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Intergenerational studies on the effects of cerium oxide nanoparticles in wheat
Citation:
Rico, C. AND C. Andersen. Intergenerational studies on the effects of cerium oxide nanoparticles in wheat. 11th International Conference on the Environmental Effects of Nanoparticles and Nanomaterials, Golden, CO, August 14 - 18, 2016.
Impact/Purpose:
The field of nanoecotoxicology is driven by concerns that engineered nanomaterials (ENMs) may have unknown deleterious effects to plants and other biota across ecosystems. In the last 10 years, thousands of studies have been reported on the impacts of ENMs in plants; however, there has been only one published article on the intergenerational effects of ENMs in plants. Intergenerational studies provide insights on whether succeeding generations of plants can develop sensitivity or tolerance to continuous exposure to ENMs. A soil microcosm study was performed where two generations of wheat were exposed to cerium oxide nanoparticles (nanoceria). The results revealed that seeds from parental plants treated with nanoceria had accelerated growth and earlier grain formation although total grain yield at harvest was not affected. Second generation plants also showed changes in the assimilation of carbon and nitrogen as well as the uptake of iron, manganese, calcium, and phosphorous. In addition, plants grown from previously exposed seeds had remarkably lower cerium accumulation in the roots indicating that second generation plants demonstrated enhanced sensitivity to cerium. The results demonstrate the impacts of long-term and continuous exposure of plants to nanomaterials and identify productive research approaches for assessing effects of ENMs on plants. This abstract contributes to CSS 2.6.2
Description:
The intergenerational impacts of engineered nanomaterials in plants are not yet well understood. A soil microcosm study was performed to assess the physiology, phenology, yield and nutrient uptake in wheat (Triticum aestivum) exposed to nanoceria (nCeO2). Seeds from parental plants that were exposed to 0, 125, and 500 ppm nCeO2 in soil at first generation (S1) were cultivated at factorial combinations of either 125 or 500 ppm nCeO2 treatment to produce second generation treated plants (S2). The factorial combinations for first/second generation treatments with 125 ppm nCeO2 were S1-Ce-0/Ce-0, S1-Ce-0/Ce-125, S1-Ce-125/Ce-0 and S1-Ce-125/Ce-125, and for 500 ppm nCeO2 were S1-Ce-0/Ce-0, S1-Ce-0/Ce-500, S1-Ce-500/Ce-0 and S1-Ce-500/Ce-500. Agronomic data was collected and plant tissues were harvested for elemental and isotopic analyses. Results showed that S1 exposed plants had accelerated growth and earlier grain formation; however, there was no significant difference in grain yield during harvest. Isotopic analysis revealed that there were differences among treatments in δ13C and δ15N. Relative to control, both 125 and 500 ppm nCeO2 treatments produced grains that had lower δ15N in S1 stressed plants but higher δ13C in S2 treated plants. Surprisingly, elemental analysis showed that nCeO2 treatment reduced uptake of Ce in plants. S1 stressed plants accumulated less Ce compared to S1 unstressed plants. In roots, S1-Ce-125 and S1-Ce-500 had 67 and 39% lower cerium concentration, respectively, compared with S1 unstressed plants. Similarly, nCeO2 treatment at first generation resulted in lower uptake of Fe and Mn in roots. In S1-Ce-125 and S1-Ce-500, the Fe concentration decreased by 51 and 46%, respectively, while Mn decreased by 27 and 21%, respectively, compared to S1 unstressed plants. In summary, the study revealed that previous generation exposure of wheat to nanoceria had carry-over effects on the physiological and agronomic responses of the succeeding generation.