Augmentation with potential endophytes enhances phytostabilization of Cr in contaminated soil

Abstract

The contamination of soil with heavy metals is a major environmental problem worldwide. The combined use of plants and their associated microbes has gained popularity in recent years for their potential to remediate heavy metal-contaminated soil. In the current study, the effect that augmentation of soil with plant growth-promoting endophytes has on the phytostabilization of chromium (Cr)-contaminated soil was investigated. Three potential endophytic bacterial strains (Enterobacter sp. HU38, Microbacterium arborescens HU33, and Pantoea stewartii ASI11) were inoculated individually as well as in combination to Leptochloa fusca and Brachiaria mutica vegetated in Cr-contaminated soil. The accumulation of Cr in the root and shoot of the plants was determined. Moreover, bacterial persistence in the rhizosphere and endosphere was determined. Augmentation with potential endophytes significantly increased root length (24-45%), shoot height (39-64%), chlorophyll content (20-55%), and the overall biomass (32-61%) of the plants. Although L. fusca and B. mutica showed potential to accumulate Cr in their root and shoot, endophytic augmentation increased uptake, translocation, and accumulation of Cr in the roots and shoots of both plant species. However, L. fusca showed more potential to phytostabilize Cr as compared to B. mutica. Furthermore, the potential endophytes showed more survival and persistence within the roots than in the rhizosphere and shoot interior. This study provides useful evidence of endophyte-assisted phytoremediation to be the most sustainable and affordable approach for in situ remediation of Cr-contaminated soil.

Enhanced remediation of Cr6+ in bacterial‐assisted floating wetlands

“…Accordingly, high BCF values for roots confirm the plant phytostabilization potential and Cr immobilization in the vacuoles of root cells (Ullah et al , 2015). Similar observations are reported in other studies where plant‐bacteria partnership is employed for the removal of Cr from contaminated soils (Khan et al , 2015; Ahsan et al ., 2018).…”

“…Nevertheless, Cr accumulation in the roots can be correlated with the combined application of plant and bacteria that offers a series of ecological services, that is, microbial reduction, sequestration, chelation, phytostabilization, biotransformation, bioaccumulation, etc. (Ahsan et al ., 2018).…”

Halophytic Grasses, a New Source of Nutraceuticals? A Review on Their Secondary Metabolites and Biological Activities

“…Due to their important ecological role related to the ability to cope with high concentrations of toxic ions as well as to the capacity to accumulate heavy metals present in the environment [12], studies have been dedicated to their potential as stabilizers and/or phytoextractors of heavy metal polluted soils [12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40]. Nonetheless, their phytochemistry and biological activities have not been equally well investigated.…”