Cadmium tolerance in soybean - a time course, concentration and varietal study

Eight varieties of Soybean commonly grown in Indiana were screened for Cadmium (Cd) tolerance. Two week old plants growing in a hydroponic solution under saturating fluorescent lighting (12:12-light:dark) were subjected to Cd Cl/sub 2/ solutions of 0, 10/sup -8/M, 10/sup -7/M and 10/sup -6/M concentrations. Symptomology was determined daily and representative plants were harvested after 1, 2, and 3 weeks of treatment. Harvested plants were rinsed, dissected, dried, digested and Cd levels determined by atomic absorption. Analysis of dry weight, shoot height, symptomology, and Cd levels in roots and shoots revealed varietal differences; the least to most effect on the varieties was: Amsoy, Beeson, Cutler, Bonus, Calland, Wayne, Wells and Williams. In the two extremes, Amsoy and Williams; Amsoy showed no dry weight or shoot length dimunution at 10/sup -6/M for three weeks whereas Williams at 10/sup -6/ for three weeks was 26% and 21% respectively compared to controls. Williams had 15 fold more Cd/g dry wt. in roots and shoots compared to Amsoy. Susceptible plant effects are directly related to Cd exposure time and concentration. If Cd enters roots it is transported to shoot.