This pot experiment grew barley to maturity in soil amended with cerium oxide or titanium oxide nanoparticles at 500 and 1000 mg/kg and measured cerium, nutrients, starch and amino acids in the kernels. Kernel cerium under nanoparticle treatment did not differ significantly from the control, but the nanoparticles shifted kernel composition, including lower amylose and higher crude protein.
Key numbers
- Kernel cerium (mean plus or minus SE, mg/kg dry weight, n = 5): control 0.50 plus or minus 0.20; 500 mg/kg cerium oxide 1.03 plus or minus 0.84; 1000 mg/kg cerium oxide 0.70 plus or minus 0.37; no significant differences (Table 5, p. 6).
- ICP-MS method detection limit for cerium 1 µg/L in digest solution (p. 4).
- Both nanoparticle types reduced amylose by about 21%; lysine rose by 51% and proline by 37% (abstract).
- Kernel manganese correlated with kernel cerium under cerium oxide treatments (r = 0.859, P < 0.001) (Section 3.6).
Methods (brief)
Barley was grown in pots of a sandy-clay soil (pH 7.44) amended with commercial cerium oxide nanoparticles (about 23 nm) or titanium oxide nanoparticles. Kernels were harvested at ripening, digested in hydrochloric and nitric acid, and analyzed by ICP-AES for nutrients and ICP-MS for total cerium, with tomato leaves reference material 1573a (average recovery 97%).
Evidence fitness
Supports the finding that soil cerium oxide nanoparticles at high dose did not measurably raise cerium in barley grain under these conditions, and gives a control-grain cerium value for this Italian soil. It does not represent field conditions, other cereals, or market grain.
Limitations
Five pots per treatment with high variability (SE about 45% of the mean); single soil and cultivar; total cerium only, no form or particle analysis in grain.
Related evidence
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