Accumulation and phytotoxicity of secondary metabolites in invasive Heracleum sosnovskyi Manden

Increasing human activity has resulted in a concomitant increase of alien Heracleum sosnovskyi Manden migration and spread into new habitats suppressing native species due to giant size, and biochemical activity. The preliminary bioassay ex situ showed different phytotoxicity of 1 and 2-year old plant extracts due to variation in accumulated phenolics content. The extracts inhibited seed germination and the level of inhibition was concentration- dependent. Phenolics contents vary throughout the plant age (0.22–81.03 mg ml –1 ), growth stage (0.17–81.03 mg ml -1 ) and across different plant parts (2.97–92.61 mg ml –1 ) inhibiting the acceptors plants germination. The results suggested that invasive H. sosnovskyi possesses allelopathic activity therefore may acquire spreading advantage in new territories throughout use of allelochemicals. Nonetheless, species evidence for allelopathic effects should also include research in situ .