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
With a high-energy resolution micro-X-ray fluorescence (μ-XRF) analysis setup, which basically consists of an X-ray microbeam formed by an X-ray focusing lens combined with an X-ray apparatus and a wavelength dispers...With a high-energy resolution micro-X-ray fluorescence (μ-XRF) analysis setup, which basically consists of an X-ray microbeam formed by an X-ray focusing lens combined with an X-ray apparatus and a wavelength dispersive position sensitive spectrometer with a flat crystal (PSS), preliminary results have been obtained. The counting rate of the analyzed element linearly increased with the power of X-ray apparatus, and the energy resolution, full width of half maximum (FWHM) of Kα lines of Ti and Cr reached 16.6 and 23.6 eV, respectively. The Cr Kβ and Mn Kα lines in a sample of stainless steel could clearly be resolved. The above-mentioned results are also compared with those obtained by synchrotron radiation light microbeam combined with the PSS. The facts show that the high-energy resolution element analysis is feasible by using the setup. Moreover, problems for the setup and the ways to resolve them are discussed as well.展开更多
Background The increase in the frequency and intensity of droughts is pointed out as one of the main factors altering biogeochemical cycles in the Amazon basin.An eco-nutritional approach using X-ray fluorescence micr...Background The increase in the frequency and intensity of droughts is pointed out as one of the main factors altering biogeochemical cycles in the Amazon basin.An eco-nutritional approach using X-ray fluorescence micro-analysis(μXRF)is proposed to verify the long-and short-term effects of droughts on the growth and xylem nutrient concentrations of Cedrela fissilis Vell.Methods Fourteen radii were selected from a tree-ring width chronology and X-rayed by Itrax Multiscanner.Profiles of ring width,wood density,and concentrations of aluminum(Al),phosphorus(P),sulfur(S),calcium(Ca),potassium(K),manganese(Mn),iron(Fe)and strontium(Sr)together with Al/Ca,Ca/Mn,K/Ca,Sr/Ca and Mn/S ratios were constructed and correlated with precipitation,temperature,the difference between precipitation and potential evapotranspiration(P-PET)and standardized precipitation-evapotranspiration index(SPEI).Results During dry years,C.fissilis showed narrower,less dense rings,lower Al,P,S and Ca,and higher K and Fe concentrations(the opposite was found in wet years).Ring width decreased(together with Al,P,S,K,Ca,Mn,Fe,Sr,Al/Ca,K/Ca and Sr/Ca)and wood density increased(together with Ca/Mn and Mn/S),which was associated with an increase in evapotranspiration and temperature over time,mainly since 1990.Cedrela fissilis showed a tendency to increase its capacity for resistance,and a recovery and resilience in growth over time associated with responses in Al,Ca,P and S.However,it showed a risk in the capacity for recovery of the pre-drought density values,associated with unsatisfactory responses in Al,Ca,K,Fe and P.Conclusions This study is the first attempt to analyze tree-ring nutritional evidences of C.fissilis trees to climate sensitivity and resilience to drought,based on long-term data from seasonal moist tropical forests of the Amazon.Our data suggested that C.fissilis is undergoing alterations in the concentration,use and redistribution of nutrients associated with increasing wood density and decreasing growth over time,due to the increase of drought frequency in the southern Amazon.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With a high-energy resolution micro-X-ray fluorescence (μ-XRF) analysis setup, which basically consists of an X-ray microbeam formed by an X-ray focusing lens combined with an X-ray apparatus and a wavelength dispersive position sensitive spectrometer with a flat crystal (PSS), preliminary results have been obtained. The counting rate of the analyzed element linearly increased with the power of X-ray apparatus, and the energy resolution, full width of half maximum (FWHM) of Kα lines of Ti and Cr reached 16.6 and 23.6 eV, respectively. The Cr Kβ and Mn Kα lines in a sample of stainless steel could clearly be resolved. The above-mentioned results are also compared with those obtained by synchrotron radiation light microbeam combined with the PSS. The facts show that the high-energy resolution element analysis is feasible by using the setup. Moreover, problems for the setup and the ways to resolve them are discussed as well.
基金We thank the Wood Anatomy and Tree-Ring Laboratory(LAIM)(FAPESP project:2009/53951-7)Department of Forest Sciences,Luiz de Queiroz College of Agriculture(ESALQ)+6 种基金DROR was supported by a fellowship from the Fundação de AmparoàPesquisa do Estado do São Paulo(FAPESP,grants#2018/22914-8,2020/04608-7)RSS was supported by VULBOS project(UPO-1263216),VURECLIM(P20_00813)AH by PinCaR project(UHU-1266324)both from FEDER Funds,Andalusia Regional Government,Consejería de Economía,Conocimiento,Empresas y Universidad 2014-2020RSS and AH were also supported by EQC2018-004821-P and IE19_074 UPO projects cofounded by Spanish“Plan Estatal de Investigación Científica y Técnica y de Innovación 2017-2020”and“Plan Andaluz de Invetigación,Desarrollo e Innovación(PAIDI 2020)”,respectivelyRCB was supported from FAPESP(Grant#2020/11502-0)MJF and MTF were supported from FAPESP-FAPEAM(#01/2020)and CAPES(PROCAD/Amazônia,#21/2018)This study was also partially funded by PIRE-project(FAPESP,Grant#2017/50085-3).
文摘Background The increase in the frequency and intensity of droughts is pointed out as one of the main factors altering biogeochemical cycles in the Amazon basin.An eco-nutritional approach using X-ray fluorescence micro-analysis(μXRF)is proposed to verify the long-and short-term effects of droughts on the growth and xylem nutrient concentrations of Cedrela fissilis Vell.Methods Fourteen radii were selected from a tree-ring width chronology and X-rayed by Itrax Multiscanner.Profiles of ring width,wood density,and concentrations of aluminum(Al),phosphorus(P),sulfur(S),calcium(Ca),potassium(K),manganese(Mn),iron(Fe)and strontium(Sr)together with Al/Ca,Ca/Mn,K/Ca,Sr/Ca and Mn/S ratios were constructed and correlated with precipitation,temperature,the difference between precipitation and potential evapotranspiration(P-PET)and standardized precipitation-evapotranspiration index(SPEI).Results During dry years,C.fissilis showed narrower,less dense rings,lower Al,P,S and Ca,and higher K and Fe concentrations(the opposite was found in wet years).Ring width decreased(together with Al,P,S,K,Ca,Mn,Fe,Sr,Al/Ca,K/Ca and Sr/Ca)and wood density increased(together with Ca/Mn and Mn/S),which was associated with an increase in evapotranspiration and temperature over time,mainly since 1990.Cedrela fissilis showed a tendency to increase its capacity for resistance,and a recovery and resilience in growth over time associated with responses in Al,Ca,P and S.However,it showed a risk in the capacity for recovery of the pre-drought density values,associated with unsatisfactory responses in Al,Ca,K,Fe and P.Conclusions This study is the first attempt to analyze tree-ring nutritional evidences of C.fissilis trees to climate sensitivity and resilience to drought,based on long-term data from seasonal moist tropical forests of the Amazon.Our data suggested that C.fissilis is undergoing alterations in the concentration,use and redistribution of nutrients associated with increasing wood density and decreasing growth over time,due to the increase of drought frequency in the southern Amazon.
