Influence of six essential oils on invasive Solidago canadensis L. seed germination.

Solidago canadensis L. (SC) (Canadian goldenrod) is a dangerous plant invader in Europe, which suppress the indigenous flora. Essential oils (EOs) are considered biological control agents. GC-MS analysis for identification of main components was conducted and the potential phytotoxicity of six EOs were also evaluated. Limonene and ß-thujone were dominant components in Salvia officinalis L., menthone and menthol in Mentha × piperita L., carvacrol in Origanum vulgare L., estragole/anisole and anethole in Foeniculum vulgare Mill., limonene and carvone in Anethum graveolens L., and anethole in Pimpinella anisum L. Along with EOs, anethole, anisole, camphor, carvone, estragole, limonene, menthol, menthone, thujone and thymol were used independently to evaluate phytotoxic effect against Canadian goldenrod seed germination. A significant inhibitory effect was registered for origanum (1.250 µg.ml-1). The influence of single components was significant. The highest phytotoxic activity was registered with anethole and estragole. Phenolic compounds were the inhibitoriest, followed by oxygenated and hydrocarbon monoterpenes.

Phytotoxic and Antibacterial Activity of Essential Oil of New Peppermint Cultivar.

A new menthol cultivar of Mentha x piperita L. bred in East Slovakia was evaluated for the biological activity of its essential oils (EOs). The content and composition of the EO components changed during plant development and the different effects of samples collected each month (April - September) within the growing season were noted. EOs are considered to be an important source of potential allelochemicals. Changes in EO composition influenced phytotoxic activity. Stimulation and inhibition of seed germination and root elongation occurred with different EO concentrations. The four tested bacterial strains: presented different resistance to the samples collected in different growing periods.