Oxidative potential(OP)can be used as an indicator of the health risks of particulate matter in the air.To study the variation and sources of OP,we conducted an observation of PM_(2.5) in a megacity in southern China ...Oxidative potential(OP)can be used as an indicator of the health risks of particulate matter in the air.To study the variation and sources of OP,we conducted an observation of PM_(2.5) in a megacity in southern China in winter and spring of 2021.The results show that the average concentration of PM_(2.5) decreased by 47%from winter to spring,while volume-normalized and mass-normalized OP(i.e.,OP_(v) and OP_(m))increased by 6%and 69%,respectively.It suggests that the decline of PM_(2.5) may not necessarily decrease the health risks and the intrinsic toxicity of PM_(2.5).Variations of OP_(v) and OP_(m) among different periods were related to the different source contributions and environmental conditions.The positive matrix factorization model was used to identify the major sources of OP_(v).OP_(v) was mainly contributed by biomass burning/industrial emissions(29%),soil/road dust(20%),secondary sulfate(14%),and coal combustion(13%)in winter.Different major sources were resolved to be secondary sulfate(36%),biological sources(21%),and marine vessels(20%)in spring,presenting the substantial contribution of biological sources.The analysis shows strong associations between OP_(v) and both live and dead bacteria,further confirming the important contribution of bioaerosols to the enhancement of OP.This study highlights the importance of understanding OP in ambient PM_(2.5) in terms of public health impact and provides a new insight into the biological contribution to OP.展开更多
Nitrous acid(HONO)is an important source of hydrogen oxides(HOx),which affects air quality,the atmospheric oxidation capacity,and human health.Here,we present ambient measurements of the HONO concentrations in Zhuhai,...Nitrous acid(HONO)is an important source of hydrogen oxides(HOx),which affects air quality,the atmospheric oxidation capacity,and human health.Here,we present ambient measurements of the HONO concentrations in Zhuhai,a coastal city in Southern China,from February 7 to March 15,2021.The campaign was classified into two periods during(P1)and after(P2)the Spring Festival holidays.The average HONO mixing ratio during P2(1.19±0.85 ppbv)was much higher than that during P1(0.24±0.18 ppbv),likely due to the contribution of homogeneous HONO formation.During nighttime,the heterogeneous conversion rate during P2(0.0089/hr)was considerably higher than that during P1(0.0057/hr),suggesting a higher heterogeneous NO_(2) conversion potential.However,the heterogeneous NO_(2) conversion was the dominant way during P1 with a high percentage of 88%,while comparable ratios of heterogeneous and homogeneous formation were found(54%vs.46%)during P2,indicating that the homogeneous formation was also important during P2.During daytime,homogeneous reaction was the major known pathway,with a contribution of 16%during P1 and 27%during P2,leaving large unknown HONO sources which reasonably correlated with the photo-enhanced NO_(2) conversion.Two case scenarios were additionally explored,showing that there might be a primary emission source during one scenario(February 17-18)and vehicle emissions might be the major unknown HONO source for another scenario(March 3–5).The results suggest that large unknown daytime sources still exist which need more future ambient and laboratory studies.展开更多
Seed weight is a pivotal yield-determining trait in crops,and yet,the genetic and molecular mechanisms underlying its regulation in polyploid species remain underexplored.In a previous study,we identified cqSW.A03-2,a...Seed weight is a pivotal yield-determining trait in crops,and yet,the genetic and molecular mechanisms underlying its regulation in polyploid species remain underexplored.In a previous study,we identified cqSW.A03-2,a QTL that regulates thousand seed weight(TSW)in rapeseed(Brassica napus).Here,we identify BnaA3.AHK2,encoding a histidine kinase,as the causal gene of cqSW.A03-2.BnaA3.AHK2 enhances TSW through maternal control of seed coat cell expansion without significantly compromising other yield-related traits.Protein sequence divergence between parental haplotypes caused functional differentiation,with only the ZY50 allele showing functional kinase activity and rescuing developmental defects in Arabidopsis cytokinin receptor mutants.Strikingly,BnaA3.AHK2 seems to be a cytokinin-independent operator,contrasting with the canonical cytokinin signaling pathway.Transcriptome and protein interaction analyses reveal a signaling module where BnaA3.AHK2 engages BnaAHP-Bna ARR phosphorelay components to regulate downstream targets.Notably,the favorable cqSW.A03-2 haplotype has been historically selected in modern breeding,and its introgression into elite hybrids boosted TSW by 3.6%-9.1%,demonstrating its breeding value.Our findings unveil a non-canonical signaling pathway for seed size regulation,providing a strategic genetic target to break yield trade-offs in polyploid crops.展开更多
基金supported by the National Natural Science Foundation of China(No.41975156)and the Fundamental Research Funds for the Central Universities.
文摘Oxidative potential(OP)can be used as an indicator of the health risks of particulate matter in the air.To study the variation and sources of OP,we conducted an observation of PM_(2.5) in a megacity in southern China in winter and spring of 2021.The results show that the average concentration of PM_(2.5) decreased by 47%from winter to spring,while volume-normalized and mass-normalized OP(i.e.,OP_(v) and OP_(m))increased by 6%and 69%,respectively.It suggests that the decline of PM_(2.5) may not necessarily decrease the health risks and the intrinsic toxicity of PM_(2.5).Variations of OP_(v) and OP_(m) among different periods were related to the different source contributions and environmental conditions.The positive matrix factorization model was used to identify the major sources of OP_(v).OP_(v) was mainly contributed by biomass burning/industrial emissions(29%),soil/road dust(20%),secondary sulfate(14%),and coal combustion(13%)in winter.Different major sources were resolved to be secondary sulfate(36%),biological sources(21%),and marine vessels(20%)in spring,presenting the substantial contribution of biological sources.The analysis shows strong associations between OP_(v) and both live and dead bacteria,further confirming the important contribution of bioaerosols to the enhancement of OP.This study highlights the importance of understanding OP in ambient PM_(2.5) in terms of public health impact and provides a new insight into the biological contribution to OP.
基金supported by the National Natural Science Foundation of China(NSFC)(Nos.42175115,41775117)the Guangdong Basic and Applied Basic Research Foundation(No.2022A1515011864)+4 种基金the Guangdong Major Project of Basic and Applied Basic Research(No.2020B0301030004)the Science and Technology Innovation Committee of Guangzhou(No.201803030010)the Scientific and Technological Innovation Team Project of Guangzhou Joint Research Center of Atmospheric Sciences,Science and Technology Program of Guangdong Province(Science and Technology Innovation Platform Category)(No.2019B121201002)the Guangdong Province Key Laboratory for Climate Change and Natural Disaster Studies(No.2020B1212060025)the Fundamental Research Funds for the Central Universities,Sun Yat-sen University(22qntd1907).
文摘Nitrous acid(HONO)is an important source of hydrogen oxides(HOx),which affects air quality,the atmospheric oxidation capacity,and human health.Here,we present ambient measurements of the HONO concentrations in Zhuhai,a coastal city in Southern China,from February 7 to March 15,2021.The campaign was classified into two periods during(P1)and after(P2)the Spring Festival holidays.The average HONO mixing ratio during P2(1.19±0.85 ppbv)was much higher than that during P1(0.24±0.18 ppbv),likely due to the contribution of homogeneous HONO formation.During nighttime,the heterogeneous conversion rate during P2(0.0089/hr)was considerably higher than that during P1(0.0057/hr),suggesting a higher heterogeneous NO_(2) conversion potential.However,the heterogeneous NO_(2) conversion was the dominant way during P1 with a high percentage of 88%,while comparable ratios of heterogeneous and homogeneous formation were found(54%vs.46%)during P2,indicating that the homogeneous formation was also important during P2.During daytime,homogeneous reaction was the major known pathway,with a contribution of 16%during P1 and 27%during P2,leaving large unknown HONO sources which reasonably correlated with the photo-enhanced NO_(2) conversion.Two case scenarios were additionally explored,showing that there might be a primary emission source during one scenario(February 17-18)and vehicle emissions might be the major unknown HONO source for another scenario(March 3–5).The results suggest that large unknown daytime sources still exist which need more future ambient and laboratory studies.
基金supported by the National Natural Science Foundation of China(U23A20190 and 31971977)the Project 2662022ZKYJ004 supported by the Fundamental Research Funds for the Central Universities and the Fund for CAR-12。
文摘Seed weight is a pivotal yield-determining trait in crops,and yet,the genetic and molecular mechanisms underlying its regulation in polyploid species remain underexplored.In a previous study,we identified cqSW.A03-2,a QTL that regulates thousand seed weight(TSW)in rapeseed(Brassica napus).Here,we identify BnaA3.AHK2,encoding a histidine kinase,as the causal gene of cqSW.A03-2.BnaA3.AHK2 enhances TSW through maternal control of seed coat cell expansion without significantly compromising other yield-related traits.Protein sequence divergence between parental haplotypes caused functional differentiation,with only the ZY50 allele showing functional kinase activity and rescuing developmental defects in Arabidopsis cytokinin receptor mutants.Strikingly,BnaA3.AHK2 seems to be a cytokinin-independent operator,contrasting with the canonical cytokinin signaling pathway.Transcriptome and protein interaction analyses reveal a signaling module where BnaA3.AHK2 engages BnaAHP-Bna ARR phosphorelay components to regulate downstream targets.Notably,the favorable cqSW.A03-2 haplotype has been historically selected in modern breeding,and its introgression into elite hybrids boosted TSW by 3.6%-9.1%,demonstrating its breeding value.Our findings unveil a non-canonical signaling pathway for seed size regulation,providing a strategic genetic target to break yield trade-offs in polyploid crops.
