PHYTOREMEDIATION POTENTIAL OF BRASSICA NAPUS IN HEAVY METAL POLLUTED ENVIRONMENT ALINA STINGU, IRINA VOLF, BRANDUSA ROBU and VALENTIN I. POPA, “Gheorghe Asachi” Technical University of Iasi, Faculty of Chemical Engineering and Environmental Protection, 71 Mangeron Blvd, 700050, Iasi, Romania astingu@ch.tuiasi.ro , iwolf@ch.tuiasi.ro MATERIAL AND METHOD Germination tests were carried out in Petri (10 rape seeds / each) dishes which were incubated in a thermostatic chamber at 25-27 C for 10 days. Three different concentrations (10, 25, 50mg/L) of heavy metals were tested using CuSO4·5H2O and CdCl2·2H2O salt. Seeds were surface sterilized using NaOCl 1% for 20min and germinated in Petri dishes moistened with distilled water. After one weeks seedlings with uniform size were selected and transferred to plastic pots containing 160mL Hoagland nutrient solution and different concentration of copper and cadmium ions (10, 25, 50mg/L). Nutrient solution was change every week. After 3 weeks the plantlet were harvested and analyzed. Plantlet dry samples were mineralized in nitric acid (65%) and H 2 O 2 (30%) on a hot plate at 120 C,for at least five hours [3] and copper/ cadmium ions concentrations were spectrophotometrical determined by using a GBC Avanta atomic absorption spectrophotometer. The chlorophyll was extracted in 80% acetone and spectrophotometrical determinate by reading the absorbance at fixed wavelength 470, 646, 663nm. RESULTS AND DISCUSSION Tested solution Chl a Chl b Chl a+b Control 224.17 34.72 258.99 Cu-10 291.06 121.27 412.33 Cu-25 332.63 85.62 418.26 Cu-50 89.20 53.51 142.72 Cd-10 246.06 83.04 329.11 Cd-25 344.08 93.68 437.76 Cd-50 343.61 76.79 420.41 Phytoremediation is an in situ low-cost and low impact technology that has received increasing attention over the last fifteen years, owing to its environmentally friendly nature and easy large-scale applicability [1]. Metal hyperaccumulator plants can grow in soils containing high concentration of metals and can accumulate heavy metals at high concentrations in shoots. Earlier reports suggests that Brassica napus can be a useful candidate for phytoextraction of heavy metals due to its high above ground biomass, faster growth and high Cd (II) uptake [2]. The aim of this study is to evaluate the bioaccumulation potential and Recovery % of rape plant under copper and cadmium stress. Assimilatory pigments concentrations (μg/g) for rape plantlet Germination test results show that rape plantlet elongation was inhibited under heavy metal stress, strongly under copper ions (Fig. 1). This could be correlated with a specific higher concentrations and bioaccumulation of copper ions in rape plant tissues comparing with the case of cadmium stress conditions (Fig.3, 4). The green biomass accumulation in Brassica napus was inhibited in the presence of copper and cadmium ions and show a decreasing trend with increasing metal contamination level (Fig. 2). Bioaccumulation show a decreasing trend for rape plant, with increasing heavy metal concentration in the growth medium. In germination test bioaccumulation seems to registered higher values under copper stress than for cadmium. Recovery % values for both germination tests experiments and hydroponics culture suggested that rape plant is suitable for phytoremediaton (Fiig. 5, 8) Hydroponic culture experiment evidenced the affinity of rape plant to accumulate cadmium. The highest cadmium concentration s were registered under 25mg/L metal concentration treatment (Fig.6). For copper hydroponic culture contamination, the concentration of heavy metal in rape plant tissues increased with increasing metal concentrations in the medium. Bioaccumulation and Recovery % shown higher values under cadmium stress. Those parameters decreased with increasing the ions concentration in the growth medium(Fig.7, 8). Rape plant present special affinity for copper bioaccumulation into the roots area. Cadmium ions were bioaccumulated into the aerial parts. Rape plant (Brassica napus) is suitable for phytoremediation process, both for Cu(II) and Cd(II) contaminated environment as long as Bioaccumulation and Recovery % registered higher values. Fig.1 Rape plantlet elongation under Cu(II) and Cd(II) stress Fig.2 Rape plantlet green biomass under Cu(II) and Cd (II) stress Fig.3. Cu(II) and Cd (II) concentration in rape plant tissue obtained in germination tests Fig.4 Cu(II) and Cd(II) bioaccumulation registered in germination test Fig.5 Cu(II) and Cd(II) Recovery % registered in germination test Fig.6 Cu (II) and Cd (II) concentration registered in hydroponic culture Fig.7 Cu (II) and Cd (II) bioaccumulation registered in hydroponic culture Fig.6 Cu (II) and Cd (II) Recovery % registered in hydroponic culture Fig.9 Copper and cadmium translocation factor (TF) in rape plant Copper ions are preferentially accumulated into the roots level mean while the cadmium ions are translocated to the upper parts of Brassica napus plant (Fig.9) Bioaccumulation = (μg metal / g dry weight plant) / (μg metal /g nutrient solution) [4] Recovery % = (metal content in plant tissues/ metal content in medium) x 100 [5] This paper is supported by BRAIN “Doctoral Scholarships as an investment in intelligence” projects, financed by The European Social Found and Romanian Government REFERENCES [1]. 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Xu, L Wang., Joint effects of arsenic and cadmium on plant growth and metal bioaccumulation: A potential Cd-hyperaccumulator and As-excluder Bidens pilosa L., J. Hazard. Mater. 161(2009) 808-814. (TF) = The ratio of metal concentration in shoots/ The ratio of metal concentration in roots [6] INTRODUCTION CONCLUSIONS