Enhancing mycophytoremediation potential of Chrysopogon zizanioides in chromite-asbestos mine waste soil using arbuscular mycorrhizal fungi: A natural bioaccelerator for soil ecosystem rehabilitation

Abstract

Soil contamination with toxic elements (TEs) has become a serious environmental issue in recent decades. Bio-based approaches especially, "phytoremediation-associated with arbuscular mycorrhizal fungi (AMF)" has emerged as a promising, eco-friendly and sustainable technology worldwide. The present investigation assessed the impact of AMF on the growth and TEs accumulation abilities of vetiver (Chrysopogon zizanioides) in a soil containing chromite-asbestos mine wastes. Among the four different AMF species tested-Glomus hoi, Funneliformis coronatum, Claroideoglomus claroideum, and Claroideoglomus etunicatum-Glomus hoi (M1) showed high efficiency in improving soil quality, mitigating TEs stress and promoting healthy plant growth. In comparison with control plant (devoid of AMF), the higher accumulation of TEs in the roots (Ni: 27.44 %, Cr: 21.74 %) was observed in presence of Glomus hoi and TEs concentration in soil was reduced in bioavailable phase. A periodic increase in microbial-enzymatic activity was found across all AMF inoculums, with the M1 treatment (microbial biomass carbon: 527.66 mg kg^-1) exhibiting highest microbial activity as compared with control. The AMF infection resulted in heightened antioxidant activity, which mitigated TE-induced stress in vetiver plants. Additionally, glomalin production (TG: 2.59 folds), phosphorus uptake and colonization percentage were higher in the vetiver plant inoculated with Glomus hoi compared to the other AMF species. The model-based analysis (PLS-SEM and sobol model) also validates these findings, showing that the presence of AMF enhances phytoremediation efficiency. Overall, this study highlighted that the application of appropriate AMF species can enhance mycophytoremediation potential and provide a viable approach for the rehabilitation of mine-degraded soils.

Keywords: Chromite-asbestos mine waste; Glomalin; Mycophytoremediation; PLS-SEM; Sobol analysis.