Toxicity-data of two carbamate insecticides, carbaryl and carbofuran, and three fungicides, ziram, zineb and mancozeb with rice-field N2-fixing cyanobacterium Cylindrospermum sp., obtained by in vitro growth and at so...Toxicity-data of two carbamate insecticides, carbaryl and carbofuran, and three fungicides, ziram, zineb and mancozeb with rice-field N2-fixing cyanobacterium Cylindrospermum sp., obtained by in vitro growth and at soil-water interface, were analyzed by the probit method. Growth enhancing concentration, no-observed effective concentration, minimum inhibitory concentration, the highest permissive concentration and lethal concentration100 （LCloo） were determined experimentally. The LC^o values of carbaryl, carbofuran, ziram, zineb and mancozeb in N2-fixing liquid medium were 56.2, 588.8, 0.07, 4.2 and 3.4 IJg/mL, respectively, whereas the corresponding LCloo values were 100.0, 1500.0, 0.17, 25.0 and 9.0 IJg/mL, respectively. The LC50 values of these pesticides in succession in N2-fixing agar medium were 44.7, 239.9, 0.07, 1.8 and 2.3 IJg/mL, respectively, whereas the corresponding LC100 values were 100.0, 600.0, 0.17, 10.0 and 7.0 IJg/mL, respectively. Similar results with nitrate supplemented liquid and agar media indicated that nitrate supplementation had toxicity reducing effect. The LCso and LC^oo values of toxicity in the N2-fixing liquid medium at soil-water interface were 91.2 and 200.0 IJg/mL for carbaryl, 2 317 and 6 000 pg/mL for carbofuran, 0.15 and 0.50 pg/mL for ziram, 16.4 and 50.0 pg/mL for zineb, and 7.2 and 25.0 pg/mL for mancozeb, respectively. Each LC^oo value at soil- water interface with a pesticide was significantly higher than its corresponding LCloo value at liquid/agar media. It can be concluded that, under the N2-fixing conditions, the cyanobacterium tolerated higher levels of each pesticide at soil-water interface.展开更多
Iron(Fe)is an important element for the terrestrial and marine ecosystems through its biogeochemical cycling on the Earth’s surface.China has a long rice cultivation history,with extensive rice distribution across ma...Iron(Fe)is an important element for the terrestrial and marine ecosystems through its biogeochemical cycling on the Earth’s surface.China has a long rice cultivation history,with extensive rice distribution across many types of paddy soils.Paddy soils are the largest anthropogenic wetlands on earth with critical roles in ecosystem functions.The periodic artificial submergence and drainage during paddy soil evolution result in significant changes in soil moisture regime and redox conditions from the natural soils,which facilitate the increase of Fe solubility and mobilization.However,there is a lack of systematic assessment on the magnitude of the migration and loss amount of Fe from paddy soils.In order to quantify the Fe loss and assess the dynamic evolution of Fe in the soils after rice cultivation,seven paddy soil chronosequences derived from different landscapes(bog,plain,terrace)and parent materials(acidic,neutral,calcareous)with cultivation history from 0 to 2,000 yr were studied.Results showed that the rates and trajectories of Fe evolution showed distinct patterns among the studied seven paddy soil chronosequences.However,net losses of Fe from 1 m soil depth occurred at all studied paddy soil chronosequences regardless of the original landscapes and parent materials.Fe in the paddy soils derived from the calcareous lacustrine sediments in the bog area showed a slight accumulation during the initial stage(50 yr)of paddy cultivation,with a loss rate of0.026 kg m^(-2)yr^(-1) during the 50-to 500-yr time period.For the paddy soils developed on the calcareous marine sediments in the plain area,Fe evolution was dominated by the internal movement in soil profiles through coupled reducing-eluviation reactions in the surface horizons and oxidation-illuviation in the subsurface horizons within 1,000 yr of paddy cultivation,with an averaged net loss rate of 0.029 kg m^(-2)yr^(-1) during the 1,000-to 2,000-yr time period of rice cultivation.In contrast,Fe in the paddy soils derived from the acidic and neutral paren展开更多
Rice planting(RP)is significant to methane(CH4_(4))emissions from paddy fields,but its effect on the relative contribution of the acetoclastic methanogenesis to total CH4_(4) production(F_(ac))and the fraction of CH4_...Rice planting(RP)is significant to methane(CH4_(4))emissions from paddy fields,but its effect on the relative contribution of the acetoclastic methanogenesis to total CH4_(4) production(F_(ac))and the fraction of CH4_(4) oxidized(Fox)is poorly understood.To quantify the responses of the F_(ac) and Fox to RP,we investigated CH4_(4) fluxes,CH4_(4) production and oxidation potentials,dissolved CH4_(4) concentrations,and their stable carbon isotopes in a flooded paddy soil.The mcrA and pmoA gene copies were also determined by quantitative polymerase chain reaction(qPCR).Compared with the unplanted soil(control,CK),the seasonal CH4_(4) emissions from the planted soil were significantly enhanced,13.6 times,resulting in large decreases in the CH4_(4) concentrations in the soil solution.This indicated that much more CH4_(4) was released into the atmosphere by the RP than was stored in the soils.Acetoclastic methanogenesis became more important from the tillering stage(TS)to the ripening stage(RS)for the CK,with F_(ac) values increased from 17%-20% to 46%-55%.With RP,the F_(ac) values were enhanced by 10%-20%,and it significantly increased the copy numbers of the mcrA gene at the four rice stages(TS,booting stage(BS),grain-filling stage(GS),and RS).Furthermore,the effect of the RP on the abundance of the mcrA gene was highly concurrent with the effect on the F_(ac) values.At the TS,the Fox values at the soil-water interface were around 50%-75% for the CK,being 15%-20% lower than those of the RP in the rhizosphere.It increased to 65%-100% at the GS,but was reduced by 20%-30% after the RP.These differences might be because the copy numbers of the pmoA gene were significantly raised at the TS while lowered at the GS by the RP.This was further demonstrated by the strong correlations between the effect of the RP on the abundance of the pmoA gene and the effect on the Fox values.These findings suggest that RP markedly impacts on the abundances of the mcrA and pmoA genes,affecting the pathway of CH4_(4) production and the fracti展开更多
The redox-sensitive elements,such as iron,manganese,sulfur,phosphorus,and arsenic,shift their speciation every millimeter(mm)across the soil-water interface in the flooded soil environments.Monitoring of element speci...The redox-sensitive elements,such as iron,manganese,sulfur,phosphorus,and arsenic,shift their speciation every millimeter(mm)across the soil-water interface in the flooded soil environments.Monitoring of element speciation at this high-resolution(HR)within the SWI is still difficult.The key challenge lies in obtaining sufficient porewater samples at specific locations along the soil gradient for downstream analysis.Here with an optimized inductively coupled plasma mass spectrometry(ICP-MS)method and a HR porewater sampler,we demonstrate mm-scale element profiles mapping across the SWI in paddy soils.Highconcentrations of iron and manganese(>10 mg/L)were measured by ICP-MS in an extended dynamic range mode to avoid signal overflow.The iron profile along the SWI generated by the ICP-MS method showed no significant difference(p<0.05)compared to that measured independently using a colorimetric method.Furthermore,four arsenic(arsenite,arsenate,monomethylarsonic and dimethylarsinic acid),two phosphorus(phosphite and phosphate)and two sulfur(sulfide and sulfate)species were separated in 10 min by ion chromatography-ICP-MS with the NH_(4)HCO_(3)mobile phase.We verified the technique using paddy soils collected from the field,and present the mm-scale profiles of iron,manganese,and arsenic,phosphorus,sulfur species(relative standard deviation<8%).The technique developed in this study will significantly promote the measurement throughput in limited samples(e.g.100μL)collected by HR samplers,which would greatly facilitate redox-sensitive elements biogeochemical cycling in saturated soils.展开更多
基金supported by an ES project on ‘Cyanobacteria’ (Grant No.21 (0859)/11/EMR-II),from Council of Scientific and Industrial Research (CSIR),New Delhi,India
文摘Toxicity-data of two carbamate insecticides, carbaryl and carbofuran, and three fungicides, ziram, zineb and mancozeb with rice-field N2-fixing cyanobacterium Cylindrospermum sp., obtained by in vitro growth and at soil-water interface, were analyzed by the probit method. Growth enhancing concentration, no-observed effective concentration, minimum inhibitory concentration, the highest permissive concentration and lethal concentration100 （LCloo） were determined experimentally. The LC^o values of carbaryl, carbofuran, ziram, zineb and mancozeb in N2-fixing liquid medium were 56.2, 588.8, 0.07, 4.2 and 3.4 IJg/mL, respectively, whereas the corresponding LCloo values were 100.0, 1500.0, 0.17, 25.0 and 9.0 IJg/mL, respectively. The LC50 values of these pesticides in succession in N2-fixing agar medium were 44.7, 239.9, 0.07, 1.8 and 2.3 IJg/mL, respectively, whereas the corresponding LC100 values were 100.0, 600.0, 0.17, 10.0 and 7.0 IJg/mL, respectively. Similar results with nitrate supplemented liquid and agar media indicated that nitrate supplementation had toxicity reducing effect. The LCso and LC^oo values of toxicity in the N2-fixing liquid medium at soil-water interface were 91.2 and 200.0 IJg/mL for carbaryl, 2 317 and 6 000 pg/mL for carbofuran, 0.15 and 0.50 pg/mL for ziram, 16.4 and 50.0 pg/mL for zineb, and 7.2 and 25.0 pg/mL for mancozeb, respectively. Each LC^oo value at soil- water interface with a pesticide was significantly higher than its corresponding LCloo value at liquid/agar media. It can be concluded that, under the N2-fixing conditions, the cyanobacterium tolerated higher levels of each pesticide at soil-water interface.
基金supported by the National Natural Science Foundation of China(Grant Nos.41967001&41401238)State Key Laboratory of Soil and Sustainable Agriculture,Institute of Soil Science,Chinese Academy of Sciences(Grant No.Y20160001)Science and Technology Project of Guizhou Province(Grant No.Qian Ke He[2017]1209)。
文摘Iron(Fe)is an important element for the terrestrial and marine ecosystems through its biogeochemical cycling on the Earth’s surface.China has a long rice cultivation history,with extensive rice distribution across many types of paddy soils.Paddy soils are the largest anthropogenic wetlands on earth with critical roles in ecosystem functions.The periodic artificial submergence and drainage during paddy soil evolution result in significant changes in soil moisture regime and redox conditions from the natural soils,which facilitate the increase of Fe solubility and mobilization.However,there is a lack of systematic assessment on the magnitude of the migration and loss amount of Fe from paddy soils.In order to quantify the Fe loss and assess the dynamic evolution of Fe in the soils after rice cultivation,seven paddy soil chronosequences derived from different landscapes(bog,plain,terrace)and parent materials(acidic,neutral,calcareous)with cultivation history from 0 to 2,000 yr were studied.Results showed that the rates and trajectories of Fe evolution showed distinct patterns among the studied seven paddy soil chronosequences.However,net losses of Fe from 1 m soil depth occurred at all studied paddy soil chronosequences regardless of the original landscapes and parent materials.Fe in the paddy soils derived from the calcareous lacustrine sediments in the bog area showed a slight accumulation during the initial stage(50 yr)of paddy cultivation,with a loss rate of0.026 kg m^(-2)yr^(-1) during the 50-to 500-yr time period.For the paddy soils developed on the calcareous marine sediments in the plain area,Fe evolution was dominated by the internal movement in soil profiles through coupled reducing-eluviation reactions in the surface horizons and oxidation-illuviation in the subsurface horizons within 1,000 yr of paddy cultivation,with an averaged net loss rate of 0.029 kg m^(-2)yr^(-1) during the 1,000-to 2,000-yr time period of rice cultivation.In contrast,Fe in the paddy soils derived from the acidic and neutral paren
基金financially supported by the National Key Research and Development Program of China(No.2017YFD 0300105)the National Natural Science Foundation of China(Nos.41571232,41671241,and 41877325)+1 种基金the Youth Innovation Promotion Association of Chinese Academy of Sciences(CASmember No.2018349)。
文摘Rice planting(RP)is significant to methane(CH4_(4))emissions from paddy fields,but its effect on the relative contribution of the acetoclastic methanogenesis to total CH4_(4) production(F_(ac))and the fraction of CH4_(4) oxidized(Fox)is poorly understood.To quantify the responses of the F_(ac) and Fox to RP,we investigated CH4_(4) fluxes,CH4_(4) production and oxidation potentials,dissolved CH4_(4) concentrations,and their stable carbon isotopes in a flooded paddy soil.The mcrA and pmoA gene copies were also determined by quantitative polymerase chain reaction(qPCR).Compared with the unplanted soil(control,CK),the seasonal CH4_(4) emissions from the planted soil were significantly enhanced,13.6 times,resulting in large decreases in the CH4_(4) concentrations in the soil solution.This indicated that much more CH4_(4) was released into the atmosphere by the RP than was stored in the soils.Acetoclastic methanogenesis became more important from the tillering stage(TS)to the ripening stage(RS)for the CK,with F_(ac) values increased from 17%-20% to 46%-55%.With RP,the F_(ac) values were enhanced by 10%-20%,and it significantly increased the copy numbers of the mcrA gene at the four rice stages(TS,booting stage(BS),grain-filling stage(GS),and RS).Furthermore,the effect of the RP on the abundance of the mcrA gene was highly concurrent with the effect on the F_(ac) values.At the TS,the Fox values at the soil-water interface were around 50%-75% for the CK,being 15%-20% lower than those of the RP in the rhizosphere.It increased to 65%-100% at the GS,but was reduced by 20%-30% after the RP.These differences might be because the copy numbers of the pmoA gene were significantly raised at the TS while lowered at the GS by the RP.This was further demonstrated by the strong correlations between the effect of the RP on the abundance of the pmoA gene and the effect on the Fox values.These findings suggest that RP markedly impacts on the abundances of the mcrA and pmoA genes,affecting the pathway of CH4_(4) production and the fracti
基金supported by the National Science Foundation of China(Nos.41977320,41571305)Key Programme Special Fund of XJTLU(No.KSF-A-20)。
文摘The redox-sensitive elements,such as iron,manganese,sulfur,phosphorus,and arsenic,shift their speciation every millimeter(mm)across the soil-water interface in the flooded soil environments.Monitoring of element speciation at this high-resolution(HR)within the SWI is still difficult.The key challenge lies in obtaining sufficient porewater samples at specific locations along the soil gradient for downstream analysis.Here with an optimized inductively coupled plasma mass spectrometry(ICP-MS)method and a HR porewater sampler,we demonstrate mm-scale element profiles mapping across the SWI in paddy soils.Highconcentrations of iron and manganese(>10 mg/L)were measured by ICP-MS in an extended dynamic range mode to avoid signal overflow.The iron profile along the SWI generated by the ICP-MS method showed no significant difference(p<0.05)compared to that measured independently using a colorimetric method.Furthermore,four arsenic(arsenite,arsenate,monomethylarsonic and dimethylarsinic acid),two phosphorus(phosphite and phosphate)and two sulfur(sulfide and sulfate)species were separated in 10 min by ion chromatography-ICP-MS with the NH_(4)HCO_(3)mobile phase.We verified the technique using paddy soils collected from the field,and present the mm-scale profiles of iron,manganese,and arsenic,phosphorus,sulfur species(relative standard deviation<8%).The technique developed in this study will significantly promote the measurement throughput in limited samples(e.g.100μL)collected by HR samplers,which would greatly facilitate redox-sensitive elements biogeochemical cycling in saturated soils.
