GENETIC LINE EFFECTS ON PARAMETERS INFLUENCING CADMIUM CONCENTRATION IN LETTUCE (LACTUCA-SATIVA L)

Cd uptake rates, translocation percentages, and shoot:root ratios were determined for 4 lettuce lines known to concentrate different levels of leaf Cd. Uptake rates were measured for one hr on 14-day-old plants exposed to Cd concentrations ranging from 2.5 to 100.00 nM. PI 278080, the high Cd line, had the highest uptake rate; PI 140398 and PI 169493, 2 low-Cd lines, had intermediate uptake rates; and 'Ruby', a low-to-intermediate line, had the lowest overall uptake rate. Translocation percentages and shoot:root ratios were measured from one to 7 days on 15- to 21-day-old seedlings grown at 0.4-mu-M Cd. PI 278080 and 'Ruby' translocated about 40% of absorbed Cd to shoots, whereas PI 140398 and PI 169493 translocated about 30%. The shoot:root ratios of PI 278080, PI 140398 and PI 169493 ranged from 2.5 to 2.7, and these values were significantly lower than the ratio of 3.4 for 'Ruby'.