A modified diatomite additive alleviates cadmium-induced oxidative stress in Bidens pilosa L. by altering soil microbial communities

In the present study, a modified silicon adsorbent (MDSA) was used as a passivator, and we explored the mechanism by which the MDSA helps B. pilosa L. alleviate Cd-induced oxidative stress and its effect on the rhizosphere microbial community. Therefore, a field study was conducted, and MDSA was applied at four levels (control (0 mg m^-2), A1 (100 mg m^-2), A2 (200 mg m^-2), and A3 (400 mg m^-2)). The application of MDSA significantly increased the soil pH and decreased the acid-soluble Cd content, which decreased by 30.3% with A3 addition. The addition of MDSA increased the relative abundance of Sordariomycetes due to the increased invertase activity and total nitrogen (TN) and total phosphorus (TP) contents, and the increased soil pH led to increased relative abundances of Alphaproteobacteria and Thermoleophilia. Meanwhile, MDSA addition significantly decreased the Cd concentrations in leaves and stems, which decreased by 19.7 to 39.5% in stems and 24.6 to 43.2% in leaves. All MDSA additions significantly decreased the translocation factor (TF) values of Cd, which decreased by 30.5% (A1), 50.9% (A2), and 52.7% (A3). Moreover, peroxidase (POD) from the antioxidant enzyme system and glutathione (GSH) from the nonenzymatic system played vital roles in scavenging reactive oxygen intermediates (ROIs) such as H₂O₂ and ⋅O₂^- in leaves, thereby helping B. pilosa L. alleviate Cd-induced oxidative stress and promote plant growth. Hence, our study indicated that MDSA application improved the rhizosphere soil environment, reconstructed the soil microbial community, helped B. pilosa L. alleviate Cd-induced oxidative stress, and promoted plant growth.