Vesicular-arbuscular mycorrhizae decrease zinc-toxicity to grasses growing in zinc-polluted soil

Vesicular-arbuscular mycorrhizae (VAM) are known to enhance the uptake of heavy metals in the host and could therefore increase the effects of heavy metal pollution on plant populations. The effect of mycorrhizal infection on two grasses occurring in coastal dunes downwind of a blast furnace complex and which are becoming increasingly polluted, was examined. In a 2 × 2 factorial experiment, the effects of VAM and zinc on the growth and mineral nutrition of Festuca rubra and Calamagrostis epigejos was established. It appeared that VAM infection alleviated the negative effect of zinc on growth in both species. Although both zinc and VAM influenced the uptake and translocation of various minerals, differences in mineral concentrations could not explain why a higher biomass is produced by grasses infected with mycorrhiza in zinc-polluted soil.