Effect of Arbuscular Mycorrhiza Fungus Diversispora eburnea Inoculation on Lolium perenne and Amorpha fruticosa Growth, Cadmium Uptake, and Soil Cadmium Speciation in Cadmium-Contaminated Soil

Cadmium (Cd) pollution has become aggravated during the past decades of industrialization, severely endangering human health through its entry into the food chain. While it is well understood that arbuscular mycorrhizal fungi (AMF) have a strong ability to regulate plant growth and Cd uptake, studies investigating how they affect soil Cd speciation and influence Cd uptake are limited. We designed a pot experiment comprising two AMF-inoculant groups (inoculation with Diversispora eburnea or no inoculation), three Cd concentration levels (0, 5, and 15 mg/kg), and two plant species (Lolium perenne and Amorpha fruticosa) to study the effect of AMF Diversispora eburnea on plant growth, Cd uptake, and Cd speciation in the soil. The results revealed that L. perenne exhibited higher productivity and greater Cd uptake than A. fruticosa, regardless of AMF D. eburnea inoculation. However, AMF D. eburnea significantly altered soil Cd speciation by increasing the proportion of exchangeable Cd and decreasing residual Cd, resulting in Cd enrichment in the plant root organs and the elimination of Cd from the polluted soils. Our experiments demonstrate that inoculating plants with AMF D. eburnea is an effective alternative strategy for remediating Cd-contaminated soil.