This paper presents an assessment of land use changes and their impacts on the ecosystem in the Montado, a traditional agricultural landscape of Portugal in response to global environmental change. The assessment uses...This paper presents an assessment of land use changes and their impacts on the ecosystem in the Montado, a traditional agricultural landscape of Portugal in response to global environmental change. The assessment uses an agent-based model (ABM) of the adaptive decisions of farmers to simulate the influence on future land use patterns of socio-economic attributes such as social relationships and farmer reliance on subsidies and biophysical constraints. The application and development of the ABM are supported empirically using three categories of input data: 1) farmer types based on a cluster analysis of socio-economic attributes;2) agricultural suitability based on regression analysis of historical land use maps and biophysical attributes;and 3) future trends in the economic and climatic environments based on the A1fi scenario of the Intergovernmental Panel on Climate Change. Model sensitivity and uncertainty analyses are carried out prior to the scenario analysis in order to verify the absence of systematic errors in the model structure. The results of the scenario analysis show that the area of Montado declines significantly by 2050, but it remains the dominant land use in the case study area, indicating some resilience to change. An important policy challenge arising from this assessment is how to encourage next generation of innovative farmers to conserve this traditional landscape for social and ecological values.展开更多
Fixed and random effect models were applied to a pseudo-panel data built of soil analysis reports from tobacco farms to analyze relationships between soil characteristics like soil organic matter (SOM) and soil nitrog...Fixed and random effect models were applied to a pseudo-panel data built of soil analysis reports from tobacco farms to analyze relationships between soil characteristics like soil organic matter (SOM) and soil nitrogen (N), phosphorous (P) and potassium (K) and to explore the potential for improving nutrients availability by increasing SOM content. These econometric models may account for unobserved specific characteristics such as location-specific characteristics, management strategies, farmers’ skills and preferences and environmental heterogeneity. Positive relationships were found between N, P and K availability and SOM. The random effect model reports a highly significant elasticity of N with respect to SOM of 0.75, meaning that an increase of 1% of SOM will increase soil N by 0.75%. Using this elasticity, the required SOM improvement of green manure was calculated at which costs of green manure would exactly equal benefits in terms of reduced N fertilizer use. Costs and benefits are equal if the SOM increases from 1.55% to 3.61%, which is barely achieved according to the literature. Hence, growing green manure crops to increase SOM and thereby N availability is not economically attractive. However, additional benefits may arise from SOM improvement and growing green manure crops.展开更多
Fruiting bodies from the Agaricus genus have been found to contain non-toxic arsenobetaine（AB） as a major compound. It is unknown whether AB is formed during the vegetative or reproductive life stages of the fungus,...Fruiting bodies from the Agaricus genus have been found to contain non-toxic arsenobetaine（AB） as a major compound. It is unknown whether AB is formed during the vegetative or reproductive life stages of the fungus, or by the surrounding microbial community, but AB＇s structural similarity to glycine betaine has led to the hypothesis that AB may be adventitiously accumulated as an osmolyte. To investigate the potential formation of AB during the reproductive life stage of Agaricus species, growth substrate and fungi were collected during the commercial growth of Agaricus bisporus and analyzed for arsenic speciation using HPLC-ICP-MS. AB was found to be the major arsenic compound in the fungus at the earliest growth stage of fruiting（the primordium）. The growth substrate mainly contained arsenate（As（V））. The distribution of arsenic in an A. bisporus primordium grown on As（V） treated substrate, and in a mature Agaricus campestris fruiting body collected from arsenic contaminated mine tailings, was mapped using two dimensional XAS imaging. The primordium and stalk of the mature fruiting body were both found to be growing around pockets of substrate material containing higher As concentrations, and AB was found exclusively in the fungal tissues. In the mature A. campestris the highest proportion of AB was found in the cap, supporting the AB as an osmolyte hypothesis. The results have allowed us to pinpoint the fungus life stage at which AB formation takes place,namely reproduction, which provides a direction for further research.展开更多
China’s high ambitions to reach peak CO_(2) emissions by 2030 and carbon neutrality by 2060 make carbon mitigation an urgent issue with widespread societal consequences.To develop an achievable roadmap and an effecti...China’s high ambitions to reach peak CO_(2) emissions by 2030 and carbon neutrality by 2060 make carbon mitigation an urgent issue with widespread societal consequences.To develop an achievable roadmap and an effective portfolio of climate policies,it is essential that a clear picture of the magnitude and uncertainty of China’s current carbon balance is available,at both national and regional levels.展开更多
Arsenic contamination is a major environmental issue,as it may lead to serious health hazard.The reduced trivalent formof inorganic arsenic,arsenite,is in generalmore toxic to plants comparedwith the fully oxidized pe...Arsenic contamination is a major environmental issue,as it may lead to serious health hazard.The reduced trivalent formof inorganic arsenic,arsenite,is in generalmore toxic to plants comparedwith the fully oxidized pentavalent arsenate.Theuptakeof arsenite inplants hasbeenshown tobemediatedthrough a large subfamily of plant aquaglyceroporins,nodulin 26-like intrinsic proteins(NIPs).However,the efflux mechanisms,as well as themechanismof arsenite-induced root growth inhibition,remain poorly understood.Usingmolecular physiology,synchrotron imaging,and root transport assay approaches,we show that the cellular transport of trivalent arsenicals inArabidopsis thalianais stronglymodulatedbyPINFORMED2(PIN2)auxin efflux transporter.Root transport assay using radioactive arsenite,X-ray fluorescence imaging(XFI)coupled with X-ray absorption spectroscopy(XAS),and inductively coupled plasma mass spectrometry analysis revealed that pin2 plants accumulate higher concentrations of arsenite in roots comparedwith the wild-type.At the cellular level,arsenite specifically targets intracellular sorting of PIN2 and thereby alters the cellular auxin homeostasis.Consistently,loss of PIN2 function results in arsenite hypersensitivity in roots.XFI coupled with XAS further revealed that loss of PIN2 function results in specific accumulation of arsenical species,but not the other metals such as iron,zinc,or calcium in the root tip.Collectively,these results suggest that PIN2 likely functions as an arsenite efflux transporter for the distribution of arsenical species in planta.展开更多
基金jointly supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(CAS)[grant number XDA19030403]the National Natural Science Foundation of China [grant number 41575095]+2 种基金the CAS ‘Belt and Road Initiatives’ Program on International Cooperation [grant number 134111KYSB20160010]Victor Nnamdi DIKE acknowledges support from the CAS–TWAS(The World Academy of Sciences)President FellowshipHyacinth NNAMCHI is supported by the International Federation for Science(W/4849)
基金jointly supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(CAS)[grant number XDA19030403]the National Natural Science Foundation of China [grant numbers 41575095 and41661144032]+1 种基金the CAS ‘Belt and Road Initiatives’ Program on International Cooperation [grant number134111KYSB20160010]Victor Nnamdi DIKE acknowledges the support of a CAS-TWAS President Fellowship
基金funded through the VISTA Project that was carried out by the authors at the Département de Géologie et de Géographie,Universite catholique de Louvain,BelgiumVISTA was funded within the 5th Framework Programme of the European Commission.
文摘This paper presents an assessment of land use changes and their impacts on the ecosystem in the Montado, a traditional agricultural landscape of Portugal in response to global environmental change. The assessment uses an agent-based model (ABM) of the adaptive decisions of farmers to simulate the influence on future land use patterns of socio-economic attributes such as social relationships and farmer reliance on subsidies and biophysical constraints. The application and development of the ABM are supported empirically using three categories of input data: 1) farmer types based on a cluster analysis of socio-economic attributes;2) agricultural suitability based on regression analysis of historical land use maps and biophysical attributes;and 3) future trends in the economic and climatic environments based on the A1fi scenario of the Intergovernmental Panel on Climate Change. Model sensitivity and uncertainty analyses are carried out prior to the scenario analysis in order to verify the absence of systematic errors in the model structure. The results of the scenario analysis show that the area of Montado declines significantly by 2050, but it remains the dominant land use in the case study area, indicating some resilience to change. An important policy challenge arising from this assessment is how to encourage next generation of innovative farmers to conserve this traditional landscape for social and ecological values.
文摘Fixed and random effect models were applied to a pseudo-panel data built of soil analysis reports from tobacco farms to analyze relationships between soil characteristics like soil organic matter (SOM) and soil nitrogen (N), phosphorous (P) and potassium (K) and to explore the potential for improving nutrients availability by increasing SOM content. These econometric models may account for unobserved specific characteristics such as location-specific characteristics, management strategies, farmers’ skills and preferences and environmental heterogeneity. Positive relationships were found between N, P and K availability and SOM. The random effect model reports a highly significant elasticity of N with respect to SOM of 0.75, meaning that an increase of 1% of SOM will increase soil N by 0.75%. Using this elasticity, the required SOM improvement of green manure was calculated at which costs of green manure would exactly equal benefits in terms of reduced N fertilizer use. Costs and benefits are equal if the SOM increases from 1.55% to 3.61%, which is barely achieved according to the literature. Hence, growing green manure crops to increase SOM and thereby N availability is not economically attractive. However, additional benefits may arise from SOM improvement and growing green manure crops.
基金supported by the US Department of Energy-Basic Energy Sciencesthe Canadian Light Source and its funding partnerssupported by the U.S. DOE under Contract No.DE-AC02-06CH11357
文摘Fruiting bodies from the Agaricus genus have been found to contain non-toxic arsenobetaine（AB） as a major compound. It is unknown whether AB is formed during the vegetative or reproductive life stages of the fungus, or by the surrounding microbial community, but AB＇s structural similarity to glycine betaine has led to the hypothesis that AB may be adventitiously accumulated as an osmolyte. To investigate the potential formation of AB during the reproductive life stage of Agaricus species, growth substrate and fungi were collected during the commercial growth of Agaricus bisporus and analyzed for arsenic speciation using HPLC-ICP-MS. AB was found to be the major arsenic compound in the fungus at the earliest growth stage of fruiting（the primordium）. The growth substrate mainly contained arsenate（As（V））. The distribution of arsenic in an A. bisporus primordium grown on As（V） treated substrate, and in a mature Agaricus campestris fruiting body collected from arsenic contaminated mine tailings, was mapped using two dimensional XAS imaging. The primordium and stalk of the mature fruiting body were both found to be growing around pockets of substrate material containing higher As concentrations, and AB was found exclusively in the fungal tissues. In the mature A. campestris the highest proportion of AB was found in the cap, supporting the AB as an osmolyte hypothesis. The results have allowed us to pinpoint the fungus life stage at which AB formation takes place,namely reproduction, which provides a direction for further research.
基金supported by the National Key Research&Development Program of China(2018YFA0606001)the National Natural Science Foundation of China(41977404)。
文摘China’s high ambitions to reach peak CO_(2) emissions by 2030 and carbon neutrality by 2060 make carbon mitigation an urgent issue with widespread societal consequences.To develop an achievable roadmap and an effective portfolio of climate policies,it is essential that a clear picture of the magnitude and uncertainty of China’s current carbon balance is available,at both national and regional levels.
基金supported in part by the Iwate University President Fund(to A.R.)Global Innovation Fund,University of Saskatchewan(to I.P.,G.N.G.,and A.R.)+7 种基金supported by grants from the Natural Sciences and Engineering Research Council of Canada(G.N.G.,I.P.)the Saskatchewan Health Research Foundation(G.N.G.,I.P.)The University of Saskatchewan,and Canada Research Chairs(G.N.G.,I.P.)supported by the US Department of Energy(DOE)Office of Science User Facility operated for the DOE Office of Science by Argonne National Laboratory under contract no.DE-AC02-06CH11357supported by the US DOE,Office of Science,Office of Basic Energy Sciences under contract no.DE-AC02-76SF00515supported by the DOE Office of Biological and Environmental Researchby the National Institutes of Health(NIH)National Institute of General Medical Sciences(NIGMS)(including P41GM103393)。
文摘Arsenic contamination is a major environmental issue,as it may lead to serious health hazard.The reduced trivalent formof inorganic arsenic,arsenite,is in generalmore toxic to plants comparedwith the fully oxidized pentavalent arsenate.Theuptakeof arsenite inplants hasbeenshown tobemediatedthrough a large subfamily of plant aquaglyceroporins,nodulin 26-like intrinsic proteins(NIPs).However,the efflux mechanisms,as well as themechanismof arsenite-induced root growth inhibition,remain poorly understood.Usingmolecular physiology,synchrotron imaging,and root transport assay approaches,we show that the cellular transport of trivalent arsenicals inArabidopsis thalianais stronglymodulatedbyPINFORMED2(PIN2)auxin efflux transporter.Root transport assay using radioactive arsenite,X-ray fluorescence imaging(XFI)coupled with X-ray absorption spectroscopy(XAS),and inductively coupled plasma mass spectrometry analysis revealed that pin2 plants accumulate higher concentrations of arsenite in roots comparedwith the wild-type.At the cellular level,arsenite specifically targets intracellular sorting of PIN2 and thereby alters the cellular auxin homeostasis.Consistently,loss of PIN2 function results in arsenite hypersensitivity in roots.XFI coupled with XAS further revealed that loss of PIN2 function results in specific accumulation of arsenical species,but not the other metals such as iron,zinc,or calcium in the root tip.Collectively,these results suggest that PIN2 likely functions as an arsenite efflux transporter for the distribution of arsenical species in planta.
