The synergistic effect of biochar and arbuscular mycorrhizal fungi on the phytoremediation of cadmium-contaminated soil

Previous studies have demonstrated that both Biochar (BC) and Arbuscular mycorrhizal fungi (AMF) can significantly mitigate Cadmium (Cd) toxicity and alleviate plant stress. To further investigate the individual and interactive effects of these two factors on the phytoremediation of Cd-contaminated soil, a pot experiment was conducted. Under Cd pollution stress, the concurrent application of BC and AMF markedly increased biomass by 40.1% and the root-shoot ratio by 35.9%. The synergistic application of BC and AMF significantly enhanced the Cd concentration in the aboveground biomass of Poa pratensis L. by 37.4%, while increasing it in the underground biomass by 73.8%. During phytoremediation, BC enriches beneficial microbial communities, enhancing Cd fixation by the roots of P. pratensis L. Concurrent inoculation with AMF facilitates the translocation of Cd to the aboveground biomass, thus improving phytoremediation efficiency. Compared to the bioavailability of Cd, plant absorption of Cd is more significantly influenced by the plants' tolerance capacity. Both BC and AMF enhance the Cd tolerance of P. pratensis L. in this study; however, no synergistic effect between BC and AMF was observed. This finding contrasts with previous reports, which might be due to the contradictory regulation of Cd transport direction by BC and AMF.