| Abstrakt: |
The essential oils from oregano (Origanum syriacum L.) and laurel (Laurus nobilis L.), and their main components, namely, carvacrol, 1,8-cineole and a- pinene, were tested to determine their inhibitory effects on the seed germinations of three different weeds [redroot amaranth (Amaranthus retroflexus L.), wild licorice (Glycyrrhiza glabra L.), curled dock (Rumex crispus L.) and cutleaf ground-cherry (Physalis angulata L.)] and three crops [(wheat (Triticum aestivum L.), corn (Zea mays L.) and cotton (Gossypium hirsitum L.)]. Gas chromatography/mass spectroscopy (GC-MS) analysis showed that 1,8-cineole and carvacrol were the major components of laurel and oregano essential oils, respectively. An in-vitro bioassay seed germination test showed that oregano essential oil and carvacrol completely inhibited the germination of weeds at all the concentrations ranging from 1 to 5 μl/Petri dish, while seed germination of test weeds significantly decreased with increasing of the concentrations of laurel essential oil and its main components, 1,8-cineol and α-pinene ranging from 5 to 20 μl/Petri dish. Oregano essential oil and carvacrol were totally ineffective on cotton and corn germination (except for the concentration of 5 μl/Petri dish of cavracrol), whereas they had a strong inhibitory activity against wheat seeds. On the other hand, the laurel essential oil and its main component, 1,8-cineole, showed less selective action on test crop species. It could be concluded that volatile oil from O. syriacum and its main component, cavracrol, possessed a strong inhibitory effect on germination of the weeds and was totally selective action on some crops, and could be utilized as bioherbicide for future weed management programmes. [ABSTRACT FROM AUTHOR] |
