Effect Of Uranium Onantioxidant Enzyme Activity Of Rohdeajaponica And Enrichment Performance

There is only about 1-4mg/kg uranium in the earth’s crust. The uranium mining and metallurgy, as well as surrounding industrial chains are the main source for the uranium pollution in soil and water environments. After being absorbed by animals and plants, uranium shows heavy metaltoxicity and radioactive double toxicity to organisms, while does not participate in any biological functional processes. Therefore, the uranium in soil and water environment greatly threatens ecological environment and human health.Plants can be used to deal with uranium pollution. This processing way is economic and environmentally protective and thus has been widely concerned by researchers. this study researched the activities of a series of antioxidant enzymes(SOD, POD, CAT, GR) and the content of antioxidants(GSH, GSSG) under different uraniumconcentrations(0, 0.1, 1, 5, 10mg/L). Moreover, TEM-EDS(the combination of TEM and EDS) was used to observe correspondingsubcellular structure of Rohdea japonica.This study was attempt to explore the significance of the variations of antioxidant enzyme activity and antioxidant content, the physiological structure response of Rohdea japonica to uranium stress, as well as the distribution law of uranium in the leaves of Rohdea japonica.The results obtained provided scientific basis for the phytoremediation of uranium environmental pollution.The study result showed that, chlorophyll a, chlorophyll b, carotenoids, soluble protein, leaf methane dicarboxylic aldehyde(MDA)content, free proline content, peroxidase(POD) activity, and leaf glutathione reductase(GR) activity increased firstly and then decreased with the increase of uranium concentration(0, 0.1, 1, 5, 10 mg/L); Root and leaf conductivity, root MDA content, reduced glutathione content(GSH), oxidized glutathione(GSSG) content, and catalase(CAT) activity, superoxide dismutase(SOD) activity presented an constantly upward trend; the changes of glutathione reductase(GR) activity in root was unobvious. Uranium stress induced the rise of synthesis amount of protein and proline. Meanwhile, the increase of uranium concentration promoted Rohdea japonica to increase the antioxidant enzyme activity and ascorbic acid- GSH(ASA-GSH) circulation to resist oxidative stress. Transmission electron microscope(TEM) scanning results showed that the membranous system of Rohdea japonica was damaged by uranium of high concentration. The damage on cell membrane, nucleus, mitochondria, and other plasmids were significantly irreversible. X ray energy spectrum(EDS) analysis suggested that uranium mainly distributed in the cell wall and vacuole. After 15 d, uranium sorption capacity reached 1089.04mg/Kg by Rohdea japonica. The result is good which can be used as a potential uranium enrichment plant to study. Uranium adsorption capacity of Rohdea japonica increased with the increasing of uranium concentration, and the adsorption of uranium content in root was more obvious compared with the control group. With the increase of concentration of uranium, the root bioconcentrationfactor decreased gradually and the translocationfactor gradually decreased; The uranium enrichment of Rohdea japonica is mainly in the roots, and the ability to transfer uranium from root decreased with the increased concentration of uranium concentration.