Exposure of Wheat Plants to Cerium Oxide Nanoparticles for Two Generations Affects the Third Generation's Responses...

The effects of parental stress on the performance of the next generation plants exposed to another contaminant were investigated. Wheat plants were exposed to cerium oxide nanoparticles (CeO₂-NPs) in the first and second generations and to perfluorooctanesulfonic acid (PFOS) in the third generation. Phenotypic or metabolic responses were assessed at 21 day (short-term exposure) or 90 day (long-term exposure) exposure periods. Biomass production, chlorophyll content, enzyme activity, and membrane damage were measured during short-term exposure, while elemental and PFOS concentrations and grain metabolites were analyzed during long-term exposure. Results showed that continued exposures to CeO₂-NPs and PFOS improved chlorophyll content but reduced concentrations of important macro- and microelements in the grains of daughter plants. PFOS was accumulated in wheat grains, while metabolomic analysis revealed that the grain metabolite composition was significantly altered. Continued exposure to CeO₂-NPs followed by exposure to PFOS decreased the abundances of most metabolites (22 out of 34). Consistent and repeated previous exposures to CeO₂-NPs also progressively reduced the concentrations of sucrose-6-phosphate, adenine, glutamic acid, and other organic acid metabolites. The findings suggest that the prior generation's exposure could still influence succeeding progeny generations via invisible changes in metabolite and elemental composition of grains.