Divergent responses and ecological risks of wheat (Triticum aestivum L.) to cerium oxide nanoparticles in different soil types.

Cerium oxide nanoparticles (nCeO), as a common component for sustainable agriculture, have been broadly investigated due to their potential threat to the soil biodiversity and health. However, few studies considered the impacts of soil types on response of ecotoxicity of nCeO to plants. This study aimed to explore the effects of soil properties on ecological response of nCeO to wheat (Triticum aestivum L.) and assess the ecological risks of nCeO (0-1000 mg/kg) in red soil, yellow-brown soil, and brown soil by applying a multi-biomarker approach. The results showed that the clay content had the extremely significant correlation with acid solute fraction Ce in soil. Ce accumulation in wheat largely depended on acid-soluble fraction Ce, but not the total Ce. Both urease and invertase activities were highest in brown soil among the three soils, after exposure to diverse concentration nCeO. Although wheat has a stronger antioxidant capacity in red soil, integrated biomarker response index proved that nCeO showed least toxicity to wheat in brown soil (IBRv2 = 34.3) among the three soils. These results indicated that the toxicity level of nCeO to wheat was not only related to contaminated concentration, but also greatly depended on soil properties. The soil types are important factors governing ecological risk of nCeO in soil, which needs to be adequately assessed and properly controlled.