Arbuscular mycorrhizal fungi (AMF) play key roles in enhancing plant tolerance to heavy metals, and iron (Fe) compounds can reduce the bioavailability of arsenic (As) in soil, thereby alleviating As toxicity. However, there have been limited studies of the synergistic antioxidant mechanisms of AMF (Funneliformis mosseae) and Fe compounds in the alleviation of As toxicity on leaves of maize (Zea mays L.) with low and moderate As contamination. In this study, a pot experiment was conducted with different concentrations of As (0, 25, 50 mgꞏkg⁻¹) and Fe (0, 50 mgꞏkg⁻¹) and AMF treatments. Results showed that under low and moderate As concentrations (As25 and As50), the co-inoculation of AMF and Fe compound significantly increased the biomass of maize stems and roots, phosphorus (P) concentration, and P-to-As uptake ratio. Moreover, the co-inoculation of AMF and Fe compound addition significantly reduced the As concentration in stem and root, malondialdehyde (MDA) content in leaf, and soluble protein and non-protein thiol (NPT) contents in leaf of maize under As25 and As50 treatments. In addition, co-inoculation with AMF and Fe compound addition significantly increased the activities of catalase (CAT), peroxidase (POD), and superoxide dismutase (SOD) in the leaves of maize under As25 treatment. Correlation analysis showed that stem biomass and leaf MDA content were very significantly negatively correlated with stem As content, respectively. In conclusion, the results indicated that the co-inoculation of AMF and Fe compound addition can inhibit As uptake and promote P uptake by maize under low and moderate As contamination, thereby mitigating the lipid peroxidation on maize leaves and reducing As toxicity by enhancing the activities of antioxidant enzymes under low As contamination. These findings provide a theoretical basis for the application of AMF and Fe compounds in the restoration of cropland soil contaminated with low and moderate As.

To explore the potential of Koenigia mollis as a pioneer plant in acid tin mine wasteland, Koenigia mollis plants and the corresponding rhizosphere soils in different areas in Lianghe County, Yunnan Province were collected, and their chemical properties and heavy metals contents were determined., the adaptability of the plant to the barren tailing environment and its acid resistance and tolerance to heavy metal such as Cu (Cu, CAS. No. 7144-37-8), Cd (Cd, CAS. No. 7440-43-9) and Pb (Pb, CAS. No. 10099-74-8) pollution were analyzed. Results showed that Koenigia mollis growth was normal. The pH value in rhizosphere soils was 3.74–4.30, which was strongly acidic. The organic matter (OM), total nitrogen (TN) (N, CAS. No. 7727-37-9), available potassium (AK) (K, CAS. No. 7440-09-7), and available phosphorus (AP) (P, CAS. No. 7723-14-0) contents in soils of the research area were in low levels. The total contents of Cu, Cd, and Pb in the soil of the research area exceeded the pollution risk screening value for the national risk control standard of soil environmental quality, indicating that Koenigia mollis has a certain resistance to acid and heavy metal pollution. In addition, Koenigia mollis has strong transport and enrichment capacity for Cu, Cd, and Pb and therefore has potential as a pioneer phytoremediation plant for acid tin mine wastelands and a remediated plant for agricultural land around metal mining areas.

The extensive stockpiling of phosphogypsum(PG) poses significant environmental challenges, while many agricultural soils in Yunnan Province exhibit sulfur