Investigation of the phytoremidation of lead in the metallicolous and non- metallicolous species Matthiola.

Lead is one of the most abundant and toxic heavy metals which can have lethal effects on plants. The Pb contamination is produced by mining, industrial, activities and fossil fuel burning. Some metallophytes plants belong to Brassicaceae family are able to grow in soils contaminated with heavy metals. The purpose of this study is to evaluate the resistance and lead accumulation of the metallicolous species Matthiola flavida collected from the vicinity of the Irankouh Pb/Zn mine in Isfahan, Iran, which is compared with its non- metallicolous species Matthiola incana to used Pb phytoremediation. Non-metallicolous (Matthiola incana) and metallicolous plants (Matthiola flavida) were transferred to hydroponic mediums and after proper vegetative growth, they were exposed to 0, 10, 50, 100, 150 mg/L treatments of lead for 14 days. The results showed by increasing lead concentration, the growth of both species significantly decreased, but this reduction in growth was always greater in the non-metallicolous species, so that at the highest stress level, the dry weight of shoots and roots decreased in the metallicolous to %7.1 and % 28.8, but in the non-metallicolous to %69.9 and %60.8 in comparison with their control, respectively. With increasing the concentration of Pb in the medium, the accumulation of lead in the roots of both species are enhanced, but Pb concentration in the roots and translocation factor of the metallicolous species compared to the non-metallicolous species was more than 4-folds at the lowest stress level, which decreased with increasing lead concentration. Then, the compatible mechanisms of the metallicolous species have the ability to control the transfer of lead to the shoot in different concentrations, which makes it suitable for growing in lead-contaminated areas.