交流电场与Fusarium sp.A-2耦合对博落回修复铀污染土壤的强化作用

通过盆栽试验研究了交流电场(AC)与Fusarium sp.A-2(A-2)真菌耦合对博落回(P)的生物量、富集铀(U)性能、酶活性以及根际土壤中有机酸含量、生物可利用态铀、根际微生物群落结构的影响.结果表明, 在铀(U)污染土壤中, 与AC+P+U、A-2+P+U和P+U相比, AC+A-2+P+U组博落回的鲜重、株高、总干重分别升高了10.67%~45.76%、26.87%~92.02%和61.99%~159.98%;总超氧化物歧化酶(T-SOD)和过氧化氢酶(CAT)含量分别提高了41.24%~133%和15.35%~63.63%;根际土壤中草酸显著增加了13.03%~157.09%;与A-2+P+U和P+U组相比, AC+A-2+P+U组土壤中生物可利用态铀分别提高了12.5%和28.57%.在AC+A-2+P+U组, 植物根际土壤中存在大量的镰刀型菌(Fusarium)真菌属和酸杆菌属(Acidobacteria)等细菌菌属, 且镰刀型菌属(Fusarium)占比最高, 与AC+P+U、A-2+P+U、P+U和A-2+U组相比, Fusarium分别提高了16.67%、81.03%、299.23%和374.47%.AC和A-2耦合强化博落回修复铀污染土壤的可能机理包括AC提高了铀在土壤中的流动性, 增加了植物根部与铀的接触, 促进了铀的富集; AC刺激了博落回的生理活性, 增大了博落回的生物量, 提高了抗氧化酶活性, 使博落回对铀的耐受性增强; AC刺激了A-2真菌和酸杆菌属(Acidobacteria)的生长, 使其比例增大, 从而产生大量的有机酸, 与铀形成螯合物, 降低了铀对植物的胁迫作用, 提高了生物可利用态铀的占比, 促进了博落回对铀的富集.AC与A-2真菌耦合对P修复铀污染土壤有显著的强化作用, 是一种有潜在应用前景的强化方法.

Enhancement effects of the coupling between AC electric field and Fusarium sp. A-2 on the remediation of uranium contaminated soil by Macleaya Cordata

Pot experiments were conducted to study the effects of the coupling between alternating current electric field (AC) and Fusarium sp. A-2 (A-2) fungi on the biomass, uranium (U) enrichment and enzyme activity of Macleaya cordata (P), as well as the organic acid content, bioavailable uranium and microbial community structure in the rhizosphere soil. The results showed that compared with AC+P+U, A-2+P+U, and P+U groups, the fresh weight, plant height and total dry weight of Macleaya cordata in AC+A-2+P+U group were significantly increased by 10.67%~45.76%, 26.87%~92.02% and 61.99%~159.98%, respectively, and the contents of the total superoxide dismutase (T-SOD) and catalase (CAT) were increased by 41.24%~133% and 15.35%~63.63%, respectively, and the oxalic acid was increased by 13.03%~157.09%. Compared with the A-2+P+U and P+U groups, the bioavailable uranium in soil in AC+A-2+P+U group was increased by 12.5% and 28.57%, respectively. In the AC+A-2+P+U groups, there were a large number of Fusarium fungi and Acidobacteria in rhizosphere soil, and the proportion of Fusarium fungi was the highest. Compared with AC+P+U, A-2+P+U, P+U, and A-2+U groups, the proportion of Fusarium fungi in AC+A-2+P+U group was increased by 16.67%, 81.03%, 299.23% and 374.47%, respectively. The mechanisms of AC and A-2 coupling enhanced the remediation of uranium contaminated soil by Macleaya cordata may be include that AC improved the mobility of uranium in soil, increased the contact between plant roots and uranium, and promoted the enrichment of uranium by Macleaya cordata; that AC stimulated the physiological activity and increased the biomass of Macleaya cordata, improved the activity of antioxidant enzymes, and enhanced the tolerance of Macleaya cordata to uranium; and that AC stimulated the growth of A-2 fungi and Acidobacteria, increased their proportion, and produced a large number of organic acids which can form chelates with uranium, reduced the stress of uranium on plants, increased the proportion of bioavailable speciation of uranium, and promoted the enrichment of uranium by Macleaya cordata. AC and A-2 coupling exhibited a significant enhancement effect on the remediation of uranium contaminated soil by Macleaya cordata, and there coupling was a promising enhancement method.