Effect of surface coating and organic matter on the uptake of CeO2 NPs by corn plants grown in soil: Insight into the uptake mechanism

Abstract

Little is known about the fate, transport, and bioavailability of CeO2 nanoparticles (NPs) in soil. Moreover, there are no reports on the effect of surface coating upon NPs uptake by plants. In this study, Zea mays plants were grown for one month in unenriched and organic soils treated with coated and uncoated CeO2 NPs. In addition, plants were exposed to fluorescein isothiocyanate (FITC)-stained CeO2 NPs and analyzed in a confocal microscope. In organic soil, roots from uncoated and coated NPs at 100, 200, 400, and 800 mg kg−1 had 40, 80, 130, and 260% and 10, 70, 90, and 40% more Ce, respectively, compared to roots from unenriched soil. Conversely, shoots of plants from unenriched soil had significantly more Ce compared with shoots from organic soil. Confocal fluorescence images showed FITC-stained CeO2 NP aggregates in cell walls of epidermis and cortex, suggesting apoplastic pathway. The μXRF results revealed the presence of CeO2 NP aggregates within vascular tissues. To the authors knowledge this is the first report on the effects of surface coating and organic matter on Ce uptake from CeO2 NPs and upon the mechanisms of CeO2 NPs uptake by higher plants

Environmental release, fate and ecotoxicological effects of manufactured ceria nanomaterials

“…The authors did observe ceria in the shoots, including edible tissues, which suggests translocation, but the mechanism and form of element transfer is unknown. Zhao et al 66 observed that after one month of growth in soil, corn roots accumulated significantly greater quantities of alginate coated nanoceria than uncoated particles but no mention was made of toxicity. These authors also noticed that soils with high organic matter generally enhanced the association of nanoceria with roots but reduced the translocation to shoots, regardless of the surface properties of nanoceria.…”

Alginate modifies the physiological impact of CeO2 nanoparticles in corn seedlings cultivated in soil

“…Previous results from our research group have shown that CeO 2 NPs at 2000 mg/L reduced corn (Zea mays) and tomato (Lycopersicon esculentum) germination by 30% and cucumber (Cucumis sativus) germination by 20% (Lopez-Moreno et al, 2010). In a more recent study, we demonstrated that CeO 2 NPs are taken up and stored without change in maize roots (Zhao et al, 2012a). This previous study also revealed that the uptake of CeO 2 NPs by corn plants was affected by soil organic matter content and alginate surface coating (Zhao et al, 2012a).…”

“…In a more recent study, we demonstrated that CeO 2 NPs are taken up and stored without change in maize roots (Zhao et al, 2012a). This previous study also revealed that the uptake of CeO 2 NPs by corn plants was affected by soil organic matter content and alginate surface coating (Zhao et al, 2012a). Alginates are naturally occurring polysaccharides (Chen and Elimelech, 2008;Kantar et al, 2008) that have been used to stabilize NPs for several applications (Li et al, 2008;Chico et al, 2009;Fayaz et al, 2009;dos Santos Silva et al, 2011).…”

Perspectives of cerium nanoparticles use in agriculture

“…Nanoparticles of cerium are able to biotransform in the roots of plants to cerium phosphate [92]. On the other hand, the possibility of transformation of CeO 2 in the roots of cucumber, alfalfa, tomato and corn is denied [37,92].…”