AM fungi make Cyamopsis tetragonaloba L. Taub. tolerant to heavy metal soil pollution

The effect of arbuscular-mycorrhiza on uptake and translocation of heavy metals by guar (Cyamopsis tetragonaloba L. Taub.) was investigated in soil contaminated by low and high concentrations of heavy metals viz, Zn, Cu, Cd and Ni. The plants were inoculated with four different AM fungi viz., Acaulospora denticulata, Gigaspora albida, Glomus albidum and Sclerocystis sinuosa. AM colonization was not affected by lower metal concentrations and it was observed up to 77% with a G. albida + 1/2 dose of Zn. High soil concentrations of Ni and Cd reduced percentage of root colonization and dry biomass of guar plants. Mycorrhizal plants grew better but growth of mycorrhizal guar plants in heavy metal toxicated soil remained equal to those of uninoculated, non-contaminated control. Accumulation of heavy metals was higher in roots than in leaves. These results indicate the possibilities of using mycorrhizal fungi for extraction of heavy metals from polluted soil which were retained in the fungal structures and restricts subsequent metal transfer to host plant.