Multigenerational exposure to cerium oxide nanoparticles: Physiological and biochemical analysis reveals transmissible changes in rapid cycling Brassica rapa

• Multigenerational exposure to CeO2NPs reduced plant biomass of offspring generations of Brassica rapa.
• Multigenerational exposure to CeO2NPs reduced seed yield and quality of Brassica rapa.
• Multigenerational exposure to CeO2NPs resulted in higher oxidative stress in subsequent generations of Brassica rapa.

The unique redox chemistry on the surface of cerium oxide nanoparticles (CeO2NPs) and their broad applications in society have caused many concerns over the release and accumulation of these materials in the environment. Many investigations have been conducted with regard to the environmental health and safety effect of CeO2NPs, including their impact on plant health. However, most previous studies were conducted on the early seedling development stage, with a small number of recent investigations examined the impact of CeO2NPs throughout the life cycle of plants (e.g. from seed to seed). However, the long term, multigenerational impact of CeO2NPs on plants remains unclear. The main aim of this study was to assess the physiological and biochemical consequences of multi-generational (three) CeO2NPs exposure over a range of concentrations (0–1000 mg/L) on B. rapa. The results showed that plants in the second and third generation displayed slower plant growth and smaller biomass. The Brassica plants also bore 39%, 59% and 61% less siliques after two generations of exposure to 10, 100 and 1000 mg/L of CeO2NPs. The numbers of seeds produced per silique were also reduced in the third generation plant by over 50% following the exposure to 100 and 1000 mg/L of CeO2NPs. In addition, plants in the later generations generally contained higher concentrations of hydrogen peroxide (H2O2) in their tissues. Altogether, our results suggest that the second and third generation plants might have experienced higher oxidative stress than the first generation plants. This study provided first evidence that the impact of CeO2NPs varied across generations and long term evaluation extending several generations of plant growth is necessary to obtain a realistic understanding on the long term impact of engineered nanoparticles.

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