Allelopathic Potential of Volatile Oils from Mentha piperita and Chrysanthemum coronarium Growing in Western Algeria

Background: The allelopathic effects of the essential oils of M. piperita and C. coronarium on seed germination of two wheat species qualify them as bio-herbicides. Objective: In order to search for natural plant-based products that may have herbicidal action, we selected two plant species, M. piperita and C. coronarium, to evaluate the allelopathic potential of their essential oils on wheat seed germination of two wheat species. Methods: Aerials parts of M. piperita and C. Coronarium were subjected to hydrodistillation using a Clevenger-type apparatus to extract essential oils, followed by characterization using gas chromatography coupled with mass spectrometry. Bioassays were conducted with ethanol as the organic solvent, employing three concentrations (0.25, 0.5, and 0.75 μl/ml of oil/ethanol) to assess their effects on the seed and seedling growth of two wheat species. Results: Under laboratory conditions, extracts of Mentha piperita and Chrysanthemum coronarium oils at varying concentrations (0.25 μl, 0.5 μl, and 0.75 μl) were examined for their effects on two wheat species (Triticum durum L. and Triticum aestivum L.). The yields of the obtained oils were 1.19% and 0.25%, respectively. The chemical composition of the essential oils extracted from M. piperita and C. coronarium was dominated by oxygenated monoterpenes, representing 97.5% and 94.9%, respectively. The tested essential oils strongly inhibit seed germination and seedling growth (root length LR and shoot length LPA) of both wheat species studied. The inhibition increased as the oil concentration increased, although this increase differed between the two species. This study has shown that the tested essential oils possess an interesting inhibitory allelopathic potential. Conclusion: The findings of this study indicate that the tested essential oils possess promising allelopathic properties, suggesting them as natural bio-herbicides.