Cadmium(Cd)uptake by rice plants and its subsequent movement through food chains pose a notable risk to the health of both plants and humans.Therefore,understanding the fundamental mechanisms underlying the uptake and...Cadmium(Cd)uptake by rice plants and its subsequent movement through food chains pose a notable risk to the health of both plants and humans.Therefore,understanding the fundamental mechanisms underlying the uptake and movement process is essential.Through transcriptome analysis,we found that numerous abscisic acid(ABA)-related genes responded to Cd stress.Exogenous application of ABA significantly reduced Cd accumulation in the shoots and roots of rice plants.The increased ascorbate peroxidase(APX)enzyme activity,decreased H2O2 content,and elevated Cd tolerance index collectively suggest that ABA may mitigate the toxicity of Cd in rice plants.Further study revealed that exogenous ABA reduced Cd accumulation by regulating Cd transport and cell wall sequestration.Consistently,mutation of the ABA signaling factor OsABI5 resulted in a significant increase in Cd accumulation in shoots.Moreover,foliar spraying of ABA during the grain-filling stage significantly reduced Cd accumulation in rice grains,which was attributed mainly to decreased Cd uptake and the inhibition of Cd transportation from roots to shoots and from leaves to grains.These findings elucidate the underlying mechanisms of the ABA-mediated response to Cd stress in rice and provide a practical reference for coping with Cd pollution in farmlands.展开更多
Results from laboratory experiments indicated that the concentrations and toxicities of both water-soluble and 0.1 M HCl-extractable Cu and Cd from soils were in the order of red soil> yellow brown earth> black ...Results from laboratory experiments indicated that the concentrations and toxicities of both water-soluble and 0.1 M HCl-extractable Cu and Cd from soils were in the order of red soil> yellow brown earth> black earth.The toxicity of soil varied with the concentrations of metals.The form,concentration and toxicity of Cu and Cd in soils were determined by cation exchange capacity,content of organic matter and composition of clay minerals in the soil.Addition of CaCO3 could significantly decrease the concentration and toxicity of water-soluble and 0.1 M HCl-extractable Cu or Cd from the red soil,and could notably transform the Cu and Cd from the water-soluble or exchangeable form into the organic,free oxides-occluded or sulfic form.展开更多
Reclaimed soils in mining area usually display low fertility and present Cd stress.The amendment of modified biochar effectively fixes Cd in soils,enhances soil fertility,and reduces Cd stress in soil microorganisms.H...Reclaimed soils in mining area usually display low fertility and present Cd stress.The amendment of modified biochar effectively fixes Cd in soils,enhances soil fertility,and reduces Cd stress in soil microorganisms.However,the effect of thiourea-modified biochar(TBC)on microbial adaptability to Cd stress in mining reclamation soils is still unclear.The present work studied the Cd immobilization and microbial community changes in a mining reclamation soil displaying extreme Cd contamination under TBC amendment.The results indicated that the amendment of TBC significantly enhanced(P<0.05)soil pH,the content of available phosphorus(AP),and the activities of urease and polyphenol oxidase by 1.3%,463.4%,54.4%,and 84.0%,respectively,compared to the control without amendment.The amount of toxicity characteristic leaching procedure-extracable Cd decreased(P<0.05)by 68.0%in the TBC-amended soil compared with the unamended soil.The structure of soil microbiota was reorganized and the alpha diversity index was increased in the TBC treatment.The TBC amendment increased the relative abundances of Proteobacteria,Bacteroidota,and Zoopagomycota,which were strongly associated(P<0.01)with higher soil pH and AP.Structural equation model results demonstrated that Cd immobilization was directly influenced by soil pH,AP,and urease,and indirectly affected by bacterial structure in the TBC treatment.The TBC amendment can effectively improve the structural composition of soil bacteria under Cd stress and enhance the pathways of decreasing soil Cd availability as well.The results might facilitate the development of in-situ remediation programs in Cd-contaminated soils in the future.展开更多
基金support from the National Natural Science Foundation of China(U20A2024)the National Key Research and Development Program of China(2023YFD2301300).
文摘Cadmium(Cd)uptake by rice plants and its subsequent movement through food chains pose a notable risk to the health of both plants and humans.Therefore,understanding the fundamental mechanisms underlying the uptake and movement process is essential.Through transcriptome analysis,we found that numerous abscisic acid(ABA)-related genes responded to Cd stress.Exogenous application of ABA significantly reduced Cd accumulation in the shoots and roots of rice plants.The increased ascorbate peroxidase(APX)enzyme activity,decreased H2O2 content,and elevated Cd tolerance index collectively suggest that ABA may mitigate the toxicity of Cd in rice plants.Further study revealed that exogenous ABA reduced Cd accumulation by regulating Cd transport and cell wall sequestration.Consistently,mutation of the ABA signaling factor OsABI5 resulted in a significant increase in Cd accumulation in shoots.Moreover,foliar spraying of ABA during the grain-filling stage significantly reduced Cd accumulation in rice grains,which was attributed mainly to decreased Cd uptake and the inhibition of Cd transportation from roots to shoots and from leaves to grains.These findings elucidate the underlying mechanisms of the ABA-mediated response to Cd stress in rice and provide a practical reference for coping with Cd pollution in farmlands.
文摘Results from laboratory experiments indicated that the concentrations and toxicities of both water-soluble and 0.1 M HCl-extractable Cu and Cd from soils were in the order of red soil> yellow brown earth> black earth.The toxicity of soil varied with the concentrations of metals.The form,concentration and toxicity of Cu and Cd in soils were determined by cation exchange capacity,content of organic matter and composition of clay minerals in the soil.Addition of CaCO3 could significantly decrease the concentration and toxicity of water-soluble and 0.1 M HCl-extractable Cu or Cd from the red soil,and could notably transform the Cu and Cd from the water-soluble or exchangeable form into the organic,free oxides-occluded or sulfic form.
基金supported by the National Natural Science Foundation of China(Nos.41807515,51974313,and 51974314)the Jiangsu Provincial Natural Science Foundation of China(No.BK20180641)。
文摘Reclaimed soils in mining area usually display low fertility and present Cd stress.The amendment of modified biochar effectively fixes Cd in soils,enhances soil fertility,and reduces Cd stress in soil microorganisms.However,the effect of thiourea-modified biochar(TBC)on microbial adaptability to Cd stress in mining reclamation soils is still unclear.The present work studied the Cd immobilization and microbial community changes in a mining reclamation soil displaying extreme Cd contamination under TBC amendment.The results indicated that the amendment of TBC significantly enhanced(P<0.05)soil pH,the content of available phosphorus(AP),and the activities of urease and polyphenol oxidase by 1.3%,463.4%,54.4%,and 84.0%,respectively,compared to the control without amendment.The amount of toxicity characteristic leaching procedure-extracable Cd decreased(P<0.05)by 68.0%in the TBC-amended soil compared with the unamended soil.The structure of soil microbiota was reorganized and the alpha diversity index was increased in the TBC treatment.The TBC amendment increased the relative abundances of Proteobacteria,Bacteroidota,and Zoopagomycota,which were strongly associated(P<0.01)with higher soil pH and AP.Structural equation model results demonstrated that Cd immobilization was directly influenced by soil pH,AP,and urease,and indirectly affected by bacterial structure in the TBC treatment.The TBC amendment can effectively improve the structural composition of soil bacteria under Cd stress and enhance the pathways of decreasing soil Cd availability as well.The results might facilitate the development of in-situ remediation programs in Cd-contaminated soils in the future.
