Effect of Funneliformis mosseae on the growth, cadmium accumulation and antioxidant activities of Solanum nigrum

• Funneliformis mosseae (Fm) colonized Solanum nigrum very well in the Cd-added soils.
• Fm symbiosis significantly promoted the P acquisition and the growth of S. nigrum.
• Fm colonization increased Cd concentrations and Cd uptakes in the shoots and roots.
• Fm inoculation improved CAT, POD and APX activities in the leaves of S. nigrum.

Arbuscular mycorrhizal (AM) fungi can promote plant growth and resistance to heavy metal (HM), affect HM bioavailability and uptake by plants, and thus have been considered as the most prominent symbiotic fungi for contribution to phytoremediation. A greenhouse pot experiment was performed to assess the effects of Funneliformis mosseae BGC XJ02 (Fm) on the plant growth, P acquisition, Cd accumulation, phytochelatins (PCs) production and antioxidant activities of Cd-hyperaccumulator Solanum nigrum in different Cd-added soils (0, 5, 10, 20 and 40 mg Cd kg−1 soil). Fm associated with S. nigrum very well, and mycorrhizal colonizations were not influenced by Cd addition. Fm inoculation significantly increased P acquisition, plant growth, Cd concentration and Cd uptake in both shoots and roots of S. nigrum at all Cd levels. The improvement of catalase (CAT), ascorbate peroxidase (APX) and peroxidase (POD) activities in the leaves of mycorrhizal plants suggested that Fm colonization helped S. nigrum to relieve oxidative damage to biomolecules in Cd-contaminated soil. Moreover, glutathione reductase (GR) activities in the leaves of mycorrhizal plants were elevated (from 17% to 99%) in lower Cd levels (0, 5 and 10 mg Cd kg−1 soil), but reduced in higher Cd levels (20 and 40 mg Cd kg−1 soil). The obvious decrease of malonaldehyde (MDA) content in the leaves of mycorrhizal plants displayed that Fm symbiosis significantly enhanced antioxidant activities. In conclusion, Fm symbiosis alleviated Cd phytotoxicity to S. nigrum through the improvement of P acquisition and activities of CAT, POD, APX in mycorrhizal plants, and then improved plant growth and phytoremediation efficiency for Cd-contaminated soil.