title: Phytotoxicity of ZnO nanoparticles and the released Zn(II) ion to corn (Zea mays L.) and cucumber (Cucumis sativus L.) during germination.
abstract: Toxicity of engineered nanoparticles on organisms is of concern worldwide due to their extensive use and unique properties. The impacts of ZnO nanoparticles (ZnO NPs) on seed germination and root elongation of corn (Zea mays L.) and cucumber (Cucumis sativus L.) were investigated in this study. The role of seed coats of corn in the mitigation toxicity of nanoparticles was also evaluated. ZnO NPs (1,000 mg L(-1)) reduced root length of corn and cucumber by 17 % (p < 0.05) and 51 % (p < 0.05), respectively, but exhibited no effects on germination. In comparison with Zn(2+), toxicity of ZnO NPs on the root elongation of corn could be attributed to the nanoparticulate ZnO, while released Zn ion from ZnO could solely contribute to the inhibition of root elongation of cucumber. Zn uptake in corn exposed to ZnO NPs during germination was much higher than that in corn exposed to Zn(2+), whereas Zn uptake in cucumber was significantly correlated with soluble Zn in suspension. It could be inferred that Zn was taken up by corn and cucumber mainly in the form of ZnO NPs and soluble Zn, respectively. Transmission electron microscope confirmed the uptake of ZnO NPs into root of corn. Although isolation of the seed coats might not be the principal factor that achieved avoidance from toxicity on germination, seed coats of corn were found to mitigate the toxicity of ZnO NPs on root elongation and prevent approximately half of the Zn from entering into root and endosperm.
authors: Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Sciences, Nanjing, 210008, China.
authors: Ruichang
authors: R
authors: Zhang
authors: Haibo
authors: H
authors: Zhang
authors: Chen
authors: C
authors: Tu
authors: Xuefeng
authors: X
authors: Hu
authors: Lianzhen
authors: L
authors: Li
authors: Yongming
authors: Y
authors: Luo
authors: Peter
authors: P
authors: Christie
mesh_terms: D018553:Cucumis sativus / Q000187:drug effects* / Q000254:growth & development; D018525:Germination / Q000187:drug effects*; D053758:Nanoparticles / Q000737:chemistry*; D018517:Plant Roots / Q000187:drug effects / Q000254:growth & development; D012639:Seeds / Q000187:drug effects / Q000254:growth & development; D003313:Zea mays / Q000187:drug effects* / Q000254:growth & development; D015032:Zinc / Q000737:chemistry / Q000633:toxicity*; D015034:Zinc Oxide / Q000737:chemistry / Q000633:toxicity*
chemical_list: D015032:Zinc; D015034:Zinc Oxide