Combined Remediation Of Pteris Vittata L. And AM Fungi On U Contaminated Soil

Uranium is an important energy, however, uranium pollution, especially the pollution to soil, becomes more and more serious following many mine exploitation. At present, bioremediation is one green channel due to its economical, practical advantage and no pollution, though many remediation methods have been reported. Studies have shown that centipede grass(Pteris vittata L.) has resistance in uranium contaminated soil, and is susceptible to be infected by arbuscular mycorrhizal(AM) fungi. AM fungi could remediate soil contaminated by harm metals. In the present study, the dominate AM fungus was screened out in centipede grass inoculated with three AM fungi, Glomus etunicatum(Ge), Glomus versiforme(Gv) and Glomus intraradice(Gi). The experiment was carried out to study the effects of mycorrhizal symbiont and citric acid(chelating agent) on uranium contaminated soil. The main research results were as following:1. The results showed that Gv was the dominant species in the rhizosphere of Pteris vittata. The mycorrhizal colonizationand hyphal density in Gv treatments was the highest,with 52.88% and 11.3 m·g-1, Gv group of The biomass of Pteris vittata showed the maximum in Gv treatments, which was were Ge and Gi, this is CK group 1.13 times to Ge, 1.54 times to Gi and 2.17 times to CK.2. The growth in Pteris vittata was promoted by Gv inoculation. During the sameperiods, the biomass were higher in Gv and Gv+O group than CK, and those were higher in Gv group than Gv+O except the date in September in 2013, suggesting that Gv is the main factor in contribution to the growth on Pteris vittata.3. The uranium in Pteris vittata was enriched, especially in roots by Gv inoculation. The bioaccumulation factors(BFS) in Gv and Gv+O group, far more than 1, were higher than CK, indicating that Gv inoculation was benefit to the U accumulation in Pteris vittata. During the same period, the BFS in roots was 3.52 times, 4.32 times, 8.3 times and 18.55 times than the shoots in Gv treatments, and those were 5.31 times, 7.63 times, 7.25 times and 12.00 times in CK+O group, and 12.76 times, 5.67 times, 9.00 times and 55.6 times in Gv+O group, which were far more than CK The above results showed that the Gv inoculummainly promoted the uranium enrichment in roots on Pteris vittata, and alleviated the toxicity of uranium on the host plants4. Gv inoculation was helpful to the transform of different U species, especially the manganese oxides iron and sulfides of uranium.The U contents in rhizospheric soil in Gv group was less than CK, and the absorption to Fe-Mn oxide and sulfide U of Pteris vittata were the best than other U species.5. The chelating agent was beneficial to promote the glomalin secretion so as to be helpful to the U immobilization in roots. Glomalin was not detected in the uninoculated group, and EEG and TG contents in Gv+O group were higher than Gv group.6. Gv promoted the absorption of mineral elements in different tissuesof Pteris vittata. The N contents in roots, stems and leaves of Pteris vittata increased significantly after inoculation with Gv, which were 4.50 times, 3.62 timesand 3.43 times than CK group.7. The mineral elements were significantly positive correlation to the U enriched in Pteris vittata. U was significantly positive correlation with Cu, Fe, Zn, and positively correlated with N, P, Ca, Mg, however, negatively correlated with K.