Differential Effects of Cerium Oxide Nanoparticles on Rice,Wheat,and Barley Roots: A Fourier Transform Infrared (FT-IR) Microspectroscopy Study

Abstract

Cerium oxide nanoparticles (nCeO₂) have extensive industrial applications, and concerns regarding their threat to the environment have been raised. This study includes structural analysis of intact root xylem of rice (Oryza sativa L.), wheat (Triticum aestivum L.), and barley (Hordeum vulgare L.) seedlings exposed to nCeO₂ suspensions (0, 62.5, 125, 250, and 500 mg L⁻¹). Fourier transform infrared microspectroscopy was applied to determine compositional alterations in the root xylem, and principal component analysis (PCA) was carried out to examine spectral differences between nCeO₂ treatments. Results demonstrated that nCeO₂ at > 125 mg L⁻¹ changed the region of spectra around 1696-1760 cm⁻¹ in rice root, 125 and 250 mg L⁻¹ modified 1744-1792 cm⁻¹ in wheat, and 62.5 and 125 mg L⁻¹ altered 1727-1760 cm⁻¹ in barley. PCA afforded the clustering of nCe02 treatments at 0 and 62.5 mg L⁻¹ in rice and wheat and 0 and 500 mg L⁻¹ in barley. Furthermore, major peaks at 1744 or 1760 cm⁻¹ appeared in primary PC and 1728 cm⁻¹ in secondary PC score loadings. These findings illustrated that nCeO₂ induced compositional modifications in the root xylem of cereals.