Whether zinc nanoparticles (NPs) are phytotoxic or beneficial to plants remains controversial because of limited research. In this study, we investigated the effect of various concentrations of zinc oxide (ZnO) NPs (0, 1, 5, 20, 100, and 1000 mg kg −1 of soil) on lettuce ( Lactuca sativa L.) and carrot ( Daucus carota subsp. sativus ) plants. Plants of both crop species grown in ZnO NPs showed a significant increase in biomass compared with control plants (0 mg kg −1 ), except for lettuce plants grown in the highest concentration of NPs (1000 mg kg −1 ), indicating that ZnO NPs acted as a fertilizer. Additionally, control plants showed lower levels of chlorophyll and zinc, magnesium, and potassium than plants grown in ZnO NPs, except for the Mg content of carrot roots grown in 20 mg kg −1 ZnO NPs. Plants of both species grown in 5 and 20 mg kg −1 ZnO NPs showed the highest concentration of nitrogen. Negative effects of ZnO NPs were evident only in lettuce plants grown in 1000 mg kg −1 ZnO NPs, which is more likely an exaggerated level rather than an environmentally realistic concentration. Thus, our data suggest that ZnO NPs are a fertilizer for crop plants and would increase crop productivity when used carefully.

中文翻译：

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氧化锌纳米颗粒：一种潜在的低毒园艺作物微量营养素肥料

由于研究有限，锌纳米颗粒 (NPs) 是否对植物具有植物毒性或有益作用仍然存在争议。在这项研究中，我们研究了不同浓度的氧化锌 (ZnO) NPs（0、1、5、20、100 和 1000 mg kg -1 土壤）对生菜（ Lactuca sativa L.）和胡萝卜（ Daucus carota subsp. sativus ) 植物。与对照植物 (0 mg kg -1 ) 相比，在 ZnO NPs 中生长的两种作物的植物显示出生物量的显着增加，除了在最高浓度 NPs (1000 mg kg -1 ) 中生长的生菜植物外，表明 ZnO NPs起到了肥料的作用。此外，除了生长在 20 mg kg -1 ZnO NPs 中的胡萝卜根的镁含量外，对照植物的叶绿素和锌、镁和钾含量低于在 ZnO NPs 中生长的植物。在 5 和 20 mg kg -1 ZnO NPs 中生长的两个物种的植物表现出最高的氮浓度。ZnO NPs 的负面影响仅在 1000 mg kg -1 ZnO NPs 中生长的生菜植物中明显，这更可能是夸大的水平，而不是环境现实的浓度。因此，我们的数据表明，ZnO NPs 是作物的肥料，如果谨慎使用，会提高作物生产力。