DIFFERENTIAL EFFECTS OF CADMIUM ON LETTUCE VARIETIES

Continuing studies towards fining means of reducing the potentially hazardous dietary intake of excessive Cd via food crops involved a solution culture experiment wherein 9 varieties of lettuce [Lactuca sativa var. capitata, L. sativa var. crispa, L. sativa var. longifolia] were subjected to various substrate Cd concentrations. Differential tolerance of varieties to phytotoxicity was not readily visible but a significant interaction of substrate Cd and variety was obtained for dry matter yields. Significant interactions indicated that response of tissue Cd concentration, total plant Cd uptake and translocation of Cd to the edible leaf portion were dependent on variety as well as substrate Cd. Evidence that Cd uptake and translocation are genetically controlled warrants the selection of varieties that assimilate the least Cd and translocate the least to the plant part used for human or animal consumption.