The aim of the present work was to evaluate the allelopathic effect of different concentrations (25, 50 and 100 µg/ml) of root exudates and aqueous leaf extracts of three desert plants (Artemisia judaica, Asphodelus microcarpus and Solanum nigrum) on two weed plants (Portulaca oleracea and Phalaris minor). In laboratory experiment, the three studied plants possessed herbicidal effects that significantly inhibited germination, seedling growth and chlorophyll content of P. oleracea and P. minor; the inhibitory effect was proportional to the concentrations applied. Artemisia judaica and A. microcarpus were the most effective root exudates against P. oleracea while A. microcarpus was the most effective against P. minor compared to the other examined root exudates. Meanwhile, A. judaica was proved to be the most effective leaf extract against P. oleracea and P. minor followed by A. microcarpus and then S. nigrum. A number of phenols and flavonoids with known allelopathic potential was identified in the leaf extracts of the three studied plants and could explain their inhibitory effect on P. minor and P. oleracea plants. Generally, the aqueous leaf extracts showed greater allelopathic effects than the root exudates. However, both root exudates and aqueous leaf extracts of the three tested plants are attractive to be utilized in bio- herbicidal development program towards active weed management.
Key words: Allelochemicals, allelopathy, desert plants, eco-friendly, flavonoids, phenols, secondary metabolites.
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