Gong Chenchen, Wang Linghao, Li Xiaolu, Wang Hongsen, Jiang Yuxin, Wang Wenxing
College of Life and Health Sciences, Northeastern University Shenyang 110819 China
RSC Adv. 2019 Sep 3;9(47):27720-27731. doi: 10.1039/c9ra04672k. eCollection 2019 Aug 29.
The potential risks of rare-earth nanoparticles (RENPs) to plants in the environment are attracting increasing attention due to their wide-spread application. In this regard, little is known about the effects of YO NPs as an important member of RENPs on crop plants. Seed germination is vulnerable to environmental stress, which determines the growth and yield of crops. Here, maize seeds were exposed to a YO NP suspension (0-500 mg L) in the dark for 6 days. It was found that the YO NPs had no significant effect on the germination rates (>93%) in all treatments, but they could reduce seed vitality, delay germination, and inhibit seedling growth in a dose-dependent manner. Further, the inhibition effect of YO NPs on root elongation was much stronger than that on shoot elongation. Meanwhile, the activities of peroxidase (POD) and catalase (CAT) in shoots were enhanced with the increase in the YO NP concentration. A high-concentration (≥300 mg L) of YO NPs induced a significant increase in the malondialdehyde (MDA) level in shoots compared to the control, indicating that the membrane lipid peroxidation and permeability were enhanced. H NMR-based analysis showed that the polar metabolic profiles were altered significantly after treatment with 0, 10, and 500 mg L of YO NPs, but there was no marked alteration observed for the non-polar metabolic profiles. The polar metabolites (, sugars, amino acids, and most organic acids) showed a dose-dependent increase to YO NP stress, indicating that the metabolic pathways of carbohydrate metabolism, the tricarboxylic acid cycle (TCA), and amino acid synthesis were disturbed. There were significantly positive correlations found among the metabolites related with the antioxidant response and osmotic adjustment. The simultaneous accumulation of these metabolites possibly indicated the adaptation of the seedlings to stress at the cost of retarding glycolysis, TCA, and protein synthesis. The retarded effects finally inhibited the apparent growth of the seedlings. These findings reveal the phytotoxicity of YO NPs and provide physiological and biochemical and molecular-scale perspectives on the response of seedlings to stress.
由于稀土纳米颗粒（RENPs）的广泛应用，其在环境中对植物的潜在风险正受到越来越多的关注。在这方面，作为RENPs重要成员的氧化钇纳米颗粒（YO NPs）对农作物的影响却知之甚少。种子萌发易受环境胁迫影响，而环境胁迫决定着作物的生长和产量。在此，将玉米种子在黑暗中暴露于YO NP悬浮液（0 - 500毫克/升）中6天。结果发现，在所有处理中YO NPs对发芽率（>93%）没有显著影响，但它们会降低种子活力、延迟发芽，并以剂量依赖的方式抑制幼苗生长。此外，YO NPs对根伸长的抑制作用比对地上部伸长的抑制作用要强得多。同时，地上部过氧化物酶（POD）和过氧化氢酶（CAT）的活性随着YO NP浓度的增加而增强。与对照相比，高浓度（≥300毫克/升）的YO NPs诱导地上部丙二醛（MDA）水平显著升高，表明膜脂过氧化和通透性增强。基于核磁共振氢谱（1H NMR）的分析表明，用0、10和500毫克/升的YO NPs处理后，极性代谢谱发生了显著变化，但非极性代谢谱未观察到明显改变。极性代谢物（如糖类、氨基酸和大多数有机酸）对YO NP胁迫呈剂量依赖性增加，表明碳水化合物代谢、三羧酸循环（TCA）和氨基酸合成的代谢途径受到干扰。与抗氧化反应和渗透调节相关的代谢物之间存在显著正相关。这些代谢物的同时积累可能表明幼苗以延缓糖酵解、TCA和蛋白质合成的代价来适应胁迫。这些抑制作用最终抑制了幼苗的表观生长。这些发现揭示了YO NPs的植物毒性，并为幼苗对胁迫的响应提供了生理生化和分子水平的视角。
