Impact of zinc oxide and copper oxide nano-particles on physiological and molecular processes in Brassica napus L.

Abstract

In the present study, the effect of ZnO and CuO nano-particles was investigated on some growth and physiological parameters of Brassica napus L. cultivar SLM046. The seedlings were grown in 1/2 strength Murashige and Skoog medium supplemented with either ZnO or CuO NPs @ 0, 10, 100 and 1000 mg l−1 for 10 days. The results indicated that each nano-particle induced the growth responses at 10 mg l−1 concentration. The decreases were observed in root and shoot elongation and root dry weights under higher concentrations (100 and 1000 mg l−1) treatments. Imposing canola seedlings to each nano-particles lead to increase and decrease in sugar and protein contents, respectively. The expression of four genes involved in signal transduction pathway including Auxin Responsive Protein, Protein Kinase, MPK3 and MPK4 was also investigated using semi quantitative RT-PCR. Exposure of canola germinated seeds to each nano-particle caused changes in transcript levels of all four genes in root and shoot tissues. Our data indicate that at 10 mg l−1 concentration, ZnO and CuO nano-particles supplementation promoted the growth response in B. napus, while higher concentrations resulted in toxic responses.