A series of column experiments were performed to investigate the mechanisms of silicon （Si） and heavy metals （HM） interaction in the soil. The column experiments were conducted with Gray Forest Soil treated by var...A series of column experiments were performed to investigate the mechanisms of silicon （Si） and heavy metals （HM） interaction in the soil. The column experiments were conducted with Gray Forest Soil treated by various forms of active Si （diatomaceous earth, zeolite, amorphous silicon dioxide and concentrated monosilicic acid） in environment polluted conditions with soluble salts of Cd, Cu, Ni and Pb. All Si-rich substances used in the test were analyzed with electron scan microscope. The results of HM immobilization in soil by Si-rich materials showed that diatomaceous earth and concentrated monosilicic acid immobilized HM better than zeolite and amorphous silicon dioxide. The reductions in HM mobility were re- alized by the reaction between monosilicic acid and HM in soil solution and by adsorption of HM on Si-rich surface. The intensity of HM movement through soil depended on the type of HM. The maximum reduction of HM mobility with application of Si-rich substances was obtained for Cd and Ni and less effect was observed for Cu and Pb.展开更多
Silicon(Si)is the second most abundant element in the Earth’s crust and has numerous roles in both soils and plants,although it is inaccessible to plants in its native state(insoluble silicate minerals).This inaccess...Silicon(Si)is the second most abundant element in the Earth’s crust and has numerous roles in both soils and plants,although it is inaccessible to plants in its native state(insoluble silicate minerals).This inaccessibility can lead to insufficiency,which induces anomalies in plant growth and development.Specifically,Si alleviates various biotic and abiotic stresses in plants by enhancing tolerance mechanisms at different stages of uptake/deposition as a monosilicic acid.Exclusive utilization of conventional Si fertilizers to boost agricultural productivity in an attempt to meet the world’s ever-increasing food demand may result in surface and groundwater pollution,waterway eutrophication,soil fertility depletion,and accumulation of hazardous elements such as arsenic in soil.By addressing the drawbacks of chemical fertilizers,this review emphasizes an environmentally friendly alternative,namely,Si-solubilizing microorganisms(SSMs),as bioinoculants to liberate soluble Si and thus making it available to plants.A deep understanding of recent advances in the functional diversity,colonization patterns,modes of action,role in biogeochemical cycling,and plant stress tolerance of SSMs and their implementation in Si-based agrowaste management through the fabrication of nanoparticles,could help to establish a reliable tool for economically and environmentally sustainable agriculture.From this perspective,in this review,we comprehensively summarize the latest methodologies for the isolation,screening,and characterization of SSMs and Si solubilization mechanisms,including ligands(divalent cations),acids(inorganic and organic),alkali(nucleophilic attack),extracellular polysaccharides,and factors affecting them,as well as Si-mediated regulation of gene expression involved in Si uptake,transportation,and mineralization.We have critically revised the role of SSMs according to the current literature.The contributions of SSMs to biofertilization are still being explored;hence,we also discuss trajectories for future research in relation to SSM-mediated increases in bioavailable Si.This will create new strategies to reduce the use of agrochemicals,improve plant health,and help us to globally gravitate towards more sustainable agricultural practices,based on the concept of a circular economy.展开更多
基金Supported by the Science and Technology Cooperation Project of China and Russia during 2013-2014 for Control of Farmland Soil Pollution in Dongting Lake Area(CR1605)the General Fund from China Hunan Provincial Science and Technology Department for Technology Introduction and Experimental Study for Control of Farmland Soil Pollution in Dongting Lake Area(2013WK4011)~~
文摘A series of column experiments were performed to investigate the mechanisms of silicon （Si） and heavy metals （HM） interaction in the soil. The column experiments were conducted with Gray Forest Soil treated by various forms of active Si （diatomaceous earth, zeolite, amorphous silicon dioxide and concentrated monosilicic acid） in environment polluted conditions with soluble salts of Cd, Cu, Ni and Pb. All Si-rich substances used in the test were analyzed with electron scan microscope. The results of HM immobilization in soil by Si-rich materials showed that diatomaceous earth and concentrated monosilicic acid immobilized HM better than zeolite and amorphous silicon dioxide. The reductions in HM mobility were re- alized by the reaction between monosilicic acid and HM in soil solution and by adsorption of HM on Si-rich surface. The intensity of HM movement through soil depended on the type of HM. The maximum reduction of HM mobility with application of Si-rich substances was obtained for Cd and Ni and less effect was observed for Cu and Pb.
文摘Silicon(Si)is the second most abundant element in the Earth’s crust and has numerous roles in both soils and plants,although it is inaccessible to plants in its native state(insoluble silicate minerals).This inaccessibility can lead to insufficiency,which induces anomalies in plant growth and development.Specifically,Si alleviates various biotic and abiotic stresses in plants by enhancing tolerance mechanisms at different stages of uptake/deposition as a monosilicic acid.Exclusive utilization of conventional Si fertilizers to boost agricultural productivity in an attempt to meet the world’s ever-increasing food demand may result in surface and groundwater pollution,waterway eutrophication,soil fertility depletion,and accumulation of hazardous elements such as arsenic in soil.By addressing the drawbacks of chemical fertilizers,this review emphasizes an environmentally friendly alternative,namely,Si-solubilizing microorganisms(SSMs),as bioinoculants to liberate soluble Si and thus making it available to plants.A deep understanding of recent advances in the functional diversity,colonization patterns,modes of action,role in biogeochemical cycling,and plant stress tolerance of SSMs and their implementation in Si-based agrowaste management through the fabrication of nanoparticles,could help to establish a reliable tool for economically and environmentally sustainable agriculture.From this perspective,in this review,we comprehensively summarize the latest methodologies for the isolation,screening,and characterization of SSMs and Si solubilization mechanisms,including ligands(divalent cations),acids(inorganic and organic),alkali(nucleophilic attack),extracellular polysaccharides,and factors affecting them,as well as Si-mediated regulation of gene expression involved in Si uptake,transportation,and mineralization.We have critically revised the role of SSMs according to the current literature.The contributions of SSMs to biofertilization are still being explored;hence,we also discuss trajectories for future research in relation to SSM-mediated increases in bioavailable Si.This will create new strategies to reduce the use of agrochemicals,improve plant health,and help us to globally gravitate towards more sustainable agricultural practices,based on the concept of a circular economy.
