Salts affect the interaction of ZnO or CuO nanoparticles with wheat.
Exposure to nanoparticles (NPs) that release metals with potential phytotoxicity could pose problems in agriculture. The authors of the present study used growth in a model growth matrix, sand, to examine the influence of 5 mmol/kg of Na, K, or Ca (added as Cl salts) and root exudates on transformation and changes to the bioactivity of copper(II) oxide (CuO) and zinc oxide (ZnO) NPs on wheat. These salt levels are found in saline agricultural soils. After 14 d of seedling growth, particles with crystallinity typical of CuO or ZnO remained in the aqueous fraction from the sand; particles had negative surface charges that differed with NP type and salt, but salt did not alter particle agglomeration. Reduction in shoot and root elongation and lateral root induction by ZnO NPs were mitigated by all salts. However, whereas Na and K promoted Zn loading into shoots, Ca reduced loading, suggesting that competition with Zn ions for uptake occurred. With CuO NPs, plant growth and loading was modified equally by all salts, consistent with major interaction with the plant with CuO rather than Cu ions. Thus, for both NPs, loading into plant tissues was not solely dependent on ion solubility. These findings indicated that salts in agricultural soils could modify the phytotoxicity of NPs.
Department of Biology, Utah State University, Logan, Utah, USA.
Jacob
J
Stewart
Department of Biology, Utah State University, Logan, Utah, USA.
Trevor
T
Hansen
Utah Water Research Laboratory, Utah State University, Logan, Utah, USA.
Joan E
JE
McLean
Utah Water Research Laboratory, Utah State University, Logan, Utah, USA.
Paul
P
McManus
Chemistry and Biochemistry Department, Utah State University, Logan, Utah, USA.
Siddhartha
S
Das
Biological Engineering Department, Utah State University, Logan, Utah, USA.
David W
DW
Britt
Department of Biology, Utah State University, Logan, Utah, USA.
Anne J
AJ
Anderson
Department of Biology, Utah State University, Logan, Utah, USA.
Christian O
CO
Dimkpa
D003300:Copper / Q000737:chemistry*; D007477:Ions / Q000737:chemistry; D053768:Metal Nanoparticles / Q000737:chemistry / Q000633:toxicity*; D008670:Metals / Q000737:chemistry / Q000378:metabolism; D018625:Microscopy, Atomic Force; D010316:Particle Size; D018517:Plant Roots / Q000737:chemistry / Q000187:drug effects / Q000254:growth & development; D018520:Plant Shoots / Q000737:chemistry / Q000187:drug effects / Q000254:growth & development; D012492:Salts / Q000737:chemistry* / Q000494:pharmacology; D036226:Seedlings / Q000187:drug effects / Q000254:growth & development; D012987:Soil / Q000737:chemistry; D014908:Triticum / Q000187:drug effects* / Q000254:growth & development; D014867:Water / Q000737:chemistry; D015034:Zinc Oxide / Q000737:chemistry*
D007477:Ions; D008670:Metals; D012492:Salts; D012987:Soil; D014867:Water; D003300:Copper; D015034:Zinc Oxide; C030973:cupric oxide
Bioaccumulation; Dissolution; Lateral root proliferation; Metal oxide nanoparticles; Salts; Wheat