Allelopathic activity of micropropagated Origanum vulgare ssp. hirtum and its effect on mitotic activity

We determined the essential oils composition, allelopathic activity and effects on mitotic activity of four micropropagated plants of Origanum vulgare L. ssp. hirtum (Link) Ietswaart. These plants were obtained from two types of explants, the stem tips and the germs of its seeds, originating from the same plant. Gas-chromatography analysis of essential oils revealed the differences between the plants, with carvacrol (48.3 – 61.5%) being the major compound. We evaluated the allelopathic activity of micropropagated oregano and its effect on mitotic activity using water infusions made from the aerial parts of the 2-years old plants under laboratory conditions, on root elongation of Cucumis sativus L. and Allium cepa L. chromosome aberration tests. The test plants exhibited different degrees of allelopathic effects. Two of the plants exerted higher inhibitory effects on the root elongation and acted as stronger spindle inhibitors in mitotic cells.