Mycorrhiza-assisted phytoremediation of spiked chromium-contaminated soil: Assessing AMF-vetiver symbiosis for Cr accumulation and soil quality enhancement

Chromium (Cr) is a hazardous pollutant in industrial and mining areas and threatens soil ecosystems. Mycorrhiza-assisted phytoremediation serves as an eco-friendly and effective approach to mitigate Cr contamination from soil. In this investigation, varying Cr dosages (100 mg kg⁻¹, 500 mg kg⁻¹, and 1000 mg kg⁻¹) were applied into the soil alongside vetiver plants (Chrysopogon zizanioides L.) inoculated with three different AMF species (Claroideoglomus claroideum, Glomus hoi, and Claroideoglomus etunicatum). The results indicated that AMF inoculation enhanced Cr accumulation (1.96 folds, 1.63 folds) in the root tissue of vetiver compared to the control. Among the AMF species, Glomus hoi demonstrated the highest effectiveness in reducing Cr bioavailability (P10: 0.247 mg kg⁻¹, P11: 1.117 mg kg⁻¹, and P12: 4.789 mg kg⁻¹) in the soil, followed by Claroideoglomus claroideum and Claroideoglomus etunicatum at post-harvest. Additionally, microbial and enzymatic activity improved in the presence of AMF compared to the control, as AMF alleviated Cr-induced stress by stimulating antioxidant activity. AMF enhanced soil glomalin-related proteins and colonization percentage, thereby promoting plant growth. The correlation and principal component analysis depict a positive association between Cr accumulation in vetiver (root and shoot) and the different Cr phases. Interestingly, in the presence of Glomus hoi, the VTF (<1) and VBCF (>1) indicate that this symbiotic association is well-suited for phytoremediation applications. Hence, AMF-assisted phytoremediation emerges as a viable and sustainable approach, offering advantages over other remediation techniques and providing potential solutions for managing soil Cr contamination.