Department of Plant Biology, Faculty of Science and Informatics, University of Szeged, H-6726, Szeged, Közép fasor 52., Hungary.
Department of Applied and Environmental Chemistry, Faculty of Science and Informatics, University of Szeged, H-6720, Szeged, Rerrich Bela ter 1., Hungary.
Ecotoxicol Environ Saf. 2020 Dec 15;206:111158. doi: 10.1016/j.ecoenv.2020.111158. Epub 2020 Aug 28.
Cell wall-associated defence against zinc oxide nanoparticles (ZnO NPs) as well as nitro-oxidative signalling and its consequences in plants are poorly examined. Therefore, this study compares the effect of chemically synthetized ZnO NPs (~45 nm, 25 or 100 mg/L) on Brassica napus and Brassica juncea seedlings. The effects on root biomass and viability suggest that B. napus is more tolerant to ZnO NP exposure relative to B. juncea. This may be due to the lack of Zn ion accumulation in the roots, which is related to the increase in the amount of lignin, suberin, pectin and in peroxidase activity in the roots of B. napus. TEM results indicate that root cell walls of 25 mg/L ZnO NP-treated B. napus may bind Zn ions. Additionally, callose accumulation possibly contribute to root shortening in both Brassica species as the effect of 100 mg/L ZnO NPs. Further results suggest that in the roots of the relatively sensitive B. juncea the levels of superoxide radical, hydrogen peroxide, hydrogen sulfide, nitric oxide, peroxinitrite and S-nitrosoglutathione increased as the effect of high ZnO NP concentration meaning that ZnO NP intensifies nitro-oxidative signalling. In B. napus; however, reactive oxygen species signalling was intensified, but reactive nitrogen species signalling wasn't activated by ZnO NPs. Collectively, these results indicate that ZnO NPs induce cell wall remodeling which may be associated with ZnO NP tolerance. Furthermore, plant tolerance against ZnO NPs is associated rather with nitrosative signalling than oxidative modifications.
细胞壁与氧化锌纳米颗粒（ZnO NPs）的防御作用，以及氮氧化物信号及其在植物中的后果，都没有得到充分的研究。因此，本研究比较了化学合成的 ZnO NPs（~45nm，25 或 100mg/L）对油菜和芥菜幼苗的影响。对根生物量和活力的影响表明，相对于芥菜，油菜对 ZnO NP 暴露更具耐受性。这可能是由于根中锌离子的积累缺乏，这与油菜根中木质素、角质、果胶和过氧化物酶活性的增加有关。TEM 结果表明，25mg/L ZnO NP 处理的油菜根细胞壁可能结合了 Zn 离子。此外，由于 100mg/L ZnO NPs 的作用，-callose 的积累可能导致两种芥菜物种的根缩短。进一步的结果表明，在相对敏感的芥菜根中，超氧自由基、过氧化氢、硫化氢、一氧化氮、过氧亚硝酸盐和 S-亚硝基谷胱甘肽的水平随着 ZnO NP 浓度的增加而增加，这意味着 ZnO NP 加剧了氮氧化物信号。然而，在油菜中，活性氧信号被强化，但活性氮信号没有被 ZnO NPs 激活。总的来说，这些结果表明，ZnO NPs 诱导细胞壁重塑，这可能与 ZnO NP 耐受性有关。此外，植物对 ZnO NPs 的耐受性与其说是与氧化修饰有关，不如说是与氮氧化物信号有关。
