Synthetic herbicides have harmful effects on the environment and human health. Therefore, the establishment of natural products with herbicidal activity is very important. The first step of selecting products with a herbicidal effect is to evaluate their inhibitory activity on seed germination. Methanolic extracts, acetone exudates and essential oils of 13 plant species were assayed as germination inhibitors against Lolium perenne L., Trifolium repens L. and Trifolium pratense L. Among the tested samples the essential oils of Origanum vulgare subsp. hirtum (Link) Ietsw. and Thymus moesiacus Velen., showed the most significant germination inhibitory activity on all tested weeds. Methanolic extract of Narcissus pseudonarcissus cv. Carlton and essential oils of Thymus longidentatus (Degen & Urum.) Ronniger and Micromeria dalmatica Benth. showed also strong inhibitory activity but it is species-specific. Chemical composition of the active essential oils and extract were analyzed by GC/MS. The main components of the essential oils were identified as carvacrol, citral isomers, α-terpinyl acetate, piperitone oxide, β‑pinene. In the methanolic extracts of the aerial parts of N. pseudonarcissus phenolic and organic acids, alkaloids and carbohydrates were identified. The received results showed that the studied species produce compounds with strong herbicide activity and can be used for production of bioherbicides.
Key words: Origanum vulgare subsp. hirtum , Thymus sp. , Micromeria dalmatica , Narcissus pseudonarcissus , herbicidal activity
Topic: BIOLOGY