Origanum onites L. uçucu yağının kimyasal bileşenleri ve allelopatik etkisi

Abstract

In this study, chemical composition and allelopathic effect of essential oil obtained from ground parts (shoots+leaves+flowers) of Origanum onites L. plant on seed germination and seedling growth of different plant species were investigated. Essential oil was obtained with the use of the hydro-distillation method from O. onites plant collected from Mersin province. It was identified 24 different compounds by GC/MS analysis in O. onites essential oil, while the main compounds were determined as carvacrol (59.87%), γ-terpinene (17.08%) and β-cymene (8.83%). The allelopathic effect of the essential oil, two layers of filter paper were placed bottom of 9 cm diameter disposable Petri dishes then seeds of Amaranthus retroflexus L., Triticum aestivum L. and Lepidium sativum L. were homogeneously distributed on filter paper. Filter papers were thoroughly moistened using distilled water. The filter paper was glued to the center of the lid of each Petri dish. The different concentrations (0, 0.5, 1, 1.5, 5, 15 μl/Petri dishes) of the essential oil were applied to the filter paper pieces. Then lid of each Petri dish was closed and sealed with Parafilm. Petri dishes were incubation at 12 h dark-12 h light periods with an average temperature of 24±1 oC for 1-4 weeks. At the end of incubation period, germination rates, root and shoot lengths of the test plants were determined. The 15 μl/Petri concentration of O. onites essential oil were completely inhibited seed germination, root and shoot growth of A. retroflexus L., T. aestivum L. and L. sativum L. plants. A. retroflexus L. was found to be more sensitive to essential oil. The results show that O. onites essential oil has potential to be used in the control of A. retroflexus L., which has high allelopathic effect on seed germination and seedling development of L. sativum L., T. aestivum L., A. retroflexus L.