Biochar-assisted transformation of engineered-cerium oxide nanoparticles: Effect on wheat growth, photosynthetic traits and cerium accumulation (original) (raw)
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To investigate how the physicochemical properties of nanoparticles (NPs) affect their biological and toxicological effects, we evaluated the phytotoxicity of CeO2 and La2O3 NPs to cucumber (Cucumis sativus) plants and tried to clarify the relation between physicochemical properties of NPs and their behaviors. CeO2 NPs had no phytotoxicity to cucumber at all tested concentrations, while La2O3 NPs showed significant inhibition on root elongation (2 mg/L), shoot elongation (at 2000 mg/L), root biomass (2 mg/L), and shoot biomass (20 mg/L), as well as induced more reactive oxygen species and cell death in roots (2000 mg/L). The different distribution and speciation of Ce and La in plants were determined by synchrotron-based micro X-ray fluorescence microscopy and X-ray absorption spectroscopy. In the aerial parts, all of La was combined with phosphate or carboxylic group, while a fraction of Ce was changed to Ce(III)–carboxyl complexes, implying that La2O3 acted as its ionic form, while CeO2 displayed the behavior of particles or particle–ion mixtures. The higher dissolution of La2O3 than CeO2 NPs might be the reason for their significant difference in phytotoxicity and transporting behaviors in cucumbers. To our knowledge, this is the first detailed study of the relation between the level of dissolution of NPs and their behaviors in plant systems.
The Science of the total environment, 2016
Soil organic matter plays a major role in determining the fate of the engineered nanomaterials (ENMs) in the soil matrix and effects on the residing plants. In this study, kidney bean plants were grown in soils varying in organic matter content and amended with 0-500mg/kg cerium oxide nanoparticles (nano-CeO2) under greenhouse condition. After 52days of exposure, cerium accumulation in tissues, plant growth and physiological parameters including photosynthetic pigments (chlorophylls and carotenoids), net photosynthesis rate, transpiration rate, and stomatal conductance were recorded. Additionally, catalase and ascorbate peroxidase activities were measured to evaluate oxidative stress in the tissues. The translocation factor of cerium in the nano-CeO2 exposed plants grown in organic matter enriched soil (OMES) was twice as the plants grown in low organic matter soil (LOMS). Although the leaf cover area increased by 65-111% with increasing nano-CeO2 concentration in LOMS, the effect o...
Journal of Hazardous Materials, 2019
This study investigated the effects of third generation exposure to cerium oxide nanoparticles (CeO 2-NPs) on biomass, elemental and 15 N uptake, and fatty acid contents 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 CeO 2-NPs per kg soil treatment were cultivated for third year in soil amended with 0 or 500 mg CeO 2-NPs per kg soil. The results showed that parental and current exposures to CeO 2-NPs increased the root biomass in daughter plants with greater magnitude of increase at low N than high N. When wheat received CeO 2-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 δ 15 N ratios, previously shown to be altered by CeO 2-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 CeO 2-NPs. The
Plants, 2019
Reports about the influence of cerium-oxide nanoparticles (nCeO 2) on plants are contradictory due to their positive and negative effects on plants. Surface modification may affect the interaction of nCeO 2 with the environment, and hence its availability to plants. In this study, the uncoated and glucose-, levan-, and pullulan-coated nCeO 2 were synthesized and characterized. The aim was to determine whether nontoxic carbohydrates alter the effect of nCeO 2 on the seed germination, plant growth, and metabolism of wheat and pea. We applied 200 mgL −1 of nCeO 2 on plants during germination (Ger treatment) or three week-growth (Gro treatment) in hydroponics. The plant response to nCeO 2 was studied by measuring changes in Ce concentration, total antioxidative activity (TAA), total phenolic content (TPC), and phenolic profile. Our results generally revealed higher Ce concentration in plants after the treatment with coated nanoparticles compared to uncoated ones. Considering all obtained results, Ger treatment had a stronger impact on the later stages of plant development than Gro treatment. The Ger treatment had a stronger impact on TPC and plant elongation, whereas Gro treatment affected more TAA and phenolic profile. Among nanoparticles, levan-coated nCeO 2 had the strongest and positive impact on tested plants. Wheat showed higher sensitivity to all treatments.
Italian Journal of Agronomy, 2016
In recent years, remarkable progress has been made in developing nanotechnology. This has led to a fast-growth of commercial applications, which involve the use of a great variety of manufactured nanomaterials. Given that, soils and sediments are the ultimate sinks of engineered nanomaterials (ENMs), they can be taken up by microorganisms, nematodes, earthworms or plants, and potentially transferred to the food chain up to animals and humans. However, the reactions of the biota exposed to ENMs of different size are still not well understood. Very few studies on nanoparticles-plant interactions have been published, so far. In this paper we report the results of multiple experiments carried out to study the effects of cerium oxide nanoparticles (nCeO2) on Hordeum vulgare. The nCeO2 powder and suspension were characterised for specific surface area, z-average size, and zeta potential. Germinating caryopses and barley seedlings were exposed to an aqueous dispersion of nCeO2 at respectiv...
Environmental Science and Pollution Research, 2015
A soil microcosm study was performed to examine the impacts of cerium oxide nanoparticles (nCeO 2 ) on the physiology, productivity, and macromolecular composition of barley (Hordeum vulgare L.). The plants were cultivated in soil treated with nCeO 2 at 0, 125, 250, and 500 mg kg −1 (control, nCeO 2 -L, nCeO 2 -M, and nCeO 2 -H, respectively). Accumulation of Ce in leaves/grains and its effects on plant stress and nutrient loading were analyzed. The data revealed that nCeO 2 -H promoted plant development resulting in 331 % increase in shoot biomass compared with the control. nCeO 2 treatment modified the stress levels in leaves without apparent signs of toxicity. However, plants exposed to nCeO 2 -H treatment did not form grains. Compared with control, nCeO 2 -M enhanced grain Ce accumulation by as much as 294 % which was accompanied by remarkable increases in P, K, Ca, Mg, S, Fe, Zn, Cu, and Al. Likewise, nCeO 2 -M enhanced the methionine, aspartic acid, threonine, tyrosine, arginine, and linolenic acid contents in the grains by up to 617, 31, 58, 141, 378, and 2.47 % respectively, compared with the rest of the treatments. The findings illustrate the beneficial and harmful effects of nanoceria in barley.
Journal of Agricultural and Food Chemistry
The implications of engineered nanomaterials on crop productivity and food quality are not yet well understood. The impacts of cerium oxide nanoparticles (nCeO2) on growth and yield attributes and nutritional composition in wheat (Triticum aestivum L.) were examined. Wheat was cultivated to grain production in soil amended with 0, 125, 250, and 500 mg nCeO2/kg (control, nCeO2-L, nCeO2-M, and nCeO2-H, respectively). At harvest, grains and tissues were analyzed for mineral, fatty acids, and amino acids contents. Results showed that, relative to the control, nCeO2-H improved plant growth, shoot biomass, and grain yield by 9.0, 12.7, and 36.6%, respectively. Ce accumulation in roots increased at increased nCeO2 concentration but did not change across treatments in leaves, hull and grains indicating a lack of Ce transport to the aboveground tissues. nCeO2 modified the S and Mn storage in grains. nCeO2-L modified the amino acids composition, and increased the linolenic acid by up to 6.17%...
Environmental science & technology, 2017
The ISO-standardized RHIZOtest is used here for the first time to decipher how plant species, soil properties, and physical-chemical properties of the nanoparticles and their transformation regulate the phytoavailability of nanoparticles. Two plants, tomato and fescue, were exposed to two soils with contrasted properties: a sandy soil poor in organic matter and a clay soil rich in organic matter, both contaminated with 1, 15, and 50 mg·kg(-1) of dissolved Ce2(SO4)3, bare and citrate-coated CeO2 nanoparticles. All the results demonstrate that two antagonistic soil properties controlled Ce uptake. The clay fraction enhanced the retention of the CeO2 nanoparticles and hence reduced Ce uptake, whereas the organic matter content enhanced Ce uptake. Moreover, in the soil poor in organic matter, the organic citrate coating significantly enhanced the phytoavailability of the cerium by forming smaller aggregates thereby facilitating the transport of nanoparticles to the roots. By getting rid...
Biotransformation of ceria nanoparticles in cucumber plants
Biotransformation is a critical factor that may modify the toxicity, behavior, and fate of engineered nanoparticles in the environment. CeO2 nanoparticles (NPs) are generally recognized as stable under environmental and biological conditions. The present study aims to investigate the biotransformation of CeO2 NPs in plant systems. Transmission electron microscopy (TEM) images show needlelike clusters on the epidermis and in the intercellular spaces of cucumber roots after a treatment with 2000 mg/L CeO2 NPs for 21 days. By using a soft X-ray scanning transmission microscopy (STXM) technique, the needlelike clusters were verified to be CePO4. Near edge X-ray absorption fine structure (XANES) spectra show that Ce presented in the roots as CeO2 and CePO4 while in the shoots as CeO2 and cerium carboxylates. Simulated studies indicate that reducing substances (e.g., ascorbic acids) played a key role in the transformation process and organic acids (e.g., citric acids) can promote particle dissolution. We speculate that CeO2 NPs were first absorbed on the root surfaces and partially dissolved with the assistance of the organic acids and reducing substances excreted by the roots. The released Ce(III) ions were precipitated on the root surfaces and in intercellular spaces with phosphate, or form complexes with carboxyl compounds during translocation to the shoots. To the best of our knowledge, this is the first report confirming the biotransformation and in-depth exploring the translocation process of CeO2 NPs in plants.
Biotransformation of Ceria Nanoparticles in Cucumber Plants.pdf
Biotransformation is a critical factor that may modify the toxicity, behavior, and fate of engineered nanoparticles in the environment. CeO2 nanoparticles (NPs) are generally recognized as stable under environmental and biological conditions. The present study aims to investigate the biotransformation of CeO2 NPs in plant systems. Transmission electron microscopy (TEM) images show needlelike clusters on the epidermis and in the intercellular spaces of cucumber roots after a treatment with 2000 mg/L CeO2 NPs for 21 days. By using a soft X-ray scanning transmission microscopy (STXM) technique, the needlelike clusters were verified to be CePO4. Near edge X-ray absorption fine structure (XANES) spectra show that Ce presented in the roots as CeO2 and CePO4 while in the shoots as CeO2 and cerium carboxylates. Simulated studies indicate that reducing substances (e.g., ascorbic acids) played a key role in the transformation process and organic acids (e.g., citric acids) can promote particle dissolution. We speculate that CeO2 NPs were first absorbed on the root surfaces and partially dissolved with the assistance of the organic acids and reducing substances excreted by the roots. The released Ce(III) ions were precipitated on the root surfaces and in intercellular spaces with phosphate, or form complexes with carboxyl compounds during translocation to the shoots. To the best of our knowledge, this is the first report confirming the biotransformation and in-depth exploring the translocation process of CeO2 NPs in plants.