Xylem- and Phloem-Based Transport of CuO Nanoparticles in Maize (Zea mays L.)

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• 作者：Zhenyu Wang ; Xiaoyan Xie ; Jian Zhao ; Xiaoyun Liu ; Wenqiang Feng ; Jason C. White ; Baoshan Xing
• 刊名：Environmental Science & Technology (ES&T)
• 出版年：2012
• 出版时间：April 17, 2012
• 年：2012
• 卷：46
• 期：8
• 页码：4434-4441
• 全文大小：487K
• 年卷期：v.46,no.8(April 17, 2012)
• ISSN：1520-5851

文摘

This work reports on the toxicity of CuO nanoparticles (NPs) to maize (Zea mays L.) and their transport and redistribution in the plant. CuO NPs (100 mg L^鈥?) had no effect on germination, but inhibited the growth of maize seedlings; in comparison the dissolved Cu²⁺ ions and CuO bulk particles had no obvious effect on maize growth. CuO NPs were present in xylem sap as examined by transmission electron microscopy (TEM) and energy dispersive spectroscopy (EDS), showing that CuO NPs were transported from roots to shoots via xylem. Split-root experiments and high-resolution TEM observation further showed that CuO NPs could translocate from shoots back to roots via phloem. During this translocation, CuO NPs could be reduced from Cu (II) to Cu (I). To our knowledge, this is the first report of root鈥搒hoot鈥搑oot redistribution of CuO NPs within maize. The current study provides direct evidence for the bioaccumulation and biotransformation of CuO NPs (20鈥?0 nm) in maize, which has significant implications on the potential risk of NPs and food safety.