To rank the contributions of roots and shoots to Cd uptake by the hyperaccumulator Noccaea caerulescens, two hypotheses were tested: Shoots control the uptake through detoxification reactions; alternatively, roots do this through absorption and translocation. In a first experiment, plants with the same final age were exposed for 1, 2 or 3 weeks to 0.5 μM Cd in hydroponics. In another experiment, either roots or shoots or both were pruned before the plants were exposed for 1 week to Cd at 0.5 μM in the nutrient solution. The first experiment showed that the Cd accumulation was driven by the root absorption combined with xylem loading, keeping the root Cd concentration constant. After root or/and shoot pruning, all the plants accumulated the same total quantity of Cd. After root pruning, the remaining roots increased their Cd absorption influx. Shoot pruning alone did not affect absorption or storage in roots and the pruned shoots accumulated as much Cd as the unpruned ones. Similar results were obtained for all major and minor nutrients. Root absorption and xylem loading are the major processes controlling Cd hyperaccumulation in N. caerulescens, the shoot being a compartment in which the metal exported by the roots is stored.Read less <