Studies On The Seasonal Changes Of Contents Of Heavy-metal And Adaption Mechanism Of Protective Enzyme In Leaves Of Broussonetia Papyrifera

Phytoremediation refer to a technology that the use of plant removing the soil and water-contaminants and reducing the toxic pollutants for remedation of the polluted environment. Phytoremediation is base on the hyperaccumulator that can absorb excess heavy metals to remediation of contaminated soil. The study of the characteristice of the accumulating of Broussonetia papyrifera that is antimony-hyperaccumulator can directly reflect the ability of heavy metal accumulated and provide a theoretical basis for theecological environment and remediation of contaminated soil. A study was conducted to 4-years old paper mulberry, its associated soil in a antimony mining area in Lengshuijiang city of Hunan Provice,its field sample on April,June,Sebtember and November, taking the method of combining indoor determination. based on the tatal content and the chemical form of antimony,lead,cadmium and zinc from spring to winter, in order to assess their season potentials and adaption mechanism through Plant Physiology in phytoremediation of heavy metal polluted areas.The main contents include:1. Using sequential-extraction Tession method determined the contents of Sb,Cd,Pb and Zn in different fraction,the result showed that soil of the mining area were highly contaminated by Sb,Cd and Pb, fllowed by Zn, was respectively 140,9 and 400 times than the background value of heavy metals in HuNan.2.Analysised the water bound fraction,Echangeablefraction,Carbonate-Bound fraction,Fe-MnOxide-Bound fraction Ogranc-Bound fraction and Residual Fraction of Sb,Cd,Pb and Zn,the results show the antimony Mine soil of Sb,Pb and Zn are mainly residual fraction. The order of the contents of Sb differents fraction was:residual-Bound fraction> Fe-Mn oxidation state form> organic form> Fe-Mn form> exchangeable form> water-form.The order of the contents of Pb different form was:residual form> exchangeable form> organic bound form> Fe-Mn oxide form> carbonate form.The order of the condents Zn each form was:residual fraction> organically bound fraction> Fe Manganese oxidation fraction> carbonate fraction> exchangeable fraction.The order of Cd different fraction was:exchangeable form> carbonate form> residual form> Fe-Mn oxidation form> organic form.3. Compared with the contents of the surface soil,middle soil and subsoil of Sb,Pb,Cd and Zn,showes that the pollution soures are from the mining environment and the surface soil accumulate the most contents of Sb,Pb,Cd and Zn in three depth soil.4. Compared with the seasons contents of each fraction of Sb,Pd,Cd and Zn,the sesults show that the contents of the water form,exchangeable form,carbonate form of Sb is constant rise and organic and residual form increased first and then decreased from spring to winter. The contents of exchangeable form,carbonate form and residual form of Pb was constant rise and Fe-Mn Oxide and organic form desend first and then ascended as the seasons.the residual and organic form of Cd was constant go up and exchangeable,carbonate and Fe-Mn oxide form was rise first and then down. The effective form of Zn continue to rise and residual and organic form was continuing downward trend with the four seasons.5. Combined with analysis of variance indicated that the contents of effective formt of Sb,Pb,Cd and Zn have a significant difference in the seasons,but no difference in residual and organic forms.6. Compared with non-pulluded paper mulberry,the use of atomic absorption sepectrophotometry,determined the contents of Sb,Pb,Cd and Zn of paper mulberry's leaves in four seasons,the result showed the contents of broussonetia papyrifera in antimony mine is higher than cK. The seasonal trend of Sb in leaves were first increased and then decreased and was the highest contents in the autumn. The contents,of Pb and Zn in paper mulberry continued to rise in four seasons.Analysis of variance showed that there is the significant difference in four seasons.7. the CF of paper mulberry of Sb coose to 1 and was the maximum in the autumn,while Pb and zn was the maximum in the winter. Combined with the heavy metal 'sfraction analysis showed that contents of Pb,Cd and Pb in leaves has significantly related to its water form,exchangeable,carbonate and Fe-Mn oxide form without related to its organic and residual form.8. Compared with paper mulberry with non-pulluted, the SOD,POD,CAT and MDA activity were measured.The results show that the enzymatic activity paper mulberry in contaminated area is higher than CK,POD,SOD,CAT and MDA activity is first increased and then decline in four seasons and were maximum in the autumn,while the MDA content continued to increase.Analysis of variance showed that there is significant difference from spring to winter.9. Correlation analysis showed that:the POD,SOD,CAT and MDA activity was significantly correlated with the exchangeable and carbonate form of Sb,no correlation with the residual. There is sinificatly relate to the exchangeable and carbonate and Fe-Mn oxide form of Pb,no relation to the organic and residual form. There is significantly correlated with the exchangeable,carbonate,Fe-Mn oxide and organic form of Cd. There was significantly associated with exchangeable and carbonate form and has negatively correlated with organic and residual.