engleski

Phytoremediation - green solution for pollution

Industrial, domestic, agricultural, medical and technological applications of heavy metals have led to their wide distribution in the environment, raising concerns over their potential effects on human health and environment. Among all heavy metals, the most common of them are cadmium and lead, which can occure as byproducts of petrochemical industries and traffic. Phytoremediation, as a new biotech method, is considered as an ecological, inexpensive and aesthetically acceptable, in situ technology to remediate heavy metals from contaminated soils. The potential use of fast-growing trees with high biomass production in the phytoremediation of soil has been recognized recently. The response to the presence of heavy metals in the plant leads to increased oxidative stress in the form of creation of reactive oxygen species or ROS. The first line of defence against harmful ROS consists of antioxidant enzymes. Plants ability to accumulate heavy metals present in the soil and its resistant to their effects lead to the possible potential of poplar (Populus nigra var. italica) in the phytoremediation of cadmium and lead. Therefore, as there is a small number of scientific papers which examine the synergistic effect of two or more heavy metals, an outdoor pot experiment was designed in order to evaluate changes of poplar growth parameters during prolonged exposure with 4 harvest points (GP1-GP4), allowing the consideration of prolonged adaptions to heavy metal stress. During 77 days long growing period (from July to September) in soil, poplar (Populus nigra var. italica) was treated with combination of different concentrations of Cd (w = 10, 25, 50 mg kg-1 soil) and Pb (400, 800, 1200 mg kg-1 soil). The aims were to explore the accumulation and distribution of Cd and Pb in different plant parts (leaf, stem, root), the malondialdehyde content (an indicator of membrane lipid peroxidation) in order to estimate the extent of oxidative stress as well as the potential role of antioxidant enzyme activity (superoxide dismutase, guaiacol peroxidase, catalase and ascorbate peroxidase) in response to oxidative stress caused by the accumulation of different amounts of heavy metals. A statistical analysis based on the Random Forests Analysis (RFA), a new and powerful statistical classifier, was performed. The importance of antioxidant enzyme activity, different amounts of Cd and Pb, soil and meteorological parameters change in different plant parts. However, the preliminaryresults highlighted a key role of the catalase activity in response to the oxidative stress in all plant parts.

antioxidant enzymes; cadmium; lead; oxidative stress; phytoremediation; poplar

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