Pollution with heavy metals is one of the most noticeable environmental problems due to their adverse ecological effects reported by many publications [1-3]. Toxic metals contaminating the soils create difficult conditions for most plants growing in them. They may cause various morphological, physiological, and biochemical dysfunctions in plants, either directly or indirectly, and cause damaging effects [2]. Heavy metal toxicity in plants varies with plant species, specific metal, content of metal, its chemical form, soil composition and pH. Some metals, including Cu, Mg, Co, Zn and Cr, are essential to plants in trace amounts, but only when metals are present in bioavailable forms, and at excessive levels they have the potential to become toxic to plants [4]. Others, such as Mg,