Phytotoxicity comparison of two invasive heracleum spp

Abstract

The biochemical interactions between species are referred as allelopathy and have an aspect of the broader field of chemical ecology. The bioactive materials involve both inhibitory and stimulatory biochemical interactions between organisms. Moreover, these compounds remain a significant for a complete understanding for plant responses in ecosystem. In general, secondary metabolites are widely accepted having a role in allelopathic interractions. Among the secondary metabolites phenolic compounds are the most common constituents in plants. These compounds also play important role in seed germination, plant development, growth, xylogenesis and flowering. Considering all above, we attempted to investigate into the phytotoxic effect of invasive H. sosnowskyi and H. montegazzum on seed germination. The phytotoxic effect of the total phenols content (TPC) and phytotoxic impact of H. sosnowskyi and H. montegazzum on perennial ryegrass (monocots) and winter rapeseed (dicots) seed germination was done ex situ. The phytotoxic effects of both Heracleum spp. aqueous extracts on the germination depended extract concentration (0.02-0.2%), plant parts (shoot: stem, leaf, blossom, seed; root) and growth stage (rosette-maturity). All parts of both H. sosnowskyi and H. montegazzum produced phenolics, which inhibited the acceptor-species seed germination. The phytotoxicity of H. sosnowskyi and H. montegazzum determined extracts were most phytotoxic at flowering stage due to highest TPC accumulation (30.42 and 89.16 mg mL-1 respectively).