Comparison of root colonization by arbuscular mycorrhizal fungi in energy crop species cultivated on arable land contaminated with heavy metals

Arbuscular mycorrhiza is a widespread terrestrial symbiosis, involving 80 - 85% of vascular plants in almost all ecosystems. AM fungi increase plant tolerance to heavy metals by developing mechanisms allowing immobilization metals within or near the root and preventing their translocation to the shoot. Therefore, AMF could be involved in phytostabilization of heavy metals contaminated soils. The aim of the presented study was to explore the effect of heavy metals on arbuscular mycorrhizal fungi (AMF) root colonization of selected energy crop species: Miscanthus x giganteus, Panicum virgatum and Spartina pectinata cultivated on heavy metals contaminated arable land under different fertilisation (NPK vs. microbial inoculation). All examined plant species formed arbuscular mycorrhizal associations and differences in degree of mycorrhizal colonization among experimental variants were found. Influence of soil fertilization on AMF root colonization wasspecies-dependent. Both NPK fertilization and microbial inoculation resulted in reduction of mycorrhizal colonization in Miscanthus x giganteus, whereas in Panicum virgatum degree of AMF root colonisation was increased. Soil fertilisation had no effect on degree of Spartina pectinata root mycorrhization, sincethey were almost fully colonized independly on fertilization. In conclusions, contamination with heavy metals did not result in restriction of mycorrhizal colonization, which could be a consequence of AMF adaptation to such conditions. Nevertheless, among tested species, higher level of mycorrhizal colonization was found for Spartina pectinata roots. It indicates the highest susceptibility of this species to development of mycorrhizal structures regardless of heavy metal pollution and fertilization.