Crassipes And Big Piao Experimental Study On The Enrichment Of Uranium And Tolerance Mechanism

Great deals of waste rocks, tailing and percolate from tailing were produced in theprocess of uranium mining and metallurgy, which brought the radioactive pollution towater bodies. Compared with the traditional physical and chemical remediationtechnologies, phytoremediation has the investment to maintain low cost, easy tooperate, does not cause secondary pollution, especially suitable for large-area waterpollution repair. Thus, phytoremediation of uranium pollution in the rehabilitation ofwater are highly valued. Eichhornia crassipes and Pistia stratiotes were two commonplants for repairing water pollution. A hoagland hydroponic experiment was carriedout to study the short-duration （8d） accumulation ability of uranium by E. crassipesand P. stratiotes under different uranium concentration. Effects on photosyntheticpigment content, superoxide dismutase activity, catalase activity, peroxidase activity,malondialdehyde （MDA） and free proline content of E. crassipes and P. stratiotesunder uranium stress.The results showed that low concentrations of uranium processing did notproduce toxic effects on E. crassipes and P. stratiotes growth. Uranium concentrationgreater than0.1mg·L^-1stress, the leaf and root damage ratings of E. crassipes wereless than P. stratiotes, indicating that a relatively small uranium stress damage on theleaves and roots of E. crassipes and E. crassipes tolerated higher uraniumconcentrations than P. stratiotes.The photosynthetic pigment content of E. crassipesand P. stratiotes were no significant （P>0.05） change under0.1mg·L^-1uranium stressbut as the concentration increased the content were continued to decreased. Under0.1¹mg·L^-1uranium stress, the activity of antioxidant enzymes were increased andMDA content were at lower level means that antioxidant enzymes played animportant role in alleviating lipid peroxidation induced by uranium stress. Under5mg·L^-1uranium stress, the antioxidant enzymes activity of E. crassipes at higherlevel and MDA content was lower but the P. stratiotes was opposite, indicating that E.crassipes tolerated higher concentrations than P. stratiotes. Under higher concentration (20mg·L^-1and50mg·L^-1) uranium stress, the activity of antioxidantenzymes were inhibited and induced ROS and H2O2massive accumulation and thenthe MDA content increased. As an important osmoregulation material, free prolinecontent was more than the contrast and played a role in adjusting osmotic underuranium stress and effectively weakened the both plants suffered damage. As theuranium stress concentration increased, the uranium content of the plants alsosignificantly increased. The body uranium content was to1550.2mg·kg-1and963.0mg·kg-1under50mg·L^-1uranium stress, respectively, the uranium were moreaccumulated in roots than shoots. As the uranium stress concentration increased, theBCF of the both plants was decreased. The BCF of E. crassipes was higher than P.stratiotes, indicating that the accumulation capacity of E. crassipes was more than P.stratiotes. But the ability to transfer uranium from the roots to stems and leaves partsof P. stratiotes were better than E. crassipes.