Wednesday, November 4, 2009
Ballroom A+B (Camino Real Hotel)
Our main objective was to study the possible toxicity of engineered ZnO nanoparticles (NPs), and Zn+2 ions on seed germination and root elongation in alfalfa (Medicago sativa). Alfalfa seeds were germinated in 0, 50, 100, 200, 400, 800, and 1600 mg/L of ZnO NPs and in 0, 0.05, 0.5, 5.0, 10, 50 and 250 mg/L of Zn(NO3)2. The data showed a 40% reduction in seed germination at 800 and 1600 mg/L of ZnO NPs and at 50 and 250 mg/L of Zn(NO3)2. Inhibitory concentration of 50% (IC50) was observed at 800 and 1600 mg/L of ZnO NPs and at 250 mg/L of Zn(NO3)2 . Alfalfa root growth significantly decreased at 50 mg/L of Zn(NO3)2. Seedlings treated with 1600 mg/L of ZnO NPs had 4,700 mg Zn kg-1 dry weight (DW). While seedlings treated with 250 mg/L of Zn(NO3)2 had about 3500 mg Zn kg-1 DW.