“…Studies on the uptake of heavy metals from culture solutions generally indicate that the metals accumulate far more in the roots than in the shoots, and that tolerant plants accumulate more metal in the roots than do non-tolerant plants (Peterson, 1975;Wu & Antonovics, 1975). In this way, less metal arrives at the shoots of tolerant plants than non-tolerant plants (Wu, Thurman & Bradshaw, 1975;Morishima & Oka, 1977;Baker, 1978). In Agrostis tenuis, zinc was found to be bound in the root cell wall, and the quantity of zinc bound correlated with the tolerance index of the plants (Turner, 1969(Turner, , 1970Peterson, 1969).…”