Seed germination inhibition by hogweed Heracleum sosnowskyi

Abstract

Assessment of the total phenols content (TPC) and biochemical impact of H. sosnowskyi on perennial ryegrass (monocots) and winter rapeseed (dicots) seed germination was carried out ex situ. Aqueous extracts of 2-yr. H. sosnowskyi exhibited higher phytotoxicity if compared with 1-yr. plant extracts. According to the results obtained, all parts of H. sosnowskyi produce phenolics, and thus inhibit acceptor-species seed germination. The character of phytotoxic impact of H. sosnowskyi aqueous extracts on the germination data significantly depended on plant age (1-year, 2-year), plant parts extracted (shoot; stem, leaf, blossom, seed; root), growth stage (rosette-ripening) and extract concentration (0.02-0.2%) (1). The most pronounced phytotoxicity of H. sosnowskyi was recorded at flowering stage due to highest TPC (30.42 mg ml"1). The results suggested that the invasive plant species may acquire spreading advantage in new territories by using 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 based on research in natural environment.