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| Citric acid chelation induced extraction and remediation of heavy metal polluted soils by arbuscular mycorrhizal fungi combined with Medicago sativa |
| Received:March 06, 2025 |
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| KeyWord:arbuscular mycorrhizal fungi;chelator;phytoextraction;mycorrhizal colonization rate;acid-extractable metal |
| Author Name | Affiliation | | QIU Lang | School of Environment and Surveying Engineering, Suzhou University, Suzhou 234000, China
Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China | | XIA Yifan | School of Environment and Surveying Engineering, Suzhou University, Suzhou 234000, China | | YANG Jing | School of Environment and Surveying Engineering, Suzhou University, Suzhou 234000, China | | WANG Zhigang | College of Geoscience and Surveying Engineering, China University of Mining and Technology-Beijing, Beijing 100083, China | | YU Longsheng | Guangzhou Research Institute of Environmental Protection, Guangzhou 510620, China | | ZHANG Yanxu | State Key Laboratory for Fine Exploration and Intelligent Development of Coal Resources, China University of Mining and Technology-Beijing, Beijing 100083, China |
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| Abstract: |
| The present study aimed to explore the combined effect of arbuscular mycorrhizal fungi（AMF）and citric acid（CA）chelating agents on the phytoremediation of heavy metal contaminated soil with Medicago sativa. A greenhouse pot experiment was conducted to investigate the effects of AMF inoculation on M. sativa growth, the concentration and accumulation of heavy metal V, Cd, Cr, Cu, Pb, and As, and soil acid-extractable metal concentration under different levels（0, 5, and 10 mmol · kg-1） of CA application in the soil contaminated with complex heavy metals. Compared with the non-CA treatment, 5 and 10 mmol · kg-1 CA treatments significantly decreased the root mycorrhizal colonization, shoot and root dry weight of M. sativa by 15.1%-19.2%（P<0.05）, 17.0%-27.4% and 26.2%- 37.1%（P<0.01）, respectively; while they significantly enhanced the concentration of heavy metals V, Cd, Cr, Cu, Pb, and As in the plant and bioconcentration factor（P<0.001）, with an increased heavy metal concentration of 71.0, 3.60, 12.4, 2.87, 14.7 times, and 5.09 times for plant shoot and 1.87, 4.94, 2.68, 2.87, 9.66 times, and 4.12 times for plant root, respectively. AMF inoculation could alleviate the inhibition effect of CA application, and AMF inoculation treatments significantly improved plant dry weight（P<0.001）, and decreased the concentrations of V, Cd, Cr, Pb, and As in the shoot and root when compared to non-AMF inoculation. The combination treatment of AMF inoculation and 10 mmol·kg-1 CA could significantly increase the accumulation of V, Cd, Cr, Cu, Pb, and As in plant shoot and root（P< 0.001）, showing the best heavy metals removal efficiency. The analysis of variance results showed that the concentrations of acidextractable metals V, Cd, Cr, Cu, Pb and As in the rhizosphere soil were significantly affected by CA factor（P<0.001）. The univariate linear regression equation of plant shoot V, Cd, Cr, Cu, Pb and As accumulation and rhizosphere soil acid-extractable metal concentration were established, and the coefficients of determination（R2）for six heavy metals were above 0.60. Combination of 10 mmol·kg-1 CA and AMF inoculation could accumulate heavy metals to the plant aboveground due to the increased soil available heavy metal concentration in soil, and AMF inoculation could alleviate the growth inhibition effect of CA application, thus improving the phytoextraction efficiency of M. sativa for remediation of heavy metal contaminated soil. |
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