Reza Hesami - Department of Plant Biology, Faculty of Biological Sciences, Kharazmi University, Tehran, Iran.
Seyed Majid Ghaderian - Department of Biology, Faculty of Sciences, University of Isfahan, Isfahan ۸۱۷۴۶-۷۳۴۴۱, Iran.
Azam Salimi - Department of Plant Biology, Faculty of Biological Sciences, Kharazmi University, Tehran, Iran.

Phytoremediation is the use of plants to remove or detoxify contaminants. Phytoextraction, the plant s capability to absorb contaminants from soil, is the most favorable phytoremediation technology. This study aimed to investigate the effects of nitrogen (N) supply on lead (Pb) phytoremediation potential of Marrubium cuneatum (Lamiaceae), as a choice for phytoextraction. For this purpose, the plants were cultured in hydroponic medium containing N (as NH4NO3) at three different concentrations (30, 60 and 120 mg/l) under a 200 mg/l Pb treatment. After two weeks, the plant specimens were harvested and their root and shoot were separately measured for length, fresh and dry weight and Pb content. The results showed that root and shoot length, the fresh and dry weight of roots and shoots, and the root Pb content, under different concentrations of N in the culture medium did not show any significant changes, but the Pb accumulation in shoots increased significantly. Pb concentration in shoot dry matter, changed from 360 mg/kg, in plants supplied with 30 mg/l nitrogen, to 660 mg/kg in 60 mg/l nitrogen-supplied plants and eventually reached 1300 mg/kg in 120 mg/l nitrogen-supplied plants. Based on the results, it seems that increasing the amount of available nitrogen to M. cuneatum, leads to increased Pb absorption of it, so that it can accumulate Pb in the range found in hyperaccumulator plants (1000 mg/kg for Pb).

Phytoremediation, Phytoextraction, Marrubium cuneatum, Nitrogen, Lead (Pb)