PHYTOTOXICITY OF NANOPARTICLES TO SEED GERMINATION OF PLANTS

Phytotoxicity is an important consideration to understand the potential environmental impacts of manufactured nanoparticles, which ultimately accumulated in soil. In the present study, our aim was to assess the effects of two metal oxide nanoparticles (NPs), nano-ZnO, nano-Fe2O3 and one carbon based (fullerene) NPs, on seed germination, root and shoot elongation of wheat, rice, green gram and cucumber plants. These parameters were quantified following exposure to each type of NPs at different concentrations, from 10 mg/L to 1000 mg/L. Inhibition of root growth varied greatly among NPs and plant types. Among NPs, nano-ZnO found to be most phytotoxic, followed by nano-Fe2O3 and fullerene. Reduction in root and shoot growth found to be a more sensitive parameter than germination percentage. Results also indicated that NPs at low concentrations can be useful for seedling growth. Fifty percent inhibitory concentrate ions (IC50) varied with type of NPs and plant species. IC50 value of nano-ZnO was about 50 mg/L for cucumber and 100 mg/L for other tested plant species. Overall, this study has shown that direct exposure of germinating seeds to nanoparticles may cause phytotoxicity and underscores the need for eco-responsible disposal of wastes and sludge containing NPs which ultimately comes into soil system.