LAUSR

Phytoremediation is an effective and low-cost technique for the rehabilitation and cleanup of lands polluted with heavy metals. Selection of native plant species could avoid the ecological risks that are associated with the usage of non-native species. However, utilizing native species in phytoremediation and restoration of lands polluted by heavy metals requires information about their seed germinability and propagation requirements. The aim of this work was to assess the effects of four heavy metals (cadmium, chromium, lead and zinc) on the germination and early seedling growth of Peganum harmala L., a native Mediterranean species that has the potential to restore arid degraded lands. The results display that the germination characteristics (percent seed germination and Timson’s index) and growth parameters (hypocotyl and radicle lengths) worsened as the concentrations of all the heavy metals increased. Cadmium was found to be the most toxic element regarding these parameters, with toxicity decreasing in the following pattern: Cd > Pb > Cr > Zn. Radicle growth was more affected by the heavy metals compared to hypocotyl growth and the seedlings appeared to be more resistant to Zn. The germination ability of P. harmala over a wide range of heavy metals suggests that this species can grow easily in polluted soils.