The soil in the north-east of Belgium is contaminated with heavy metals (Zi en Cd) on a large scale. Phytoremediation (use of green plants for metal accumulation, e.g. poplars) would be a possible solution. The target of this project is to find an ideal combination of poplar and plant-associated bacteria for the optimal biomass production and phyto-extraction of Cd and Zi. More specifically more knowledge is wanted and manipulation of the bacterial society (Rhizosphere and endophytic) associated with the poplar.