Cerium Oxide Nanoparticles Modify the Antioxidative Stress Enzyme Activities and Macromolecule Composition in Rice Seedlings
2013
Rico, Cyren M. | Morales, Maria I. | McCreary, Ricardo | Castillo-Michel, Hiram | Barrios, Ana C. | Hong, Jie | Tafoya, Alejandro | Lee, Wen-Yee | Varela-Ramirez, Armando | Peralta-Videa, Jose R. | Gardea-Torresdey, Jorge L.
Cerium oxide nanoparticles (nCeO₂) have been shown to have significant interactions in plants; however, there are limited reports on their impacts in rice (Oryza sativa). Given the widespread environmental dispersal of nCeO₂, it is paramount to understand its biochemical and molecular impacts on a globally important agricultural crop, such as rice. This study was carried out to determine the impact of nCeO₂ on the oxidative stress, membrane damage, antioxidant enzymes’ activities, and macromolecular changes in the roots of rice seedlings. Rice seeds (medium amylose) were grown for 10 days in nCeO₂ suspensions (0–500 mg L–¹). Results showed that Ce in root seedlings increased as the external nCeO₂ increased without visible signs of toxicity. Relative to the control, the 62.5 mg nCeO₂ L–¹ reduced the H₂O₂ generation in the roots by 75%. At 125 mg nCeO₂ L–¹, the roots showed enhanced lipid peroxidation and electrolyte leakage, while at 500 mg L–¹, the nCeO₂ increased the H₂O₂ generation in roots and reduced the fatty acid content. The lignin content decreased by 20% at 500 mg nCeO₂ L–¹, despite the parallel increase in H₂O₂ content and peroxidase activities. Synchrotron μ-XRF confirmed the presence of Ce in the vascular tissues of the roots.
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