Decreased incidence of mycorrhizal root tips associated with soil heavy-metal enrichment

Mycorrhizal incidence was studied at two forested locations in south-central Virgina. At each location, one site with soil naturally enriched in copper, lead and zinc was designated as mineralized, and an adjacent site, with significantly lower levels of these metals, was used as a control. A total of 223 soil samples were collected during the summer of 1984 and assayed for active mycorrhizal tips. A reduced active mycorrhizal root tip count was found in those samples collected from the mineralized sites at both locations (P≤0.001).