Bioaugmentation-assisted phytoremediation of lead and salinity co-contaminated soil by Suaeda salsa and Trichoderma asperellum

Abstract

The combined application of plant Suaeda salsa and indigenous fungus Trichoderma asperellum on the treatment of a lead (Pb) and salinity (Na+ and Ca2+) co-contaminated soil was investigated by a flowerpot experiment. As demonstrated by plant growth and selected antioxidant parameters, S. salsa was able to tolerate and grow in the co-contaminated soil, especially bioaugmented with T. asperellum, which promoted plant growth (9–23% and 5–13% increases for plant height and fresh weight, respectively) and appeared to alleviate plant oxidative damage (7–85% and 7–49% decreases for plant malondialdehyde and peroxidase levels, respectively). The SDS-PAGE fingerprints indicated that the total protein contents of S. salsa were affected under Pb and salinity stresses. The interactions of Na+ and Ca2+ ions on the phytotoxicity of Pb remained hormesis phenomenon that low-dose alleviation and high-dose enhancement. The analysis of phytoextraction parameters and bioavailability demonstrated that Pb was mainly concentrated in plant roots and poorly translocated, indicating the phytostabilization served as a major repair pathway. On the contrary, the Na+ and Ca2+ ions were concentrated in plant by the following order: shoot > root. Moreover, bioaugmentation of planted soil with T. asperellum generally led to the 9–42%, 13–58%, and 19–30% decreases of plant Pb, Na+, and Ca2+ concentrations and translocations, respectively, as well as a 6–21% decrease of soil Pb bioavailability. This study provided a bioaugmentation-assisted phytoremediation technique to make up the deficiencies of the long-term remediation for heavy metals and salinity.