Differential expression of Lead accumulation during two growing seasons by desert shrub Acacia victoriae L.

Abstract

In desert reclamation strainer plants can be used for improvement and decrease pollution of soil and water. This technology can be used to remove both inorganic and organic contaminants in soil. In this study, one year old <em>Acacia victoriae </em>seedlings were exposed to Pb (NO₃)₂ in 5 different concentrations; 0, 50, 250, 500 and 1000 mg Pb L^-1 for 45 days in two growing seasons. Subsequently, the heavy metal concentrations were measured in different plant tissues by Atomic Absorption Spectroscopy (AAS) for two growing periods. In addition, some physiological and morphological parameters (root and plant length, root diameter, leave area, dry weight, chlorophyll a, band total) were measured. Based on the results, the visible toxicity symptoms (chlorosis and necrosis) appeared only to the highest concentration (1000 mg Pb L⁻¹) in both growing seasons. The results also showed that application highest concentration of Pbreduced the physiological and morphological parameters as compared to the control seedlings. The accumulation of Pbwas influenced by the Pbconcentration in the growth medium and the growing seasons as well. With respect to the more accumulation of Pbin the roots tissues than aboveground tissues, indicating <em>A.victoriae</em> as a good option for phytostabilization of Pbcontaminated soils. Furthermore if <em>A.victoriae </em>is planted for Pb phytoextraction, therefore the harvest of aboveground should be done at the fall season. Meanwhile concentrations of Pb in the aboveground parts were more than roots at the fall season. In conclusion <em>A.victoriae</em> a native to the arid zone appeared to be hyper tolerate, accumulate high concentrations of Pb and it could be regarded as a potential accumulator. In addition<em> A.victoriae</em> have high application value in repairing Pb contaminated soils and is suitable and effective choice to be used as a tool of phytoremediation in industrial sites of the arid zones. Our findings suggest that <em>A.victoriae</em> has the advantages of high capacity for adaptation to poor, easy cultivation, deep root system, high tolerance to the drought, saline soils and Pb and could use as candidate plant for environmetals monitoring.