The beneficial role of indigenous arbuscular mycorrhizal fungi in phytoremediation of wetland plants and tolerance to metal stress

The potential of five plants namely Atriplex halimus L., A. canescens (Pursh) Nutt., Suaeda fruticosa (Forssk. ex J.F. Gmel.), Marrubium vulgare L. and Dittrichia viscosa (L.) Greuter from two selected wetlands in northwest Algeria subjected to house and industrial effluents were examined to assess their arbuscular mycorrhizal fungal (AMF) diversity and colonization, as well as to determine their tolerance and ability in accumulating metallic trace elements (MTEs). The purpose was to investigate whether, or not, these fungi are related to metallic uptake. Arbuscular mycorrhizal association was observed in all plant species, since the dual association between AMF and dark septate endophytes (DSE) was found in roots of 80% plants species. Hence, the decreasing trend of metal accumulation in most plant organs was Zn>Cu>Pb. and the most efficient species were M. vulgare> S. fruticosa> A. canescens> D. viscosa>A. halimus. The bioaccumulator factors exceeded the critical value (1.0) and the transport factors indicated that all these species were phytoremediators. Pearson correlation showed that Cd bioaccumulation and translocation were inhibited by AMF infection: meanwhile Zn, Pb and Cd accumulation were affected by AMF spore density and species richness, DSE frequency, pH, AMF and plant host. Native halophytes showed a multi-metallic resistance capacity in polluted wetlands. M. vulgare was the most efficient in metal accumulation and the best host for mycorrhizal fungi. AMF played a major role in metal accumulation and translocation.