This experiment was conducted in the Nursery of the Department of Floriculture, Ornamental Horticulture and landscape Gardening - Faculty of Agriculture Shatby - University of Alexandria from August 1st to February 1st in two successive seasons (2014-2015 and 2015-2016), to study the biological treatment of contaminated soil with the use of some ornamental trees, A tree with a type of inoculation obtained from the nursery of the Department of Forestry and Wood Technology - Abyss - Alexandria University:Acacia saligna: Rhizobiumsp < em>., (which used for inoculation of A. saligna root).The treatments of the three elements (cadmium - zinc - lead) were: Control - 250 mg/kg - 500 mg/kg and 1000 mg/kg soil. The first part is inoculated seedlings and the second part uninoculated seedlings. The most important results obtained can be summarized as follows:
The application of the high level of heavy metals (500 and 1000 mg/kg) led to decrease the growth parameters (growth rate, total dry weight and nodule/root ratio). The negative effect of the pollutants was more significant in uninoculated seedlings with Rhizobium, i.e., the inoculated ones had displayed growth parameters significantly higher than those of uninoculated ones.
§ Both of Cd and Pb had harmful impact on plant growth than what Zn did.
§ Total chlorophyll of the phyllodes was decreased as a result of application of heavy metals. Both of Pb and Zn had detrimental impact on chlorophyll content relative to Cd.
§ Analyzing the Rhizosphere of the seedlings treated with the heavy metals, it has been found that lead was the most metals fixed in the soil as it compared with Zn and Cd, particularly under high levels of such metals amended.
It is recommended, however, to use A. saligna seedlings as a phytoremediator for heavy metals polluted soil, since it is regarded to be tolerant to such stress, in addition to potential of the Rhizobium bacterial, the symbiotic partner of the plant, for increasing the efficiency of the phytoremediation.