How does aquatic macrophyte Salvinia auriculata respond to nanoceria upon an increased CO 2 source? A Fourier transform-infrared photoacoustic spectroscopy and chlorophyll a fluorescence study

• Published in: Ecotoxicology and environmental safety 2019-05, Vol.180, p.526
• Main Authors: Pontes, Montcharles S, Grillo, Renato, Graciano, Daniela E, Falco, William F, Lima, Sandro M, Caires, Anderson R L, Andrade, Luís H C, Santiago, Etenaldo F
• Format: Article
• Language: English
• ISSN: 1090-2414

With the continued increase of technological uses of cerium oxide nanoparticles (CeO NPs or nanoceria) and their unregulated disposal, the accumulation of nanoceria in the environment is inevitable. Concomitantly, atmospheric carbon dioxide (CO ) levels continue to rise, increasing the concentrations of bicarbonate ions in aquatic ecosystems. This study investigates the influence of CeO NPs (from 0 to 100 μgL ) in the presence and absence of an elevated bicarbonate (HCO ) ion concentration (1 mM), on vibrational biochemical parameters and photosystem II (PSII) activity in leaf discs of Salvinia auriculata. Fourier transform-infrared photoacoustic spectroscopy (FTIR-PAS) was capable of diagnostic use to understand biochemical and metabolic changes in leaves submitted to the CeO NPs and also detected interactive responses between CeO NPs and HCO exposure at the tissue level. The results showed that the higher CeO NPs levels in the presence of HCO increased the non-photochemical quenching (NPQ) and coefficient of photochemical quenching in dark (qP ) compared to the absence of HCO . Moreover, the presence of HCO significantly decreased the NPQ at all levels of CeO NPs demonstrating that HCO exposure may change the non-radiative process involved in the operation of the photosynthetic apparatus. Overall, the results of this study are useful for providing baseline information on the interactive effects of CeO NPs and elevated HCO ion concentration on photosynthetic systems.