeal communities differed significantly under different tillage regimes in contrast to soil fungal community.2)The overlay of less tillage and residues return under NTS led to unique soil microbial community composition and functional composition.Specifically,in contrast to other treatments,NTS increased the relative abundances of some taxa such as Bradyrhizobium,Candidatus Solibacter,and Reyranella,along with the relative abundances of some taxa such as Sphingomonas,Unclassified Chloroflexi and Nitrososphaera decreased;NTS had a unique advantage of increasing the relative abundances of genes involved in‘ATP-binding cassette(ABC)transporters’and‘quorum sensing(QS)’pathways,while MPN favored the genes involved in‘flagellar assembly’pathway and some metabolic pathways such as‘carbon’and‘glyoxylate and dicarboxylate’and‘selenocompound’metabolisms.3)Significantly different soil bacterial phyla(Acidobacteria,Gemmatimonadetes,and Chloroflexi)and metabolic pathways existed between MPN and another two treatments(NTS and MPS),while did not exist between NTS and MPS.4)Dissolved organic carbon(DOC)and soil bulk density were significantly affected(P<0.05)by tillage and accounted for the variance both in microbial(bacterial)community structure and functional composition.These results indicated that a change in tillage regime from conventional to conservation tillage results in a shift of microbial community and functional genes,and we inferred that residue return played a more prominent role than less tillage in functional shifts in the microbial community of black soils.展开更多
Partial substitution of inorganic fertilizers with organic amendments is an important agricultural management practice.An 11-year field experiment(22 cropping periods)was carried out to analyze the impacts of differen...Partial substitution of inorganic fertilizers with organic amendments is an important agricultural management practice.An 11-year field experiment(22 cropping periods)was carried out to analyze the impacts of different partial substitution treatments on crop yields and the transformation of nitrogen fractions in greenhouse vegetable soil.Four treatments with equal N,P_(2)O_(5),and K_(2)O inputs were selected,including complete inorganic fertilizer N(CN),50%inorganic fertilizer N plus 50%pig manure N(CPN),50%inorganic fertilizer N plus 25%pig manure N and 25%corn straw N(CPSN),and 50%inorganic fertilizer N plus 50%corn straw N(CSN).Organic substitution treatments tended to increase crop yields since the 6th cropping period compared to the CN treatment.From the 8th to the 22nd cropping periods,the highest yields were observed in the CPSN treatment where yields were 7.5-11.1%greater than in CN treatment.After 11-year fertilization,compared to CN,organic substitution treatments significantly increased the concentrations of NO_(3)^(-)-N,NH_(4)^(+)-N,acid hydrolysis ammonium-N(AHAN),amino acid-N(AAN),amino sugar-N(ASN),and acid hydrolysis unknown-N(AHUN)in soil by 45.0-69.4,32.8-58.1,49.3-66.6,62.0-69.5,34.5-100.3,and 109.2-172.9%,respectively.Redundancy analysis indicated that soil C/N and OC concentration significantly affected the distribution of N fractions.The highest concentrations of NO_(3)^(-)-N,AHAN,AAN,AHUN were found in the CPSN treatment.Organic substitution treatments increased the activities ofβ-glucosidase,β-cellobiosidase,N-acetyl-glucosamidase,L-aminopeptidase,and phosphatase in the soil.Organic substitution treatments reduced vector length and increased vector angle,indicating alleviation of constraints of C and N on soil microorganisms.Organic substitution treatments increased the total concentrations of phospholipid fatty acids(PLFAs)in the soil by 109.9-205.3%,and increased the relative abundance of G^(+)bacteria and fungi taxa,but decreased the relative abundance of G-bacteria,total bacteria,and actinomycetes.Overall,long-term organic substitution management increased soil OC concentration,C/N,and the microbial population,the latter in turn positively influenced soil enzyme activity.Enhanced microorganism numbers and enzyme activity enhanced soil N sequestration by transforming inorganic N to acid hydrolysis-N(AHN),and enhanced soil N supply capacity by activating non-acid hydrolysis-N(NAHN)to AHN,thus improving vegetable yield.Application of inorganic fertilizer,manure,and straw was a more effective fertilization model for achieving sustainable greenhouse vegetable production than application of inorganic fertilizer alone.展开更多
Greenhouse vegetable production has been characterized by high agricultural inputs, high temperatures, and high cropping indexes. As an intensive form of agriculture, nutrient cycling induced by microbial activities i...Greenhouse vegetable production has been characterized by high agricultural inputs, high temperatures, and high cropping indexes. As an intensive form of agriculture, nutrient cycling induced by microbial activities in the greenhouses is relatively different from open fields in the same region. However, the responses of soil microbial biomass carbon (MBC) and nitrogen (MBN), enzyme activities, microbial community composition, and yield to organic amendment are not well understood. Therefore, a 5-year greenhouse tomato (Solanum lycopersicum Mill.)-cucumber (Cucumis sativus L.) rotation experiment was conducted. The field experiment comprised 5 treatments: 4/4CN (CN, nitrogen in chemical fertilizer), 3/4CN+1/4MN (MN, nitrogen in pig manure), 2/4CN+2/4MN, 2/4CN+1/4 MN+1/4 SN (SN, nitrogen in corn straw) and 2/4CN+2/4SN. The amounts of nitrogen (N), phosphorus (P2O5), and potassium (K2O) were equal in the five treatments. Starting with the fourth growing season, the optimal yield was obtained from soil treated with straw. MBC, MBN, phospholipid fatty acid (PLFA) profiles, and enzyme activities were significantly changed by 5 years of substitution with organic amendments. Redundancy analysis showed that MBC accounts for 89.5 and 52.3% of the total enzyme activity and total community variability, respectively. The activities of phosphomonoesterase, N-acetyl-glucosaminidase, and urease, and the relative abundances of fungi, actinomycetes, and Gram-negative bacteria were significantly and positively related to vegetable yields. Considering the effects of organic amendments on soil microbial characteristics and vegetable yield, 2/4CN+1/4MN+1/4SN can improve soil quality and maintain sustainable high yield in greenhouse vegetable production.展开更多
Soil erosion is a serious issue in the sandy-hilly region of Shanxi Province,Northwest China.There has been gradual improvement due to vegetation restoration,but soil microbial community characteristics in different v...Soil erosion is a serious issue in the sandy-hilly region of Shanxi Province,Northwest China.There has been gradual improvement due to vegetation restoration,but soil microbial community characteristics in different vegetation plantation types have not been widely investigated.To address this,we analyzed soil bacterial and fungal community structures,diversity,and microbial and soil environmental factors in Caragana korshinskii Kom.,Populus tomentosa Carr.,Populus simonii Carr.,Salix matsudana Koidz,and Pinus tabulaeformis Carr.forests.There were no significant differences in the dominant bacterial community compositions among the five forest types.The alpha diversity of the bacteria and fungi communities showed that ACE(abundance-based coverage estimator),Chao1,and Shannon indices in C.korshinskii forest were significantly higher than those in the other four forest types(P<0.05).Soil organic matter,total nitrogen,and urease had a greater impact on bacterial community composition,while total nitrogen,β-glucosidase,and urease had a greater impact on fungal community composition.The relative abundance of beneficial and pathogenic microorganisms was similar across all forest types.Based on microbial community composition,diversity,and soil fertility,we ranked the plantations from most to least suitable as follows:C.korshinskii,S.matsudana,P.tabulaeformis,P.tomentosa,and P.simonii.展开更多
Dust fallout can have diverse impacts ranging from major health problems to environmental concerns. It can harbour disease-causing microorganisms and toxic heavy metals, and it is therefore critical to establish the m...Dust fallout can have diverse impacts ranging from major health problems to environmental concerns. It can harbour disease-causing microorganisms and toxic heavy metals, and it is therefore critical to establish the microbial and the mineral compositions of the dust fallout in a particular site and elucidate the possible related health implications for humans and the entire environment. In this study, dust fallout samples were collected from Arandis, a town in the Erongo region (Namibia), using the American Society for Testing and Materials standard method (ASTM D1739) for collection and analysis of dust fallout (settleable particulate matter). The identification of present viable bacteria was done through culturing and isolation techniques and the morphological characteristics, and the elemental composition of the dust fallout were determined using the Stereomicroscope and the X-ray fluorescence, respectively. The results showed that the most dominant bacteria contained in the fallout dust were the Bacillus species. The morphological characterisation revealed that the present particles were mixed black, brownish, greenish, and crystal particles with irregular, cubical, flocks and flake shapes. The elemental investigations indicated that the dust fallout contained Hg, As, Fe, Ni, Cr, Mn, Al and Pb occurring in varying concentrations and the status of pollution of the dust fallout ranged from low to severe concerning the inconsistent heavy metal indices that are the contamination factor, pollution load index and the enrichment factor.展开更多
Background:Nitrogen(N)and phosphorus(P)deposition have largely affected soil respiration(Rs)in forest ecosystems.However,few studies have explored how N and P individually or in combination to influence Rs and its com...Background:Nitrogen(N)and phosphorus(P)deposition have largely affected soil respiration(Rs)in forest ecosystems.However,few studies have explored how N and P individually or in combination to influence Rs and its components(autotrophic respiration,Ra;heterotrophic respiration,Rh),especially in highly P-limited subtropical forests.To address this question,we conducted a field manipulation experiment with N and/or P addition in a 50-year-old subtropical secondary forest.Results:We found that N addition on average reduced Rs,Ra,and Rh by 15.2%,15%,and 11.7%,respectively during 2-year field study.P addition had an inconsistent effect on Ra,with Ra increasing by 50.5%in the first year but reducing by 26.6%in the second year.Moreover,P addition on average decreased Rh by 8.9%–30.9%and Rs by 6.7%–15.6%across 2 years.In contrast,N and P co-addition on average increased Rs,Ra,and Rh by 1.9%,7.9%,and 2.1%during the experimental period.Though Rs and Rh were significantly correlated with soil temperature,their temperature sensitivities were not significantly changed by fertilization.Ra was predominantly regulated by soil nitrogen availability(NH4+and NO3−),soil dissolved organic carbon(DOC),and enzyme activities,while the variation in Rh was mainly attributable to changes in soil microbial community composition and soilβ-D-Cellubiosidase(CB)andβ-Xylosidase(XYL)activities.Conclusion:Our findings highlight the contrasting responses of Rs and its components to N or P addition against N and P co-addition,which should be differentially considered in biogeochemical models in order to improve prediction of forest carbon dynamics in the context of N and P enrichment in terrestrial ecosystems.展开更多
The Loess Plateau,located in Gansu Province,is an important energy base in China because most of the oil and gas resources are distributed in Gansu Province.In the last 40 a,ecological environment in this region has b...The Loess Plateau,located in Gansu Province,is an important energy base in China because most of the oil and gas resources are distributed in Gansu Province.In the last 40 a,ecological environment in this region has been extremely destroyed due to the over-exploitation of crude-oil resources.Remediation of crude-oil contaminated soil in this area remains to be a challenging task.In this study,in order to elucidate the effects of organic compost and biochar on phytoremediation of crude-oil contaminated soil(20 g/kg)by Calendula officinalis,we designed five treatments,i.e.,natural attenuation(CK),planted C.officinalis only(P),planted C.officinalis with biochar amendment(PB),planted C.officinalis with organic compost amendment(PC),and planted C.officinalis with co-amendment of biochar and organic compost(PBC).After 152 d of cultivation,total petroleum hydrocarbons(TPH)removal rates of CK,P,PB,PC and PBC were 6.36%,50.08%,39.58%,73.10%and 59.87%,respectively.Shoot and root dry weights of C.officinalis significantly increased by 172.31%and 80.96%under PC and 311.61%and 145.43%under PBC,respectively as compared with P(P<0.05).Total chlorophyll contents in leaves of C.officinalis under P,PC and PBC significantly increased by 77.36%,125.50%and 79.80%,respectively(P<0.05)as compared with PB.Physical-chemical characteristics and enzymatic activity of soil in different treatments were also assessed.The highest total N,total P,available N,available P and SOM(soil organic matter)occurred in PC,followed by PBC(P<0.05).C.officinalis rhizospheric soil dehydrogenase(DHA)and polyphenol oxidase(PPO)activities in PB were lower than those of other treatments(P<0.05).The values of ACE(abundance-based coverage estimators)and Chao 1 indices for rhizospheric bacteria were the highest under PC followed by PBC,P,PB and CK(P<0.05).However,the Shannon index for bacteria was the highest under PC and PBC,followed by P,PB and CK(P<0.05).In terms of soil microbial community composition,Proteiniphilum,Immundisolibacteraceae and Solimonadaceae were relatively more abundant under PC and PBC.Relative abundances of Pseudallescheria,Ochroconis,Fusarium,Sarocladium,Podospora,Apodus,Pyrenochaetopsis and Schizothecium under PC and PBC were higher,while relative abundances of Gliomastix,Aspergillus and Alternaria were lower under PC and PBC.As per the nonmetric multidimensional scaling(NMDS)analysis,application of organic compost significantly promoted soil N and P contents,shoot length,root vitality,chlorophyll ratio,total chlorophyll,abundance and diversity of rhizospheric soil microbial community in C.officinalis.A high p H value and lower soil N and P contents induced by biochar,altered C.officinalis rhizospheric soil microbial community composition,which might have restrained its phytoremediation efficiency.The results suggest that organic compost-assisted C.officinalis phytoremediation for crude-oil contaminated soil was highly effective in the Loess Plateau,China.展开更多
Litter microorganisms play a crucial role in the biological decomposition in forest ecosystems;however,the coupling effect of meteorological and substrate changes on it during the different stages of leaf decompositio...Litter microorganisms play a crucial role in the biological decomposition in forest ecosystems;however,the coupling effect of meteorological and substrate changes on it during the different stages of leaf decomposition in situ remains unclear.Hence,according to meteorological factors dynamics,a one-year field litter of Quercus wutaishanica in situ decomposition experiment was designed for four decay stages in a warm temperate forest.Microbial community composition was characterized using Illumina sequencing of fungal ITS and bacterial 16S genes.Bacterial(6.6)and fungal(3.6)Shannon indexes were the largest after 125 days’litter decomposition(October).The relative abundance of Acidobacteria after 342 days and Bacteroidetes after 125 days were 3 and 24 times higher than after 31 days,respectively.Some non-dominant species(bacteria:Firmicutes,Planctomycotes,and Verrucomicrobia;fungi:Chytridiomycota and Glomeromomycota)may be absent or present at different decomposition stages due to litter properties or meteorological factors.Chemoheterotrophy and aerobic-chemoheterotrophy were the dominant bacterial functional groups,and the dominant fungal functional groups were saprotrophs,pathotrophs,and symbiotrophs.Precipitation and relative humidity significantly affected bacteria.Temperature,sunlight intensity,and net radiation significantly affected fungi.Besides,among the relative contributions of changes in bacterial and fungal community structure,leaf litter properties alone explained the variation of 5.51%and 10.63%.Microbial diversity and decay stage directly affected the litter mass-loss rate,with meteorological factors(precipitation,relative humidity,air temperature,and sunlight intensity)being indirect.Our findings highlight the importance of microbial diversity for leaf litter decomposition and the influence of meteorological factors.展开更多
As widespread wetland plants,Phragmites play a vital role in water purification and are widely utilized in constructed wetlands(accounting for 15.5%of applied wetland plants)as a natural alternative to wastewater trea...As widespread wetland plants,Phragmites play a vital role in water purification and are widely utilized in constructed wetlands(accounting for 15.5%of applied wetland plants)as a natural alternative to wastewater treatment.However,despite such common applications,current understanding of the basic composition of the Phragmites root-inhabiting microbiome and the complex functions of each member of this microbiome remains incomplete,especially regarding pollution remediation.This review summa-rizes the advances that have been made in ecological and biochemical research on the Phragmites root microbiome,including bacteria,archaea,and fungi.Based on next-generation sequencing,microbial com-munity compositions have been profiled under various environmental conditions.Furthermore,culture-based methods have helped to clarify the functions of the microbiome,such as metal iron stabilization,organic matter degradation,and nutrient element transformation.The unique community structure and functions are highly impacted by Phragmites lineages and environmental factors such as salinity.Based on the current understanding of the Phragmites root microbiome,we propose that synthetic microbial com-munities and iron–manganese plaque could be applied and intensified in constructed wetlands to help promote their water purification performance.展开更多
During the past two decades interest in linking soil microbial community composition and activity with ecosystem scale field studies of nutrient cycling or plant community response to disturbances has grown.Despite it...During the past two decades interest in linking soil microbial community composition and activity with ecosystem scale field studies of nutrient cycling or plant community response to disturbances has grown.Despite its importance there are challenges in making this linkage.Foremost is the question of analytical feasibility.In general,microbiological community-level methodologies have not been readily adaptable to the large sample sizes necessary for ecosystem-scale research.As a result,it has been difficult to generate compatible microbial and ecosystem data sets.Soil lipid analysis shows potential as a middle ground between simple biomass measures and molecular profiling.However,the two protocols that have most often been followed are either rapid but indiscriminate(total lipid analysis or fatty acid methyl ester analysis;FAME),or precise but time consuming(phospholipid fatty acid analysis;PLFA).In this paper we report results from a standardized soil used test a modified extraction method(the‘hybrid’method)developed to balance the speed of FAME and the precision of PLFA in order to increase sample throughput.In comparing the three methods,we find that FAME and PLFA are qualitatively and quantitatively distinct.The FAME method yielded the highest fatty acid abundance,but also had high variance resulting in low precision.The PLFA method had precision,but low yield.The‘hybrid’method fell midway between FAME and PLFA for quantitative fatty acid yield.In addition,the hybrid extraction can be completed in a fraction of the time it takes for PLFA.The hybrid protocol appears to provide an optimal balance between effort and accuracy and therefore is a good choice for large-scale ecosystem studies.展开更多
There is limited knowledge about microbial communities and their ecological functions in karst caves with high CO_(2)concentrations.Here,we studied the microbial community compositions and functions in Shuiming Cave( ...There is limited knowledge about microbial communities and their ecological functions in karst caves with high CO_(2)concentrations.Here,we studied the microbial community compositions and functions in Shuiming Cave( "SMC",CO_(2)concentration 3 303 ppm) and Xueyu Cave( "XYC",CO_(2)concentration 8 753 ppm) using Illumina MiSeq high-throughput sequencing in combination with BIOLOG test.The results showed that Proteobacteria,Actinobacteria and Bacteroidetes were dominant phyla in these two caves,and Thaumarchaeota was the most abundant in the rock wall samples of SMC.The microbial diversity in the water samples decreased with increasing HCO_(3)^(-)concentration,and it was higher in XYC than that in SMC.The microbial community structures in the sediment and rock wall samples were quite different between the two caves.High concentrations of CO_(2)can reduce the microbial diversity on the rock walls in karst caves,probably through changing microbial preference for different types of carbon sources and decreasing the microbial utilization rate of carbon sources.These results expanded our understanding of microbial community and its response to environments in karst caves with high CO_(2).展开更多
Aims Better understanding of microbial compositional and physiological acclimation mechanisms is critical for predicting terrestrial ecosystem responses to global change.The aim is to assess variations in soil microbi...Aims Better understanding of microbial compositional and physiological acclimation mechanisms is critical for predicting terrestrial ecosystem responses to global change.The aim is to assess variations in soil microbial communities under future scenarios of changing precipitation and N deposition in a semiarid grassland of northern China.Methods In order to explicitly estimate microbial responses,a field experiment with water and N addition was established in April 2005 and continuously conducted for 4 years.Specifically,soil microbial community composition and microbial C utilization potential were determined by phospholipid fatty acid(PLFA)and community-level physiological profiles,respectively.Important Findings Water addition had no effects on the PLFA concentrations of grampositive(GP)and negative bacteria(GN),total bacteria and fungi.However,N addition caused significant reductions in the PLFA concentrations of GP,GN,total bacteria and fungi and thus decreased total PLFA of microbial communities.Moreover,there were interactive effects of water and N addition on GN/GPand the ratio of fungal to bacterial PLFA(F/B).In addition,synergistic effects were found between water and nitrogen in affecting microbial C utilization potentials,which implies that microbial C utilization potentials tend to be enhanced when both N and water availability are sufficient.Overall,the microbial responses to water and N addition support our hypothesis that water and N addition may be combined together to affect microbial communities in the semiarid grassland.展开更多
Background:Freeze–thaw events are common in boreal and temperate forest ecosystems and are increasingly infuenced by climate warming.Soil microorganisms play an important role in maintaining ecosystem stability,but t...Background:Freeze–thaw events are common in boreal and temperate forest ecosystems and are increasingly infuenced by climate warming.Soil microorganisms play an important role in maintaining ecosystem stability,but their responses to freeze–thaw cycles(FTCs)are poorly understood.We conducted a feld freeze–thaw experiment in a natural Korean pine and broadleaf mixed forest in the Changbai Mountain Nature Reserve,China,to determine the dynamic responses of soil microbial communities to FTCs.Results:Bacteria were more sensitive than fungi to FTCs.Fungal biomass,diversity and community composition were not signifcantly afected by freeze–thaw regardless of the stage.Moderate initial freeze–thaw resulted in increased bacterial biomass,diversity,and copiotrophic taxa abundance.Subsequent FTCs reduced the bacterial biomass and diversity.Compared with the initial FTC,subsequent FTCs exerted an opposite efect on the direction of change in the composition and function of the bacterial community.Soil water content,dissolved organic carbon,ammonium nitrogen,and total dissolved phosphorus were important factors determining bacterial community diversity and composition during FTCs.Moreover,the functional potentials of the microbial community involved in C and N cycling were also afected by FTCs.Conclusions:Diferent stages of FTCs have diferent ecological efects on the soil environment and microbial activities.Soil FTCs changed the soil nutrients and water availability and then mainly infuenced bacterial community composition,diversity,and functional potentials,which may disturb C and N states in this temperate forest soil.This study also improves our understanding of microbial communities regulating their ecological functions in response to climate change.展开更多
The impact of forest microhabitats on physiochemical properties of the soil and that of microbial communities on tropical soils remain poorly understood.To elucidate the effect of tropical forest stand on leaf litter ...The impact of forest microhabitats on physiochemical properties of the soil and that of microbial communities on tropical soils remain poorly understood.To elucidate the effect of tropical forest stand on leaf litter and soil microbial communities,we studied enzyme activities,microbial biomass,and diversity in three distinct microhabitats in terms of plant richness,diameter at breast height(DBH),and physiochemical properties of soil and litter,each associated with a different Vanilla sp.In the soil,positive correlations were found between electrical conductivity(EC)and total organic carbon(TOC)with phosphatase activity,and between nitrogen(N)and water-soluble carbon(WSC)content with urease activity(UA).In the litter,the water content was positively correlated with bacterial and fungal biomass,and N and WSC contents were positively correlated with fungal biomass.Positive correlations were found between plant richness and UA in the soil,plant richness and fungal biomass in the soil and litter,and DBH and fungal biomass in the litter.Amplicon sequencing revealed differences between microhabitats in the relative abundance of some fungal and bacterial taxa and in the bacterial community composition of both litter and soil.Bacterial richness and diversity were different between microhabitats,and,in litter samples,they were negatively correlated with DBH and plant richness,respectively.By contrast,none of the soil and litter physiochemical properties were significantly correlated with microbial diversity.Our results show that significant shifts in enzyme activity,microbial biomass,and diversity in the microhabitats were driven by key abiotic and biotic factors depending on the soil or litter sample type.展开更多
Numerous studies have evaluated the toxicity and endocrine disrupting properties of organic UV filters for aquatic organisms,but little is known about their biodegradation in river sediments and their impact on microo...Numerous studies have evaluated the toxicity and endocrine disrupting properties of organic UV filters for aquatic organisms,but little is known about their biodegradation in river sediments and their impact on microorganisms.We have set up the sterile and microbiological systems in the laboratory,adding 2-ethylhexyl-4-methoxycinnamate(EHMC),one of organic UV filters included in the list of high yield chemicals,at concentrations of 2,20 and 200μg/L,and characterized the microbial community composition and diversity in sediments.Monitoring of EHMC degradation within 30 days revealed that the half-life in the microbial system(3.49 days)was much shorter than that in the sterile system(7.55 days).Two potential degradation products,4-mercaptobenzoic acid and 3-methoxyphenol were identified in the microbial system.Furthermore,high-throughput 16s and 18s rRNA gene sequencing showed that Proteobacteria dominated the sediment bacterial assemblages followed by Chloroflexi,Acidobacteria,Bacteroidetes and Nitrospirae;Eukaryota_uncultured fungus dominated the sediment fungal assemblages.Correlation analysis demonstrated that two bacterium genera(Anaerolineaceae_uncultured and Burkholderiaceae_uncultured)were significantly correlated with the biodegradation of EHMC.These results illustrate the biodegradability of EHMC in river sediments and its potential impact on microbial communities,which can provide useful information for eliminating the pollution of organic UV filters in natural river systems and assessing their potential ecological risks.展开更多
基金This work was supported by the National Natural Science Foundation of China(No.30571088)the National Key Technology Research and Development Program of China during the 11th Five-Year Plan Period(No.2006BAD07A01,2006BAD25B04).
文摘The composite microbial system of MC1 was used to degrade corn stalk in order to determine properties of the degraded products as well as bacterial composition of MC1. Results indicated that the pH of the fermentation broth was typical of lignocellulose degradation by MC1, decreasing in the early phase and increasing in later stages of the degradation. The microbial biomass peaked on the day 3 after degradation. The MC1 efficiently degraded the corn stalk by nearly 70% during which its cellulose content decreased by 71.2%, hemicellulose by 76.5% and lignin by 24.6%. The content of water-soluble carbohydrates (WSC) in the fermentation broth increased progressively during the first three days, and decreased thereafter, suggesting an accumulation of WSC in the early phase of the degradation process. Total levels of various volatile products peaked in the third day after degradation, and 7 types of volatile products were detected in the fermentation broth. These were ethanol, acetic acid, 1,2-ethanediol, propanoic acid, butanoic acid, 3- methyl-butanoic acid and glycerine. Six major compounds were quantitatively analysed and the contents of each compound were ethanol (0.584 g/L), acetic acid (0.735 g/L), 1,2-ethanediol (0.772 g/L), propanoic acid (0.026 g/L), butanoic acid (0.018 g/L) and glycerine (4.203 g/L). Characterization of bacterial cells collected from the culture solution, based on 16S rDNA PCR-DGGE analysis of DNAs, showed that the composition of bacterial community in MC1 coincided basically with observations from previous studies. This indicated that the structure of MC1 is very stable during degradation of different lignocellulose materials.
基金supported by the National Key Technology R&D Program of China (2008BADC4B01 and 2008BADC4B17)the National Special Research Fund for Non-Profit Sector, China (200803033)
文摘To accelerate the decomposition of wheat straw directly returned to soil, we constructed a microbial system (ADS-3) from agricultural soil containing rotting straw residues using a 40-wk limited cultivation. To assess its potential use for accelerating straw decomposing, the decomposing characteristics and the microbial composition of ADS-3 were analyzed. The results indicated that it could degrade wheat straw and filter paper by 63.8 and 80%, respectively, during 15 d of incubation. Straw hemicellulose degraded dramatically 51.2% during the first 3 d, decreasing up to 73.7% by the end of incubation. Cellulose showed sustained degradation reaching 53.3% in 15 d. Peak values of xylanase and cellulase activities appeared at 3 and 11 d, with 1.32 and 0.15 U mL-1, respectively. Estimated pH averaged 6.4-7.6 during the degradation process, which approximated acidity and alkalinity of normal soils. The microbial composition of ADS-3 was stable based on denaturing gradient gel electrophoresis (DGGE) analysis. By using bacterial 16S rRNA and fungal 26S rRNA gene clone library analysis, 20 bacterial clones and 7 fungal clones were detected. Closest identified relatives of bacteria represented by Bacillus fusiformis, Cytophaga sp., uncultured Clostridiales bacterium, Ruminobacillus xylanolyticum, Clostridium hydroxybenzoicum, and uncultured proteobacterium and the fungi were mainly identified as related to Pichia sp. and uncultured fungus.
文摘Environmental safety issues involved in transgenic plants have become the concern of researchers, practitioners and policy makers in recent years. Potential differences between Bt maize(ND1324 and ND2353 expressing the insecticidal Cry1Ab protein) and near-isogenic non-Bt varieties(ND1392 and ND223) in their influence on the composite microbial system of MC1 during the fermentation process were studied during 2011-2012. Cry1Ab protein in Bt maize residues didn't affect characteristics of lignocellulose degradation by MC1, pH of fermentation broth decreasing at initial stage and increasing at later stage of degradation. The quality of various volatile products in fermentation broth showed that no signifi cant difference of residues fermentation existed between Bt maize and non-Bt maize. During the fermentation MC1 efficiently degraded maize residues by 83%-88%, and cellulose, hemicelluloses and lignin content decreased by 70%-72%, 72%-75% and 30%-37%, respectively. Besides that, no consistent difference was found between Bt and non-Bt maize residues lignocellulose degradation by MC1 during the fermentation process. MC1 degraded 88%-89% Cry1Ab protein in Bt maize residues, and in the fermentation broth of MC1 and bacteria of MC1 Cry1Ab protein was not detected. DGGE profi le analyses revealed that the microbial community drastically changed during 1-3 days and became stable until the 9th day. Though the dominant strains at different fermentation stages had signifi cantly changed, no difference on the dominant strains was observed between Bt and non-Bt maize at different stages. Our study indicated that Cry1Ab protein did not infl uence the growth characteristic of MC1.
基金funded by the National Key R&D Program of China(2022YFC2601100,2021YFD1400100 and 2021YFC2600400)the National Natural Science Foundation of China(42207162)。
文摘Bidens pilosa is recognized as one of the major invasive plants in China.Its invasion has been associated with significant losses in agriculture,forestry,husbandry,and biodiversity.Soil ecosystems play an important role in alien plant invasion.Microorganisms within the soil act as intermediaries between plants and soil ecological functions,playing a role in regulating soil enzyme activities and nutrient dynamics.Understanding the interactions between invasive plants,soil microorganisms,and soil ecological processes is vital for managing and mitigating the impacts of invasive species on the environment.In this study,we conducted a systematic analysis focusing on B.pilosa and Setaria viridis,a common native companion plant in the invaded area.To simulate the invasion process of B.pilosa,we constructed homogeneous plots consisting of B.pilosa and S.viridis grown separately as monocultures,as well as in mixtures.The rhizosphere and bulk soils were collected from the alien plant B.pilosa and the native plant S.viridis.In order to focus on the soil ecological functional mechanisms that contribute to the successful invasion of B.pilosa,we analyzed the effects of B.pilosa on the composition of soil microbial communities and soil ecological functions.The results showed that the biomass of B.pilosa increased by 27.51% and that of S.viridis was significantly reduced by 66.56%.The organic matter contents in the bulk and rhizosphere soils of B.pilosa were approximately 1.30 times those in the native plant soils.The TN and NO_(3)^(-)contents in the rhizosphere soil of B.pilosa were 1.30 to 2.71 times those in the native plant soils.The activities of acid phosphatase,alkaline phosphatase,and urease in the rhizosphere soil of B.pilosa were 1.98-2.25 times higher than in the native plant soils.Using high-throughput sequencing of the16S rRNA gene,we found that B.pilosa altered the composition of the soil microbial community.Specifically,many genera in Actinobacteria and Proteobacteria were enriched in B.pilosa soils.Further correlation analyses verified that these genera had significantly positive relationships with soil nutrients and enzyme activities.Plant biomass,soil p H,and the contents of organic matter,TN,NO_(3)^(-),TP,AP,TK,and AK were the main factors affecting soil microbial communities.This study showed that the invasion of B.pilosa led to significant alterations in the composition of the soil microbial communities.These changes were closely linked to modifications in plant traits as well as soil physical and chemical properties.Some microbial species related to C,N and P cycling were enriched in the soil invaded by B.pilosa.These findings provide additional support for the hypothesis of soil-microbe feedback in the successful invasion of alien plants.They also offer insights into the ecological mechanism by which soil microbes contribute to the successful invasion of B.pilosa.Overall,our research contributes to a better understanding of the complex interactions between invasive plants,soil microbial communities,and ecosystem dynamics.
基金Sponsored by Hunan Provincial Pig Industry Technology SystemHunan Provincial Program of Agricultural Science and Technology(2012-193)
文摘To explore the influence of microbial agems on the decomposition of aging dunnage of the fermentation bed, this paper took the aging dunnage as the raw materials, obtained microbial strains of different types through isolation and purification, chose dominant groups to make compound microbial agents, and adopted composting decomposition experiment. The results showed that Bacillus subtilis of different ratios was added, Trichoderma koningii and Thermo actinomycetaceac could promote the decomposition of aging dunnage, especially composite microbial agents (Kc:Kn:Gf = 1:1:1 ) had the best effect of decomposition, the high tem- perature was kept for 13 days. In the end of composting, degradation rate of cellulose, degradation rate of lignin, GI, and C/N were 47.6%, 30. 2%, 98.5%, and 18.5%. Bacillus coli was not detected.
基金Under the auspices of the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA2307050103)National Natural Science Foundation of China(No.42071064,41877095)the Project of Changchun Science and Technology Plan(No.19SS019)。
文摘Conservation tillage as an effective alternative to mitigate soil degradation has attracted worldwide attention,but the influences of conservation tillage on soil microbial community and especially function remain unclear.Shotgun metagenomics sequencing was performed to examine the taxonomic and functional community variations of black soils under three tillage regimes,namely no-tillage with residue(maize straw)return(NTS),moldboard plow with residue return(MPS),and moldboard plow without residue return(MPN)in Northeast China.The results revealed:1)Soil bacterial and archaeal communities differed significantly under different tillage regimes in contrast to soil fungal community.2)The overlay of less tillage and residues return under NTS led to unique soil microbial community composition and functional composition.Specifically,in contrast to other treatments,NTS increased the relative abundances of some taxa such as Bradyrhizobium,Candidatus Solibacter,and Reyranella,along with the relative abundances of some taxa such as Sphingomonas,Unclassified Chloroflexi and Nitrososphaera decreased;NTS had a unique advantage of increasing the relative abundances of genes involved in‘ATP-binding cassette(ABC)transporters’and‘quorum sensing(QS)’pathways,while MPN favored the genes involved in‘flagellar assembly’pathway and some metabolic pathways such as‘carbon’and‘glyoxylate and dicarboxylate’and‘selenocompound’metabolisms.3)Significantly different soil bacterial phyla(Acidobacteria,Gemmatimonadetes,and Chloroflexi)and metabolic pathways existed between MPN and another two treatments(NTS and MPS),while did not exist between NTS and MPS.4)Dissolved organic carbon(DOC)and soil bulk density were significantly affected(P<0.05)by tillage and accounted for the variance both in microbial(bacterial)community structure and functional composition.These results indicated that a change in tillage regime from conventional to conservation tillage results in a shift of microbial community and functional genes,and we inferred that residue return played a more prominent role than less tillage in functional shifts in the microbial community of black soils.
基金supported by the earmarked fund for China Agriculture Research System(CARS-23-B04)the National Key Research and Development Program of China(2016YFD0201001)HAAFS Science and Technology Innovation Special Project,China(2022KJCXZX-ZHS-2).
文摘Partial substitution of inorganic fertilizers with organic amendments is an important agricultural management practice.An 11-year field experiment(22 cropping periods)was carried out to analyze the impacts of different partial substitution treatments on crop yields and the transformation of nitrogen fractions in greenhouse vegetable soil.Four treatments with equal N,P_(2)O_(5),and K_(2)O inputs were selected,including complete inorganic fertilizer N(CN),50%inorganic fertilizer N plus 50%pig manure N(CPN),50%inorganic fertilizer N plus 25%pig manure N and 25%corn straw N(CPSN),and 50%inorganic fertilizer N plus 50%corn straw N(CSN).Organic substitution treatments tended to increase crop yields since the 6th cropping period compared to the CN treatment.From the 8th to the 22nd cropping periods,the highest yields were observed in the CPSN treatment where yields were 7.5-11.1%greater than in CN treatment.After 11-year fertilization,compared to CN,organic substitution treatments significantly increased the concentrations of NO_(3)^(-)-N,NH_(4)^(+)-N,acid hydrolysis ammonium-N(AHAN),amino acid-N(AAN),amino sugar-N(ASN),and acid hydrolysis unknown-N(AHUN)in soil by 45.0-69.4,32.8-58.1,49.3-66.6,62.0-69.5,34.5-100.3,and 109.2-172.9%,respectively.Redundancy analysis indicated that soil C/N and OC concentration significantly affected the distribution of N fractions.The highest concentrations of NO_(3)^(-)-N,AHAN,AAN,AHUN were found in the CPSN treatment.Organic substitution treatments increased the activities ofβ-glucosidase,β-cellobiosidase,N-acetyl-glucosamidase,L-aminopeptidase,and phosphatase in the soil.Organic substitution treatments reduced vector length and increased vector angle,indicating alleviation of constraints of C and N on soil microorganisms.Organic substitution treatments increased the total concentrations of phospholipid fatty acids(PLFAs)in the soil by 109.9-205.3%,and increased the relative abundance of G^(+)bacteria and fungi taxa,but decreased the relative abundance of G-bacteria,total bacteria,and actinomycetes.Overall,long-term organic substitution management increased soil OC concentration,C/N,and the microbial population,the latter in turn positively influenced soil enzyme activity.Enhanced microorganism numbers and enzyme activity enhanced soil N sequestration by transforming inorganic N to acid hydrolysis-N(AHN),and enhanced soil N supply capacity by activating non-acid hydrolysis-N(NAHN)to AHN,thus improving vegetable yield.Application of inorganic fertilizer,manure,and straw was a more effective fertilization model for achieving sustainable greenhouse vegetable production than application of inorganic fertilizer alone.
基金supported by the National Key Research and Development Program of China (2016YFD0201001)the earmarked fund for China Agriculture Research System (CARS-23-B02)the Key Research and Development Program of Shandong Province,China (2017CXGC0206)
文摘Greenhouse vegetable production has been characterized by high agricultural inputs, high temperatures, and high cropping indexes. As an intensive form of agriculture, nutrient cycling induced by microbial activities in the greenhouses is relatively different from open fields in the same region. However, the responses of soil microbial biomass carbon (MBC) and nitrogen (MBN), enzyme activities, microbial community composition, and yield to organic amendment are not well understood. Therefore, a 5-year greenhouse tomato (Solanum lycopersicum Mill.)-cucumber (Cucumis sativus L.) rotation experiment was conducted. The field experiment comprised 5 treatments: 4/4CN (CN, nitrogen in chemical fertilizer), 3/4CN+1/4MN (MN, nitrogen in pig manure), 2/4CN+2/4MN, 2/4CN+1/4 MN+1/4 SN (SN, nitrogen in corn straw) and 2/4CN+2/4SN. The amounts of nitrogen (N), phosphorus (P2O5), and potassium (K2O) were equal in the five treatments. Starting with the fourth growing season, the optimal yield was obtained from soil treated with straw. MBC, MBN, phospholipid fatty acid (PLFA) profiles, and enzyme activities were significantly changed by 5 years of substitution with organic amendments. Redundancy analysis showed that MBC accounts for 89.5 and 52.3% of the total enzyme activity and total community variability, respectively. The activities of phosphomonoesterase, N-acetyl-glucosaminidase, and urease, and the relative abundances of fungi, actinomycetes, and Gram-negative bacteria were significantly and positively related to vegetable yields. Considering the effects of organic amendments on soil microbial characteristics and vegetable yield, 2/4CN+1/4MN+1/4SN can improve soil quality and maintain sustainable high yield in greenhouse vegetable production.
基金This research was funded by the National Natural Science Foundation of China(42171033,41807518,41701045)the Shanxi Provincial Natural Science Foundation of China(201801D221336)the Scientific and Technological Innovation Programs of Higher Education Institutions in Shanxi Province,China(2019L0457,2019L0463).
文摘Soil erosion is a serious issue in the sandy-hilly region of Shanxi Province,Northwest China.There has been gradual improvement due to vegetation restoration,but soil microbial community characteristics in different vegetation plantation types have not been widely investigated.To address this,we analyzed soil bacterial and fungal community structures,diversity,and microbial and soil environmental factors in Caragana korshinskii Kom.,Populus tomentosa Carr.,Populus simonii Carr.,Salix matsudana Koidz,and Pinus tabulaeformis Carr.forests.There were no significant differences in the dominant bacterial community compositions among the five forest types.The alpha diversity of the bacteria and fungi communities showed that ACE(abundance-based coverage estimator),Chao1,and Shannon indices in C.korshinskii forest were significantly higher than those in the other four forest types(P<0.05).Soil organic matter,total nitrogen,and urease had a greater impact on bacterial community composition,while total nitrogen,β-glucosidase,and urease had a greater impact on fungal community composition.The relative abundance of beneficial and pathogenic microorganisms was similar across all forest types.Based on microbial community composition,diversity,and soil fertility,we ranked the plantations from most to least suitable as follows:C.korshinskii,S.matsudana,P.tabulaeformis,P.tomentosa,and P.simonii.
文摘Dust fallout can have diverse impacts ranging from major health problems to environmental concerns. It can harbour disease-causing microorganisms and toxic heavy metals, and it is therefore critical to establish the microbial and the mineral compositions of the dust fallout in a particular site and elucidate the possible related health implications for humans and the entire environment. In this study, dust fallout samples were collected from Arandis, a town in the Erongo region (Namibia), using the American Society for Testing and Materials standard method (ASTM D1739) for collection and analysis of dust fallout (settleable particulate matter). The identification of present viable bacteria was done through culturing and isolation techniques and the morphological characteristics, and the elemental composition of the dust fallout were determined using the Stereomicroscope and the X-ray fluorescence, respectively. The results showed that the most dominant bacteria contained in the fallout dust were the Bacillus species. The morphological characterisation revealed that the present particles were mixed black, brownish, greenish, and crystal particles with irregular, cubical, flocks and flake shapes. The elemental investigations indicated that the dust fallout contained Hg, As, Fe, Ni, Cr, Mn, Al and Pb occurring in varying concentrations and the status of pollution of the dust fallout ranged from low to severe concerning the inconsistent heavy metal indices that are the contamination factor, pollution load index and the enrichment factor.
基金supported by National Natural Science Foundation of China(31625006,31988102 and 32001133)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDA23080302).
文摘Background:Nitrogen(N)and phosphorus(P)deposition have largely affected soil respiration(Rs)in forest ecosystems.However,few studies have explored how N and P individually or in combination to influence Rs and its components(autotrophic respiration,Ra;heterotrophic respiration,Rh),especially in highly P-limited subtropical forests.To address this question,we conducted a field manipulation experiment with N and/or P addition in a 50-year-old subtropical secondary forest.Results:We found that N addition on average reduced Rs,Ra,and Rh by 15.2%,15%,and 11.7%,respectively during 2-year field study.P addition had an inconsistent effect on Ra,with Ra increasing by 50.5%in the first year but reducing by 26.6%in the second year.Moreover,P addition on average decreased Rh by 8.9%–30.9%and Rs by 6.7%–15.6%across 2 years.In contrast,N and P co-addition on average increased Rs,Ra,and Rh by 1.9%,7.9%,and 2.1%during the experimental period.Though Rs and Rh were significantly correlated with soil temperature,their temperature sensitivities were not significantly changed by fertilization.Ra was predominantly regulated by soil nitrogen availability(NH4+and NO3−),soil dissolved organic carbon(DOC),and enzyme activities,while the variation in Rh was mainly attributable to changes in soil microbial community composition and soilβ-D-Cellubiosidase(CB)andβ-Xylosidase(XYL)activities.Conclusion:Our findings highlight the contrasting responses of Rs and its components to N or P addition against N and P co-addition,which should be differentially considered in biogeochemical models in order to improve prediction of forest carbon dynamics in the context of N and P enrichment in terrestrial ecosystems.
基金funded by the Scientific Project of Gansu Province,China(20JR5RA548)the National Natural Science Foundation of China(31860148)+1 种基金the Natural Science Foundation of Gansu Province,China(21JR1RM333)the Doctoral Program of Longdong University,China(XYBY1909)。
文摘The Loess Plateau,located in Gansu Province,is an important energy base in China because most of the oil and gas resources are distributed in Gansu Province.In the last 40 a,ecological environment in this region has been extremely destroyed due to the over-exploitation of crude-oil resources.Remediation of crude-oil contaminated soil in this area remains to be a challenging task.In this study,in order to elucidate the effects of organic compost and biochar on phytoremediation of crude-oil contaminated soil(20 g/kg)by Calendula officinalis,we designed five treatments,i.e.,natural attenuation(CK),planted C.officinalis only(P),planted C.officinalis with biochar amendment(PB),planted C.officinalis with organic compost amendment(PC),and planted C.officinalis with co-amendment of biochar and organic compost(PBC).After 152 d of cultivation,total petroleum hydrocarbons(TPH)removal rates of CK,P,PB,PC and PBC were 6.36%,50.08%,39.58%,73.10%and 59.87%,respectively.Shoot and root dry weights of C.officinalis significantly increased by 172.31%and 80.96%under PC and 311.61%and 145.43%under PBC,respectively as compared with P(P<0.05).Total chlorophyll contents in leaves of C.officinalis under P,PC and PBC significantly increased by 77.36%,125.50%and 79.80%,respectively(P<0.05)as compared with PB.Physical-chemical characteristics and enzymatic activity of soil in different treatments were also assessed.The highest total N,total P,available N,available P and SOM(soil organic matter)occurred in PC,followed by PBC(P<0.05).C.officinalis rhizospheric soil dehydrogenase(DHA)and polyphenol oxidase(PPO)activities in PB were lower than those of other treatments(P<0.05).The values of ACE(abundance-based coverage estimators)and Chao 1 indices for rhizospheric bacteria were the highest under PC followed by PBC,P,PB and CK(P<0.05).However,the Shannon index for bacteria was the highest under PC and PBC,followed by P,PB and CK(P<0.05).In terms of soil microbial community composition,Proteiniphilum,Immundisolibacteraceae and Solimonadaceae were relatively more abundant under PC and PBC.Relative abundances of Pseudallescheria,Ochroconis,Fusarium,Sarocladium,Podospora,Apodus,Pyrenochaetopsis and Schizothecium under PC and PBC were higher,while relative abundances of Gliomastix,Aspergillus and Alternaria were lower under PC and PBC.As per the nonmetric multidimensional scaling(NMDS)analysis,application of organic compost significantly promoted soil N and P contents,shoot length,root vitality,chlorophyll ratio,total chlorophyll,abundance and diversity of rhizospheric soil microbial community in C.officinalis.A high p H value and lower soil N and P contents induced by biochar,altered C.officinalis rhizospheric soil microbial community composition,which might have restrained its phytoremediation efficiency.The results suggest that organic compost-assisted C.officinalis phytoremediation for crude-oil contaminated soil was highly effective in the Loess Plateau,China.
基金This research was supported by the National Natural Science Foundation of China(Grant Nos.41877074 and 42077072).
文摘Litter microorganisms play a crucial role in the biological decomposition in forest ecosystems;however,the coupling effect of meteorological and substrate changes on it during the different stages of leaf decomposition in situ remains unclear.Hence,according to meteorological factors dynamics,a one-year field litter of Quercus wutaishanica in situ decomposition experiment was designed for four decay stages in a warm temperate forest.Microbial community composition was characterized using Illumina sequencing of fungal ITS and bacterial 16S genes.Bacterial(6.6)and fungal(3.6)Shannon indexes were the largest after 125 days’litter decomposition(October).The relative abundance of Acidobacteria after 342 days and Bacteroidetes after 125 days were 3 and 24 times higher than after 31 days,respectively.Some non-dominant species(bacteria:Firmicutes,Planctomycotes,and Verrucomicrobia;fungi:Chytridiomycota and Glomeromomycota)may be absent or present at different decomposition stages due to litter properties or meteorological factors.Chemoheterotrophy and aerobic-chemoheterotrophy were the dominant bacterial functional groups,and the dominant fungal functional groups were saprotrophs,pathotrophs,and symbiotrophs.Precipitation and relative humidity significantly affected bacteria.Temperature,sunlight intensity,and net radiation significantly affected fungi.Besides,among the relative contributions of changes in bacterial and fungal community structure,leaf litter properties alone explained the variation of 5.51%and 10.63%.Microbial diversity and decay stage directly affected the litter mass-loss rate,with meteorological factors(precipitation,relative humidity,air temperature,and sunlight intensity)being indirect.Our findings highlight the importance of microbial diversity for leaf litter decomposition and the influence of meteorological factors.
基金supported by the National Natural Science Foundation of China (51778603)the Chinese Academy of Sciences(QYZDY-SSW-DQC004)
文摘As widespread wetland plants,Phragmites play a vital role in water purification and are widely utilized in constructed wetlands(accounting for 15.5%of applied wetland plants)as a natural alternative to wastewater treatment.However,despite such common applications,current understanding of the basic composition of the Phragmites root-inhabiting microbiome and the complex functions of each member of this microbiome remains incomplete,especially regarding pollution remediation.This review summa-rizes the advances that have been made in ecological and biochemical research on the Phragmites root microbiome,including bacteria,archaea,and fungi.Based on next-generation sequencing,microbial com-munity compositions have been profiled under various environmental conditions.Furthermore,culture-based methods have helped to clarify the functions of the microbiome,such as metal iron stabilization,organic matter degradation,and nutrient element transformation.The unique community structure and functions are highly impacted by Phragmites lineages and environmental factors such as salinity.Based on the current understanding of the Phragmites root microbiome,we propose that synthetic microbial com-munities and iron–manganese plaque could be applied and intensified in constructed wetlands to help promote their water purification performance.
基金supported by grants from the Kearney Foundationthe Andrew W.Mellon Foundationthe Department of Energy-Great Lakes Bioenergy Research Center(DOE-GLBRC)funding.
文摘During the past two decades interest in linking soil microbial community composition and activity with ecosystem scale field studies of nutrient cycling or plant community response to disturbances has grown.Despite its importance there are challenges in making this linkage.Foremost is the question of analytical feasibility.In general,microbiological community-level methodologies have not been readily adaptable to the large sample sizes necessary for ecosystem-scale research.As a result,it has been difficult to generate compatible microbial and ecosystem data sets.Soil lipid analysis shows potential as a middle ground between simple biomass measures and molecular profiling.However,the two protocols that have most often been followed are either rapid but indiscriminate(total lipid analysis or fatty acid methyl ester analysis;FAME),or precise but time consuming(phospholipid fatty acid analysis;PLFA).In this paper we report results from a standardized soil used test a modified extraction method(the‘hybrid’method)developed to balance the speed of FAME and the precision of PLFA in order to increase sample throughput.In comparing the three methods,we find that FAME and PLFA are qualitatively and quantitatively distinct.The FAME method yielded the highest fatty acid abundance,but also had high variance resulting in low precision.The PLFA method had precision,but low yield.The‘hybrid’method fell midway between FAME and PLFA for quantitative fatty acid yield.In addition,the hybrid extraction can be completed in a fraction of the time it takes for PLFA.The hybrid protocol appears to provide an optimal balance between effort and accuracy and therefore is a good choice for large-scale ecosystem studies.
基金supported by the National Key Research and Development Program of China (No. 2016YFC0502501)the Special Funds for Local Science and Technology Development Guided by the Central Government, China (No. Guike ZY20198009)+2 种基金the Natural Science Foundation of Guangxi (Nos. 2015GXNSFGA139010 and 2017GXNSFBA198204)the Science and Technology Development Fund of Guangxi Academy of Agricultural Sciences (No. 2018YT07)the Fundamental Research Funds of CAGS (No. 2020022)。
文摘There is limited knowledge about microbial communities and their ecological functions in karst caves with high CO_(2)concentrations.Here,we studied the microbial community compositions and functions in Shuiming Cave( "SMC",CO_(2)concentration 3 303 ppm) and Xueyu Cave( "XYC",CO_(2)concentration 8 753 ppm) using Illumina MiSeq high-throughput sequencing in combination with BIOLOG test.The results showed that Proteobacteria,Actinobacteria and Bacteroidetes were dominant phyla in these two caves,and Thaumarchaeota was the most abundant in the rock wall samples of SMC.The microbial diversity in the water samples decreased with increasing HCO_(3)^(-)concentration,and it was higher in XYC than that in SMC.The microbial community structures in the sediment and rock wall samples were quite different between the two caves.High concentrations of CO_(2)can reduce the microbial diversity on the rock walls in karst caves,probably through changing microbial preference for different types of carbon sources and decreasing the microbial utilization rate of carbon sources.These results expanded our understanding of microbial community and its response to environments in karst caves with high CO_(2).
基金National Natural Science Foundation of China(30970497)Knowledge Innovation Program of the Chinese Academy of Sciences(KZCX2-YW-JC401).
文摘Aims Better understanding of microbial compositional and physiological acclimation mechanisms is critical for predicting terrestrial ecosystem responses to global change.The aim is to assess variations in soil microbial communities under future scenarios of changing precipitation and N deposition in a semiarid grassland of northern China.Methods In order to explicitly estimate microbial responses,a field experiment with water and N addition was established in April 2005 and continuously conducted for 4 years.Specifically,soil microbial community composition and microbial C utilization potential were determined by phospholipid fatty acid(PLFA)and community-level physiological profiles,respectively.Important Findings Water addition had no effects on the PLFA concentrations of grampositive(GP)and negative bacteria(GN),total bacteria and fungi.However,N addition caused significant reductions in the PLFA concentrations of GP,GN,total bacteria and fungi and thus decreased total PLFA of microbial communities.Moreover,there were interactive effects of water and N addition on GN/GPand the ratio of fungal to bacterial PLFA(F/B).In addition,synergistic effects were found between water and nitrogen in affecting microbial C utilization potentials,which implies that microbial C utilization potentials tend to be enhanced when both N and water availability are sufficient.Overall,the microbial responses to water and N addition support our hypothesis that water and N addition may be combined together to affect microbial communities in the semiarid grassland.
基金The National Natural Science Foundation of China(31770531,32001174)the Key Research Program of Frontier Sciences,CAS(QYZDB-SSW-DQC006)+1 种基金the Key Laboratory of Geographical Processes and Ecological Security of Changbai Mountains,Ministry of Education(GPES201902)the Youth Innovation Promotion Association CAS to Chao Wang(2018231).
文摘Background:Freeze–thaw events are common in boreal and temperate forest ecosystems and are increasingly infuenced by climate warming.Soil microorganisms play an important role in maintaining ecosystem stability,but their responses to freeze–thaw cycles(FTCs)are poorly understood.We conducted a feld freeze–thaw experiment in a natural Korean pine and broadleaf mixed forest in the Changbai Mountain Nature Reserve,China,to determine the dynamic responses of soil microbial communities to FTCs.Results:Bacteria were more sensitive than fungi to FTCs.Fungal biomass,diversity and community composition were not signifcantly afected by freeze–thaw regardless of the stage.Moderate initial freeze–thaw resulted in increased bacterial biomass,diversity,and copiotrophic taxa abundance.Subsequent FTCs reduced the bacterial biomass and diversity.Compared with the initial FTC,subsequent FTCs exerted an opposite efect on the direction of change in the composition and function of the bacterial community.Soil water content,dissolved organic carbon,ammonium nitrogen,and total dissolved phosphorus were important factors determining bacterial community diversity and composition during FTCs.Moreover,the functional potentials of the microbial community involved in C and N cycling were also afected by FTCs.Conclusions:Diferent stages of FTCs have diferent ecological efects on the soil environment and microbial activities.Soil FTCs changed the soil nutrients and water availability and then mainly infuenced bacterial community composition,diversity,and functional potentials,which may disturb C and N states in this temperate forest soil.This study also improves our understanding of microbial communities regulating their ecological functions in response to climate change.
基金the Spanish Ministry of Science and the Spanish Research Council(CSIC)call“I-COOP Suelos y Legumbres 2016”for the funded project(2016SU0013)supported by the Universidad Nacional,Costa Rica(grant number SIA-0249-18)。
文摘The impact of forest microhabitats on physiochemical properties of the soil and that of microbial communities on tropical soils remain poorly understood.To elucidate the effect of tropical forest stand on leaf litter and soil microbial communities,we studied enzyme activities,microbial biomass,and diversity in three distinct microhabitats in terms of plant richness,diameter at breast height(DBH),and physiochemical properties of soil and litter,each associated with a different Vanilla sp.In the soil,positive correlations were found between electrical conductivity(EC)and total organic carbon(TOC)with phosphatase activity,and between nitrogen(N)and water-soluble carbon(WSC)content with urease activity(UA).In the litter,the water content was positively correlated with bacterial and fungal biomass,and N and WSC contents were positively correlated with fungal biomass.Positive correlations were found between plant richness and UA in the soil,plant richness and fungal biomass in the soil and litter,and DBH and fungal biomass in the litter.Amplicon sequencing revealed differences between microhabitats in the relative abundance of some fungal and bacterial taxa and in the bacterial community composition of both litter and soil.Bacterial richness and diversity were different between microhabitats,and,in litter samples,they were negatively correlated with DBH and plant richness,respectively.By contrast,none of the soil and litter physiochemical properties were significantly correlated with microbial diversity.Our results show that significant shifts in enzyme activity,microbial biomass,and diversity in the microhabitats were driven by key abiotic and biotic factors depending on the soil or litter sample type.
基金supported by the National Natural Science Foundation of China(Nos.51879228,51769034)the National Science Funds for Creative Research Groups of China(No.51421006)the Priority Academic Program Development of Jiangsu Higher Education Institutions。
文摘Numerous studies have evaluated the toxicity and endocrine disrupting properties of organic UV filters for aquatic organisms,but little is known about their biodegradation in river sediments and their impact on microorganisms.We have set up the sterile and microbiological systems in the laboratory,adding 2-ethylhexyl-4-methoxycinnamate(EHMC),one of organic UV filters included in the list of high yield chemicals,at concentrations of 2,20 and 200μg/L,and characterized the microbial community composition and diversity in sediments.Monitoring of EHMC degradation within 30 days revealed that the half-life in the microbial system(3.49 days)was much shorter than that in the sterile system(7.55 days).Two potential degradation products,4-mercaptobenzoic acid and 3-methoxyphenol were identified in the microbial system.Furthermore,high-throughput 16s and 18s rRNA gene sequencing showed that Proteobacteria dominated the sediment bacterial assemblages followed by Chloroflexi,Acidobacteria,Bacteroidetes and Nitrospirae;Eukaryota_uncultured fungus dominated the sediment fungal assemblages.Correlation analysis demonstrated that two bacterium genera(Anaerolineaceae_uncultured and Burkholderiaceae_uncultured)were significantly correlated with the biodegradation of EHMC.These results illustrate the biodegradability of EHMC in river sediments and its potential impact on microbial communities,which can provide useful information for eliminating the pollution of organic UV filters in natural river systems and assessing their potential ecological risks.