CADMIUM UPTAKE BY LETTUCE VARIETIES

The uptake of cadmium (Cd) by lettuce (Lactuca sativa L.) varieties was studied in a soil and water culture experiment. In the soil experiment, sandy soils from both a Cd-contaminated and a non-contaminated area were used, whereas the water culture experiment included three Cd levels (0, 0.03 and 0.1 mg l-1). Fresh and dry yields of shoots and roots were hardly affected by Cd in both experiments. The lettuce varieties showed a close similarity in shoot Cd concentration, ranging from 8.23 to 10.72-mu-g g-1 DW for the Cd-contaminated soil and from 3.96 to 8.83-mu-g g-1 DW in the water culture at the highest Cd level tested. These results are contradictory to published data on large genotypic variation of Cd concentration in lettuce. Based on the narrow range in shoot (and root) Cd concentration among varieties, it is unwarranted to use lettuce as a pilot plant in comparative physiological investigations on Cd uptake and distribution.