Modulation by arbuscular mycorrhizal fungi on biochar - Phragmites australis system in P-deficient environment: Cd...

This study addresses the challenge of low phytoremediation efficiency caused by nutrient deficiency by evaluating abiotic and biotic-abiotic enhancement strategies. Specifically, we examine the potential of biochar (BC) alone and in combination with arbuscular mycorrhizal fungi (BCA) to improve cadmium (Cd) phytoremediation under phosphorus-deficient conditions. The results demonstrate that both BC and BCA enhance Cd resistance and accumulation in Phragmites australis through shared mechanisms, including improved rhizosphere nutrient availability and increased proline accumulation. However, BC primarily reduces oxidative stress by lowering the metal burden, while BCA more effectively mitigates oxidative stress by activating antioxidant enzymes. BC-induced rhizosphere Cd passivation and stem Cd retention significantly promoted plant growth, increasing biomass and Cd accumulation by 299 % and 378 %, respectively, under high-Cd conditions. BCA eliminated the Cd passivation and retention effects of BC and modulated root functional groups to facilitate Cd translocation to the shoots. Consequently, shoot Cd concentrations in the BCA treatments were 3.18 and 2.46 times higher than in the control and BC treatments, respectively, under high-Cd conditions. The effects of BC and BCA under phosphorus-deficient conditions provide novel strategies for expanding phytoremediation applications, demonstrating their potential to improve remediation efficiency in nutrient-deficient environments.