INITIAL GROWTH OF PHLEUM PRATENSE UNDER THE INFLUENCE OF LEAF WATER EXTRACTS FROM SELECTED GRASS SPECIES AND THE SAME EXTRACTS IMPROVED WITH MgSO4⋅7H2O

In multi-species grassland communities, plant growth and development are modified by both a number of habitat-related factors and physico-chemical processes resulting from the neighbourhood of other species. Plant interactions mediated through chemical substan-ces are identified within the allelopathic processes. The allelopathic process involves excre-tion of bioactive compounds from plant or microorganisms that inhibit or stimulate physio-logical processes of the neighbour plants. The allelopathic compounds can exert a harmful impact on the emergence of seedlings, initial development and installation. Therefore, it is essential to reduce the allelopathic influence of the old sward on the plants sown as well to limit the interaction between these new plants. It is claimed that, among others, fertili-zer components may partially reduce effects of allelopathic influences In this study we show the differences in growth inhibition of Ph. pratense seedlings caused by the water extracts of leaves of selected grass species and the amelioration of growth inhibition by addition of magnesium sulfate. The bioassays were performed on Petri dishes under the laboratory conditions. The activity of allelopathic substances in th