The phenomenon which takes place in the phytoremediation process of soils polluted with heavy metals is very difficult to be understood, due to complexity of dynamics in rizosphere zone, An important parameter for analysis of metal quantity accumulated in plant tissue is the bioconcentration factor (BCF) and is calculated either for a part of the plant, or fot the whole plat using the formula: BCF soil-plant = Qm / Qs, (quantity of metal accumulated in plant, mg/kg d.m. ratio to total concentration of metal from soil mg/kg d. m.). Correlating the metal concentration from soil/plant with BCF shows that the studied plants have affinity for metals in the following order Zn>Mn>Cu. On the other hand, plants demonstrate tolerance to Fe presence of 50-60 mg/kg d. m. Its accumulation is restricted through a mechanism specific to plants on values of 102 times lower the the quantity in the soil. By using of volcanic tuff as amendments, level of metals accumulation in plants is changed.
In this paper we wanted to determine the influence of phosphorus and nitrates in the development of Lemna minor L. To achieve this purpose, eight different growth variants were proposed, starting from the Hoagland culture medium, where the concentration of these two compounds varied. The growth rate in the eight experimental variants, ranges between 150% -325%, with a minimum in the control sample and a maximum at the highest concentration of phosphorus in water.