Abstract
The objective of this study was to determine the allelopathic effect of mesquite (Prosopis juliflora) aqueous root extract on germination of acacia varieties in Saudi Arabia. The root samples were collected and cleaned manually. P. jiliflora roots were crushed separately in a blender. An aqueous extract was made for roots and tested at concentration (50% and 100%) on acacia varieties germination in Petri dishes and soil. Phytochemicals of aqueous extract of roots were examined by TLC. The results showed that Acacia gerrardii had the highest number of germination and rates followed by Acacia tortlis and Acacia raddiana. All results were significantly different at level p-value =0.005. Germination inhibition % of Acacia gerrardii treated by Prosopis juliflora DC. aqueous roots extract was high 50% at concentration of100% in both. When the lowest was 37.5 at concentration 50% in Petri dishes, Acacia raddiana showed high inhibition % in Petri dishes, 75% thus low was in soil 47% and Acacia tortlis was high soil 47% and 68% at concentration 50% and 100%.
It was low in Petri dishes 52% and 61.7% at concentration 50% and 100% respectively. Phytochemical screening of aqueous extracts of P. jiliflora roots showed the presence of alkaloids, cardiac glycosides, flavonoids, phlobatannins, saponins and tannins and the absence of Steroidal ring. The results of elution with TLC confirm the presence of secondary metabolites in roots aqueous extract of Prosopis juliflora. The study proposed a long-term field investigation into the allelopathic effect using various treatments including more species.