title: Uptake, transport, distribution and Bio-effects of SiO2 nanoparticles in Bt-transgenic cotton.
abstract: BACKGROUND
  SiO2 nanoparticle is one of the most popular nanomaterial which has been used in various fields, such as wastewater treatment, environmental remediation, food processing, industrial and household applications, biomedicine, disease labeling, and biosensor, etc. In agriculture, the use of SiO2 nanoparticles as insecticide, carriers in drug delivery, or in uptake and translocation of nutrient elements, etc., has been given attention. However, the effects of nanoparticles on plants have been seldom studied. In this work, the toxicity of SiO2 nanoparticles and their uptake, transport, distribution and bio-effects have been investigated in Bt-transgenic cotton.
  
  
  METHODS
  The phytotoxic effects of SiO2 nanoparticles were exhibited in Bt-transgenic cotton with different SiO2 concentrations of 0, 10, 100, 500 and 2000 mg.L(-1) for 3 weeks through dry biomasses, nutrient elements, xylem sap, enzymes activities, and hormone concentrations. The uptake and distribution of nanoparticles by the plants were confirmed using transmission electron microscopy (TEM).
  
  
  RESULTS
  The SiO2 nanoparticles decreased significantly the plant height, shoot and root biomasses; the SiO2 nanoparticles also affected the contents of Cu, Mg in shoots and Na in roots of transgenic cotton; and SOD activity and IAA concentration were significantly influenced by SiO2 nanoparticles. In addition, SiO2 nanoparticles were present in the xylem sap and roots as examined by TEM showing that the SiO2 nanoparticles were transported from roots to shoots via xylem sap.
  
  
  CONCLUSIONS
  This is the first report of the transportation of SiO2 nanoparticles via xylem sap within Bt-transgenic cotton. This study provides direct evidence for the bioaccumulation of SiO2 nanoparticles in plants, which shows the potential risks of SiO2 nanoparticles impact on food crops and human health.
authors.affiliation: College of Resources and Environmental Sciences, China Agricultural University, Yuanmingyuan Xilu No.2, Haidian District, Beijing, 100193, China. levannhan.na@gmail.com.|Research Institute for Aquaculture No.1, Tu Son, Bac Ninh, 222260, Viet Nam. levannhan.na@gmail.com.
authors.forename: Van Nhan
authors.initials: VN
authors.lastname: Le
authors.affiliation: College of Resources and Environmental Sciences, China Agricultural University, Yuanmingyuan Xilu No.2, Haidian District, Beijing, 100193, China. ruiyukui@163.com.
authors.forename: Yukui
authors.initials: Y
authors.lastname: Rui
authors.affiliation: College of Resources and Environmental Sciences, China Agricultural University, Yuanmingyuan Xilu No.2, Haidian District, Beijing, 100193, China. guixin@cau.edu.cn.
authors.forename: Xin
authors.initials: X
authors.lastname: Gui
authors.affiliation: College of Resources and Environmental Sciences, China Agricultural University, Yuanmingyuan Xilu No.2, Haidian District, Beijing, 100193, China. lxg1989@126.com.
authors.forename: Xuguang
authors.initials: X
authors.lastname: Li
authors.affiliation: College of Resources and Environmental Sciences, China Agricultural University, Yuanmingyuan Xilu No.2, Haidian District, Beijing, 100193, China. 526563788@qq.com.
authors.forename: Shutong
authors.initials: S
authors.lastname: Liu
authors.affiliation: College of Resources and Environmental Sciences, China Agricultural University, Yuanmingyuan Xilu No.2, Haidian District, Beijing, 100193, China. 1549526114@qq.com.
authors.forename: Yaning
authors.initials: Y
authors.lastname: Han
mesh_terms: D001692:Biological Transport / Q000187:drug effects; D003368:Gossypium / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D046529:Microscopy, Electron, Transmission; D053758:Nanoparticles; D018517:Plant Roots / Q000187:drug effects; D018520:Plant Shoots / Q000187:drug effects; D030821:Plants, Genetically Modified; D012822:Silicon Dioxide / Q000493:pharmacokinetics / Q000494:pharmacology* / Q000633:toxicity; D052584:Xylem / Q000187:drug effects / Q000378:metabolism
chemical_list: D012822:Silicon Dioxide