Phytoremediation of cadmium-contaminated wetland soil with Typha latifolia L. and the underlying mechanisms involved in the heavy-metal uptake and removal.

The effects of Typha latifolia L. on the remediation of cadmium (Cd) in wetland soil were studied using greenhouse pot culture, with soil Cd concentrations of 0, 1, and 30 mg/kg. The T. latifolia showed excellent tolerance to the low and high concentrations of Cd in soil. A higher bioaccumulation of Cd was observed in roots, with bioconcentration factor values of 51.6 and 9.30 at 1 and 30 mg/kg of Cd stress, respectively; Cd concentration in T. latifolia was 77.0 and 410.7 mg/kg, and Cd content was 0.11 and 0.22 mg/plant at the end of the test period. The soil enzyme activities (urease, alkaline phosphatase, and dehydrogenase) exposed to 0, 1, and 30 mg/kg Cd were measured after 0-, 30-, 60-, and 90-day cultivation period and showed an increasing trend with exposure time. Metabolite changes were analyzed using liquid chromatography-mass spectrometry, combined with principal component analysis and orthogonal partial least squares discrimination analysis. Among 102 metabolites, 21 compounds were found and identified, in response to treatment of T. latifolia with different Cd concentrations. The results showed that T. latifolia had a good remedial effect on Cd-contaminated soil. The metabolites of T. latifolia changed with different Cd concentration exposures, as a result of metabolic response of plants to Cd-contaminated soils. Analysis of metabolites could better reveal the pollution remediation mechanism involved in different Cd uptake and accumulate properties.