The impact of CeO2 nanoparticles (NPs) on plant physiology and soil microcosm and the underlying mechanism remains unclear to date. This study investigates the effect of CeO2 NPs on plant growth and soil microbial communities in both the rhizosphere of cucumber seedlings and the surrounding bulk soil, with CeCl3 as a comparison to identify the contribution of the particulate and ionic form to the phytotoxicity of CeO2 NPs. The results show that Ce was significantly accumulated in the cucumber tissue after CeO2 NPs exposure. In the roots, 5.3% of the accumulated Ce has transformed to Ce3+. This transformation might take place prior to uptake by the roots since 2.5% of CeO2 NPs was found transformed in the rhizosphere soil. However, the transformation of CeO2 NPs in the bulk soil was negligible, indicating the critical role of rhizosphere chemistry in the transformation. CeO2 NPs treatment induced oxidative stress in the roots, but the biomass of the roots was significantly increased, although the Vitamin C (Vc) content and soluble sugar content were decreased and mineral nutrient contents were altered. The soil enzymatic activity and the microbial community in both rhizosphere and bulk soil samples were altered, with rhizosphere soil showing more prominent changes. CeCl3 treatment induced similar effects although less than CeO2 NPs, suggesting that Ce3+ released from CeO2 NPs contributed to the CeO2 NPs induced impacts on soil health and plant physiology.
Bibliographical noteFunding Information:
This work was financially supported by the National Natural Science Foundation of China (Grant Nos. 12105163 , 11575208 , 11675190 , 11875267 , and 12075262 ), the Natural Science Foundation of Shandong Province (Grant No. ZR2020QD133 ), the Major Research Plan of the Shandong Science Foundation ( ZR2020ZD19 ), and the Ministry of Science and Technology of the People's Republic of China (Grant No. 2016YFA0201604 ). Additional support from EPSRC Impact Acceleration Account Developing Leaders Award ( 1520755 ) is acknowledged.
- CeO NPs
- Cucumber seedlings
- Soil bacterial community
- Soil enzymes
ASJC Scopus subject areas
- Health, Toxicology and Mutagenesis