Phytotoxicity of zinc, nickel, cadmium, lead, copper and chromium in three pasture plant species supplied with graduated amounts from the soil

Abstract

Narrow-leaved plantain, white clover and perennial ryegrass were grown on an acid sandy soil with added levels of Zn, Ni, Cd, Pb, Cu and Cr, as the single test elements. The metals were classified for inhibitive metal concentrations in the shoots of the plants and in the soil. Ni, Cd and Cu were found to cover a fivefold range with one exception: Cd in plantain was inhibitive at a tenfold higher tissue concentration than in clover and grass. Zn was more efficiently absorbed, but tolerated at a higher soil concentration because it was much less toxic to the tissue. Cr was tolerated at low shoot concentrations but at high concentrations in the soil because its uptake by the shoots was disproportionally smaller. Differences between plant species in response to the soil test levels were illustrated in terms of relative uptakes and shoot concentrations for toxicity.