For cost effective phyto-extraction, it is essential to create stabilizing plants which produce high levels of root and shoot biomass, high tolerance and resistance for heavy metals. This can be done by mycorrhizal association.

Mycorrhizal association: It is a symbiotic association between a fungus and the roots of a plant. The fungus colonizes the host plants’ roots, either intracellularly or extracellularly. This mutualistic association provides the fungus with relatively constant and direct access to carbohydrates, such as glucose and sucrose supplied by the plant. The carbohydrates are translocated from their source (usually leaves) to root tissue and on to fungal partners. In return, the plant gains the benefits of the mycelium’s higher absorptive capacity for water and mineral nutrients (due to comparatively large surface area of mycelium: root ratio), thus improving the plant’s mineral absorption capabilities. These fungi have a protective role for plants rooted in soils with high metal concentrations. The trees inoculated with fungi displayed high tolerance to the prevailing contaminant, survivorship and growth in several contaminated sites. This was probably due to binding of the metal to the extramatricial mycelium of the fungus, without affecting the exchange of beneficial substances.

So, Mycorrhizal Association enhances plant growth on severely disturbed sites, including those contaminated with heavy metals and plays an important role in metal tolerance and accumulation [34, 35].