Determination of Allelopathic and Antimicrobial Effects of Four Different Plant Species

Abstract

The investigation of allelopathic and antimicrobial effects of four different plant extracts is the aim of this study. The aqueous extract of plants (Lepidium draba L., Acroptilon repens (L.) DC., Thymus kotchyanus Boiss&Hohen. var. kotchyanus, Inula peacockiana (Aitch.&Hemsl.) Koravin,) were applied to seedlings of cultivated (Pisum sativum L. and Hordeum vulgare L.) and weed (Amaranthus retroflexus L. and Portulaca oleraceae L.). Seedlings were irrigated with aqueous extract (1 %) for 15 days to observe the physiological responses. The morphological changes, chlorophyll levels and phytohormone concentrations were determined. The Lepidium draba and Inula peacockiana extracts affected development of all of the target seedlings and caused lesion on the leaves. Acroptilon repens and Thymus kotschyanus extracts caused a decrease in gibberellic acid (GA) whereas increase in absisic acid (ABA) levels. For investigation of antimicrobial activities, hexane, methanol and water extracts were prepared. Extracts were applied on Bacillus cereus, Staphylococ aureus, Pseudomonas syringae and Escherichia coli for antibacterial and Rhizoctonia solani, Fusarium oxysporum and Aspergillus niger for antifungal effects. Inula peacockiana and Acroptilon repens extracts had a great antimicrobial activity. While all plant extracts inhibited Rhizoctonia solani, Fusarium oxysporum growth and spore development of Aspergillus niger. The antifungal activity of extracts were better than antibacterial activity. As a conclusion, these plants have allelopathic potential for natural weed control and antimicrobial potential for medicinal uses.