Rice(Oryza sativa L.)farmers face challenges with metal accumulation in grain,with nickel(Ni)recently emerging as a concern due to its potential to exceed legal limits,alongside cadmium(Cd).Information on Ni behaviour...Rice(Oryza sativa L.)farmers face challenges with metal accumulation in grain,with nickel(Ni)recently emerging as a concern due to its potential to exceed legal limits,alongside cadmium(Cd).Information on Ni behaviour and its interaction with Cd remains limited.Selenium(Se)is commonly used for rice biofortification and can reduce the accumulation of toxic metals in plants.Therefore,this study investigates how Ni and Cd influence mutual accumulation in rice and examines the impact of different Se forms on their interactions.Plants were grown hydroponically with various combinations of Cd(5 or 20μmol/L),Ni(20μmol/L),and Se(5μmol/L)as selenate(Se^(6+))or selenite(Se^(4+))for 7 d.Plant growth,lipid peroxidation,and element accumulation were measured,and the distribution of Se and Ni in tissues was assayed using synchrotron-basedμXRF 2D imaging.Cd and Ni were toxic to rice,reducing leaf and root biomass by 40%‒50%and inducing oxidative stress.However,their combined presence did not further exacerbate leaf growth reduction.Cd reduced root Ni accumulation by approximately 50%at equimolar concentrations,likely due to competitive inhibition at shared transport sites.Se promoted root growth in the presence of Ni and low Cd,suggesting an antioxidant role in mitigating metal-induced stress.However,high doses of Ni and Cd together significantly reduced Se accumulation(by 60%and 77%for Se^(4+)in roots and Se^(6+)in leaves,respectively)and caused severe oxidative stress in the presence of Se^(4+).The effectiveness of Se biofortification varied depending on the Se form:Se^(6+)was more effective at reducing Ni accumulation,while Se^(4+)effectively reduced Cd accumulation(by 45%‒75%)at low concentrations and Ni accumulation in the absence of Cd(by 50%).In conclusion,this study demonstrates that Se can mitigate Cd and Ni accumulation in rice.However,the co-presence of Cd and Ni may compromise Se enrichment in rice,highlighting the complexity of their interactions.展开更多
This study identified the role of milling and parboiling on arsenic(As)content and its species in large numbers of rice samples.Total As contents were 108±33μg/kg in polished rice grains(PR),159±46μg/kg in...This study identified the role of milling and parboiling on arsenic(As)content and its species in large numbers of rice samples.Total As contents were 108±33μg/kg in polished rice grains(PR),159±46μg/kg in unpolished rice grains(UR),145±42μg/kg in parboiled polished rice grains(PPR)and 145±44μg/kg in parboiled unpolished rice grains(PUR).The percentages of inorganic As(iAs)were 66%±8%in PR and from 72%to 77%in other grain categories.The polishing process reduced the As content in the rice grains,removing outer part of the UR with high amount of As,whereas the parboiling technique transferred the semimetal content within the grain.Total As and iAs contents were not significantly different in UR,PPR and PUR,homogenizing its distribution inside the grains.The results allowed to understand how different operations affect As fate and its chemical forms in grains.展开更多
基金funded by the European Union’s Horizon 2022 research and innovation program under the Marie SKŁODOWSKA-CURIE Individual Fellowship(Grant No.101105237).
文摘Rice(Oryza sativa L.)farmers face challenges with metal accumulation in grain,with nickel(Ni)recently emerging as a concern due to its potential to exceed legal limits,alongside cadmium(Cd).Information on Ni behaviour and its interaction with Cd remains limited.Selenium(Se)is commonly used for rice biofortification and can reduce the accumulation of toxic metals in plants.Therefore,this study investigates how Ni and Cd influence mutual accumulation in rice and examines the impact of different Se forms on their interactions.Plants were grown hydroponically with various combinations of Cd(5 or 20μmol/L),Ni(20μmol/L),and Se(5μmol/L)as selenate(Se^(6+))or selenite(Se^(4+))for 7 d.Plant growth,lipid peroxidation,and element accumulation were measured,and the distribution of Se and Ni in tissues was assayed using synchrotron-basedμXRF 2D imaging.Cd and Ni were toxic to rice,reducing leaf and root biomass by 40%‒50%and inducing oxidative stress.However,their combined presence did not further exacerbate leaf growth reduction.Cd reduced root Ni accumulation by approximately 50%at equimolar concentrations,likely due to competitive inhibition at shared transport sites.Se promoted root growth in the presence of Ni and low Cd,suggesting an antioxidant role in mitigating metal-induced stress.However,high doses of Ni and Cd together significantly reduced Se accumulation(by 60%and 77%for Se^(4+)in roots and Se^(6+)in leaves,respectively)and caused severe oxidative stress in the presence of Se^(4+).The effectiveness of Se biofortification varied depending on the Se form:Se^(6+)was more effective at reducing Ni accumulation,while Se^(4+)effectively reduced Cd accumulation(by 45%‒75%)at low concentrations and Ni accumulation in the absence of Cd(by 50%).In conclusion,this study demonstrates that Se can mitigate Cd and Ni accumulation in rice.However,the co-presence of Cd and Ni may compromise Se enrichment in rice,highlighting the complexity of their interactions.
文摘This study identified the role of milling and parboiling on arsenic(As)content and its species in large numbers of rice samples.Total As contents were 108±33μg/kg in polished rice grains(PR),159±46μg/kg in unpolished rice grains(UR),145±42μg/kg in parboiled polished rice grains(PPR)and 145±44μg/kg in parboiled unpolished rice grains(PUR).The percentages of inorganic As(iAs)were 66%±8%in PR and from 72%to 77%in other grain categories.The polishing process reduced the As content in the rice grains,removing outer part of the UR with high amount of As,whereas the parboiling technique transferred the semimetal content within the grain.Total As and iAs contents were not significantly different in UR,PPR and PUR,homogenizing its distribution inside the grains.The results allowed to understand how different operations affect As fate and its chemical forms in grains.
