Limits of seed germination of phytomeliorants under conditions of heavy metals toxic concentrations

The aim of the study is to conduct biological testing at the initial stages of plant objects viability in the model conditions of heavy metal pollution. The paper presents the results of laboratory experiments to assess the impact of different concentrations of heavy metal salts on the viability of yellow melilot and great trefoil seeds. In the course of the conducted experimental studies the author has been established a direct dependence of the decrease in the indices of germination energy and laboratory germination of seeds with an increase in the concentration of phytotoxicant salts, determined the critical (threshold) concentration of the studied elements and the metal content, in which the processes of growth and development of seeds remain. The concentration of 0,01% cadmium, zinc, lead and copper was optimal for germination of melilot seeds, where germination was equal to 80%, 74%, 69% and 64%, respectively. For great trefoil seeds, high germination rates were noted in case of 0,01% contamination with lead, zinc, cadmium and copper - 82%, 80%, 77% and 76%, respectively, and in 0,1% salt solution of lead, copper and zinc there were recorded 75%, 74% and 72% of seedlings. Zinc in the concentration of 0,01% at the initial stages of germination of phytomeliorant seeds stimulated germination energy. The tendency of resistance to pollution by lead, zinc and copper was observed at sprouts of a great trefoil, and to pollution by cadmium the greatest resistance was shown by a melilot yellow. Defining the limits of the leguminous plant seeds germination in the presence of a toxic agent will allow research and development in respect of biological restoration of contaminated soils and can be used in technologically disturbed lands.