Exposure of Iron Nanoparticles to Arabidopsis thaliana Enhances Root Elongation by Triggering Cell Wall Loosening

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• 作者：Jae-Hwan Kim ; Yongjik Lee ; Eun-Ju Kim ; Sungmin Gu ; Eun Ju Sohn ; Young Sook Seo ; Hyun Joo An ; Yoon-Seok Chang
• 刊名：Environmental Science & Technology
• 出版年：2014
• 出版时间：March 18, 2014
• 年：2014
• 卷：48
• 期：6
• 页码：3477-3485
• 全文大小：572K
• 年卷期：v.48,no.6(March 18, 2014)
• ISSN：1520-5851

文摘

In this study, we investigated the effect of nZVI on plant root elongation in Arabidopsis thaliana and showed, for the first time, that nZVI enhanced root elongation by inducing OH radical-induced cell wall loosening. Exposure of plants to 0.5 g/L nZVI enhanced root elongation by 150鈥?00% over that in the control, and further mechanistic studies showed that this occurred via nZVI-mediated OH radical-induced cell wall loosening. The oxidation capacity of nZVI, leading to release of H₂O₂, allowed it to cause OH radical-induced cell wall loosening in roots. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometers (MALDI-TOFMS)-based analysis clearly revealed that pectin-polysaccharides in roots were degraded; they are one of the main matrix-polysaccharide-connecting and load-bearing polymers in cell walls. Rapid root elongation led to structural changes in root cell walls: reduction of cell wall thickness and a bias on the orientation of cellulose microfibrils. Additionally, the asymmetrical distribution of tensional strength resulted from the OH radical-induced cell wall loosening enhanced endocytosis. These findings emphasize that OH radical-induced cell wall loosening is important for mechanical regulation of the cell wall and provide new insights into the cellular responses of plants exposed to reactive metal nanoparticles.