Effects of Acacia cyanophylla Lindl. extracts on seed germination and seedling growth of four crop and weed plants

The aqueous and organic extracts of the roots, stems, phyllodes, flowers, legumes, and seeds of Acacia cyanophylla Lindl. were assayed at different concentrations to assess their allelopathic potential. The extracts were tested on the seeds of 2 crops (Triticum aestivum L. and Lactuca sativa L.) and 2 weeds (Peganum harmala L. and Silybum marianum L.) species. The final germination percentages and the seedling shoot and root lengths were significantly reduced by the A. cyanophylla extracts as compared to the control. Aqueous extract from seeds was the strongest inhibitor of germination, shoot length, and root length for L. sativa and P. harmala. Triticum aestivum was tolerant to the aqueous extracts tested; however, S. marianum was moderately inhibited by those extracts. Organic extracts have reduced the germination of weed and crop seeds and seedling growth in high percentages. This study indicates that the biomass of A. cyanophylla contains allelochemicals and could be used as a postemergence herbicide.