Objective  To explore the effects of arbuscular mycorrhizal (AM) fungal inoculation on the growth of Nitraria sibirica Pall. under different levels of salt and heavy metal stress, and provide a scientific basis and data support for plant-microbial joint remediation of heavy metal contaminated and salinized soil.

Method  Greenhouse potted soil was used to simulate different levels of heavy metal Cd polluted (0, 2, 5 mg·kg⁻¹ Cd in dry soil) and NaCl (0, 1.5 g·kg⁻¹ Na⁺ in dry soil) salinized soil (Cd0Na0, Cd0Na1.5, Cd2Na0, Cd2Na1.5, Cd5Na0, Cd5Na1.5). The effects of AM fungi (Funneliformis mosseae) on mycorrhizal infection, element absorption, ion balance, biomass, Na⁺ and Cd contents of N. sibirica under Cd and NaCl stress were studied.

Result  Under heavy metal Cd and NaCl stress, the mycorrhizal infection rate of F. mosseae roots was 12.68%−21.90%. Compared with CK with no inoculation, AM inoculation increased the total dry weight of N. sibirica in different treatments by 101.35%−215.29%. The aboveground mineral nutrient elements significantly increased by 47.55%−216.50%. Na⁺ contents in shoots and roots decreased significantly, while Na⁺ accumulation in root increased significantly. Cd contents in shoots treated with Cd2Na0, Cd2Na1.5, Cd5Na0 and Cd5Na1.5 and roots treated with Cd2Na1.5, Cd5Na0 and Cd5Na1.5 significantly decreased. At the same time, K⁺/Na⁺, Ca²⁺/Na⁺ and P⁵⁺/Na⁺ ionic equilibrium in shoots and roots were adjusted after AM inoculation.

Conclusion  AM fungi can alleviate the adverse effects of NaCl and heavy metal stress on the growth of N. sibirica by promoting the absorptions of nutrient elements, regulating the ion balance in the plant and affecting the absorptions of Na⁺ and Cd.