Citation:

Rico, C., O. Abolade, D. Wagner, B. Lottes, J. Rodriguez, R. Biagioni, AND C. Andersen. Wheat exposure to cerium oxide nanoparticles over three generations reveals transmissible changes in nutrition, biochemical pools, and response to soil N. JOURNAL OF HAZARDOUS MATERIALS. Elsevier Science Ltd, New York, NY, 384:121364, (2020). https://doi.org/10.1016/j.jhazmat.2019.121364

Impact/Purpose:

Engineered nanoparticles (ENMs) have been recognized as valuable components of new technologies and are currently being used in a variety of consumer products due to their unique physical, chemical, and electrical properties. The properties that make these particles functionally unique also may influence their toxicity to organisms in ecosystems. CSS’s Emerging Technologies research is designed to identify potential adverse effects of these materials in the environment, including toxicity to plants and animals. Ideally EPA would like to understand mechanisms of response to ENMs in order to develop predictive tools to evaluate new nanomaterials as they are developed. To gain better understanding of the intergenerational effects of ENMs in plants, we examined the influence of CeO2-NPs on the growth, reproductive output, and seed quality of third generation wheat whose parents were previously exposed to CeO2-NPs for two generations. The results showed that prior exposure to CeO2-NPs, as well as exposure to CeO2-NPs during the 3rd generation, increased the root biomass in daughter plants. When wheat received CeO2-NPs in year 3, root Mg, P, K, Ca, Mn and Fe contents also were increased. Soil N level tended to influence the magnitude of response to the CeO2-NP treatments, but not the direction of response. The isotopic ratios of N were only affected by current and not parental exposure to CeO2-NPs, indicating that the effects on metabolism only occur during the year of exposure and are not transferred from one generation to the next. Fatty acid composition of seeds from 3rd generation plants was also influenced both by prior exposure and 3rd year exposure to CeO2-NPs. The results provide insight into the underlying physiological responses of wheat to CeO2-NPs exposure, including the interacting role of soil nutrition, which can influence plant response to ENMs. Overall, the results demonstrate the potential for long-term transgenerational shifts in wheat growth and grain quality in response to CeO2-NP exposure and should be considered in any risk assessment addressing the release of ENMs to the environment.

Description:

This study investigated the effects of third generation exposure to cerium oxide nanoparticles (CeO2-NPs) on biomass, elemental and 15N uptake, and fatty acid of wheat (Triticum aestivum). At low or high nitrogen treatment (48 or 112 mg N), seeds exposed for two generations to 0 or 500 mg CeO2-NPs per kg soil treatment were cultivated for third year in soil amended with 0 or 500 mg CeO2-NPs per kg soil. The results showed that parental and current exposures to CeO2-NPs increased the root biomass in daughter plants with greater magnitude of increase at low N than high N. When wheat received CeO2-NPs in year 3, root elemental contents increased primarily at low N, suggesting an important role of soil N availability in altering root nutrient acquisition. The δ15N ratios, previously shown to be altered by CeO2-NPs, were only affected by current and not parental exposure, indicating effects on N uptake and/or metabolism are not transferred from one generation to the next. Seed fatty acid composition was also influenced both by prior and current exposure to CeO2-NPs. The results suggest that risk assessments of NP exposure may need to include longer-term, transgenerational effects on growth and grain quality of agronomic crops.

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