Spatial variation in 109Cd accumulation in roots of durum wheat seedlings. Time-course of 109Cd accumulation in root tips (1 cm) and basal root sections of high (TL-H) and low (TL-L) Cd-accumulating isolines of durum wheat. Intact roots of 6-d old seedlings were exposed for up to 180 min in 15 mL of complete nutrient solution containing 50 pM 109Cd. Roots were desorbed for 30 min (2°C) prior to harvest in non-radiolabelled nutrient solution containing 50 μM DTPA. The 3 longest roots per plant were separated into root tips and remaining basal portions. Means and standard errors of 3 replicates (5 plants per replicate) are plotted.