Abstract Description

Arbuscular mycorrhizal (AM) fungi have been globally recognised for their plant growth and soil health promotion abilities. These obligate biotrophs have also been shown to be excellent plant stress alleviators. Heavy metal-contaminated soils are a global problem threatening ecosystems and human health. Mycorrhizal plants employ several mechanisms to detoxify or tolerate heavy metals, thereby improving plant growth potential. The Insizwa intrusion complex is a geological region in South Africa contributing to naturally occurring soils with high heavy metal concentrations. This study aimed to investigate the mycorrhizal status and diversity of AM fungi in these soils. Soil samples were collected from the eastern and western slopes of the Ngeli mountain, near Kokstad. Root samples were cleared, stained, and microscopically examined for mycorrhizal colonisation. Glomalin was extracted and subjected to a Bradford assay to quantify levels of Glomalin-related soil protein (GRSP). AM fungal diversity was assessed using culture-independent techniques. Colonisation ranged from 40 - 64 %, and concentrations of GRSP ranged from 0.942 to 3.210 mg/g soil, indicating the importance of AM fungal symbiosis in these high heavy metal soils. Glomerales were the dominant in these soils. Findings from this study could provide integral information on sustainable heavy metal bio-remediants that could be further developed for use in polluted soil environments, thereby benefiting various agricultural and horticultural industries that are adversely affected by soil heavy metal toxicity.