The increase in global production of nanomaterials has raised concern as to their possible effects on plants that could ultimately affect the human population. The effects on the hydroponic growth of wheatgrass of four types of nanomaterials were studied: raw-single walled carbon nanotubes (SWCNTs), purified-SWCNTs, multi walled carbon nanotubes (MWCNTs), and iron oxide nanoparticles (n-FeO_x) as a model of the catalyst residue typically present in CNTs. The germination rate (GR), mean germination time (MGT), shoot length, and a visual score of the plants' growth were determined for wheatgrass over the course of two weeks as a function of exposure to the nanomaterials dispersed in either water or THF (as well as appropriate controls). Raw-SWCNTs, MWCNTs, and n-FeO_x show little impact suggesting that the catalyst residue (iron oxide) present in CNTs has little effect. Exposure to purified-SWCNTs dispersed in water shows increased GR (and shoot length), while wheatgrass exposed to purified-SWCNT dispersed in THF had retarded GR, suggesting that SWCNTs act as a carrier for adsorbed organic solvents whose effects are detrimental. A similar but lesser effect was observed for MWCNTs. Interestingly raw-SWCNTs showed no solvent effect, suggesting that the reduction of hydrophobicity of the SWCNTs through functionalisation enables the adsorption and subsequent release of harmful organic solvents. The positive effect of purified SWCNTs when dispersed in water is likely a function of their highly hydrophobic nature facilitating enhanced uptake of water.

中文翻译：

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生并纯化碳纳米管和氧化铁纳米颗粒对小麦草从普通小麦（子叶制备的生长小麦）†

全球纳米材料产量的增长引起了人们的关注，即纳米材料对植物的影响可能最终影响人类。研究了四种类型的纳米材料对小麦草水培生长的影响：原始单壁碳纳米管（SWCNT），纯化单壁碳纳米管，多壁碳纳米管（MWCNT）和氧化铁纳米颗粒（n -FeO _x）。碳纳米管中通常存在的催化剂残留物的模型。确定了两周内小麦草的发芽率（GR），平均发芽时间（MGT），枝条长度和植物生长的视觉分数，这取决于对分散在水或THF中的纳米材料的暴露程度（以及适当的控件）。原始SWCNT，MWCNT和n-FeO _x几乎没有影响，表明存在于CNT中的催化剂残留物（氧化铁）影响很小。暴露于分散在水中的纯净SWCNTs会显示GR（和茎长）增加，而暴露于分散在THF中的纯净SWCNT的小麦草的GR会延迟，这表明SWCNTs充当了吸附有机溶剂的载体，其影响是有害的。对于MWCNT，观察到类似但较小的作用。有趣的是，原始SWCNT没有显示出溶剂作用，这表明通过官能化减少SWCNT的疏水性可以吸附有害的有机溶剂并随后释放。纯化的SWCNT分散在水中时的积极作用可能是其高度疏水性的功能，有利于增加水的吸收。