Abstract
We studied the allelopathic interference between the Zizyphus spina-christi and Prosopis juliflora. Dried leaves from both species were milled to prepare leaf extracts of 0, 5, 20, 40, 60 and 100 g/l concentrations. The leaf extracts of P. juliflora and Z. spina-christi were used to irrigate seedlings of each other. Zizyphus spina-christi leaf extract decreased the root parameters (total root length, root surface area, number of tips and root Volume) of P. juliflora and the decrease was concentration dependent. However, leaf extract of P. juliflora Stimulated the parameters of Z. spina-christi roots, The root length, root surface area and number of tips increased with increasing concentration, except at 100 g/l concentration. The study revealed that Z spina-christi leaf extract was inhibitory to the growth of another plant species, it was reported first time.