Phytotoxicity and biotransformation of La2O3 nanoparticles in a terrestrial plant cucumber (Cucumis sativus)

• Published in: Nanotoxicology 2011-12, Vol.5 (4), p.743-753
• Main Authors: Ma, Yuhui, He, Xiao, Zhang, Peng, Zhang, Zhiyong, Guo, Zhi, Tai, Renzhong, Xu, Zijian, Zhang, Lijuan, Ding, Yayun, Zhao, Yuliang, Chai, Zhifang
• Format: Article
• Language: English
• Subjects: Analysis of Variance; Biotransformation; Cucumis sativus - drug effects; Cucumis sativus - metabolism; dissolution; Histocytochemistry; Lanthanum - chemistry; Lanthanum - metabolism; Lanthanum - toxicity; Metal Nanoparticles - chemistry; Metal Nanoparticles - toxicity; nanoparticles; Oxides - chemistry; Oxides - metabolism; Oxides - toxicity; phytotoxicity; Plant Roots - chemistry; Plant Roots - cytology; Plant Roots - drug effects
• ISSN: 1743-5390; 1743-5404
• DOI: 10.3109/17435390.2010.545487

Abstract With the increasing applications of metal-based nanoparticles in various commercial products, it is necessary to address their environmental fate and potential toxicity. In this work, we assessed the phytotoxicity of lanthanum oxide (La2O3) NPs to cucumber plants and determined its distribution and biotransformation in roots by TEM and EDS, as well as STXM and NEXAFS. LaCl3 was also studied as a reference toxicant. La2O3 NPs and LaCl3 were both transformed to needle-like LaPO4 nanoclusters in the intercellular regions of the cucumber roots. In vitro experiments demonstrated that the dissolution of La2O3 NPs was significantly enhanced by acetic acid. Accordingly, we proposed that the dissolution of NPs at the root surface induced by the organic acids extruded from root cells played an important role in the phytotoxicity of La2O3 NPs. The reactions of active NPs at the nano-bio interface should be taken into account when studying the toxicity of dissolvable metal-based nanoparticles.