Lead uptake and phytoremediation in Marrubium cuneatum plant under different concentrations of sulfur (S)

Phytoextraction is one of the phytoremediation strategies in which plants take up pollutants from the environment and accumulate them in the plant shoot. Marrubium cuneatum (Lamiaceae) can be used in phytoextraction due to the relatively high biomass production and lead (Pb) accumulation in its shoots. In this research, the effect of increased sulfur (S) concentration on Pb absorption potential of Marrubium cuneatum has been investigated. Plants were cultured in hydroponic media under three S concentrations: 12, 24 and 48 mg/l. Pb (as Pb (NO3)2) was added to the medium in 200 mg/l concentration. After two weeks, the plants were harvested and the roots and shoots were separated. Root and shoot length, fresh and dry weight along with Pb content in root and shoot dry matters were measured. The results indicated that only shootlength, root fresh weight and shoot Pb content, under different concentrations of S, showed a significant difference and other parameters did not show any significant differences. The highest changes were observed in shoot Pb content, with an average Pb concentration of 49 mg/kg, in 12 mg/l S treatment, reaching 1050 mg/kg, in 24 mg/l S treatment. According to the results, it seems that increasing the amount of plant-available S to 24 mg/l can increase the shoot Pb concentration up to 1000 mg/kg but more S increase does not affect Pb absorption significantly.

Keywords:

Phytoremediation , Phytoextraction , Marrubium cuneatum , Sulfur , Lead