Inhibitory effects of invasive Heracleum sosnowskyi on rapeseed and ryegrass germination

Assessment of the total phenols content (TPC) and biochemical impact of H. sosnowskyi on perennial ryegrass (monocots) and winter rapeseed (dicots) seed germination was done ex situ. Aqueous extracts of 2-yr old H. sosnowslyi exhibited higher phytotoxicity than 1-yr. old plant extracts. The phytotoxic effects of H. sosnowskyi aqueous extracts on the germination depended extract concentration (0.02- 0.2%), plant age (1-year, 2-year), plant parts (shoot: stem, leaf, blossom, seed; root) and growth stage (rosette-ripening). The phytotoxicity of H. sosnowskyi determined extract was most strong at flowering stage due to highest TPC (30.42 mg ml-1). All parts of H. sosnowskyi produced phenolics, which inhibited the acceptor-species seed germination. The results suggested that invasive plant species may acquire spreading advantage in new territories through use of their allelochemicals to inhibit germination. Nonetheless, species evidence for allelopathic effects should not be restricted to analysis of the plant extracts in the lab, but also include research in natural environmentVytauto Didžiojo universitetasŽemės ūkio akademij