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纳米氧化锌(ZnO-NPs)是目前最常见的工程纳米颗粒之一,广泛应用于各类产品中,对生态环境有潜在影响。为了阐明ZnO-NPs对土壤微生物酶活性的影响,探讨其作用机制及剂量-效应关系,通过微宇宙实验,分别建立了纯菌(微杆菌)培养体系和土壤培养体系,对不同浓度ZnO-NPs暴露条件下微生物的荧光素二乙酸酯水解酶(FDAH)活性进行了测定,在纯菌培养体系中也测定了脱氢酶(DH)活性。结果显示,与不含ZnO-NPs的对照相比,培养液中ZnO-NPs浓度为1、5、10 mg·L-1时,对微杆菌的FDAH和DH活性均产生了显著抑制,抑制率分别为22.5%、61.2%、62.3%和27.8%、44.8%、44.8%。ZnO-NPs附着在微杆菌膜上,有些进入菌体内,对菌体造成了氧化损伤。土壤中ZnO-NPs浓度为5mg·g-1和10 mg·g-1时,FDAH活性显著低于不含ZnO-NPs的对照土壤(P=0.007和P=0.008)。土壤中ZnO-NPs浓度为1mg·g-1时,FDAH活性与对照无显著差异(P=0.149)。土壤中ZnO-NPs对FDAH活性的抑制与ZnO-NPs浓度有良好的正相关关系,但随着暴露时间的延长,ZnO-NPs对FDAH活性的抑制减弱。
ZnO-NPs are one of the most common engineering nanoparticles at present. They are widely used in various products and have a potential impact on the ecological environment. In order to elucidate the effect of ZnO-NPs on soil microbial enzyme activity and to explore its mechanism of action and dose-effect relationship, the micro-aerobic culture system and the soil culture system were established respectively through micro-cosmic experiments. The effects of different concentrations of ZnO-NPs Fluorescein diacetate hydrolase (FDAH) activity of microorganisms was measured under exposure conditions and the activity of dehydrogenase (DH) was also measured in the pure culture system. The results showed that compared with the control without ZnO-NPs, the concentration of ZnO-NPs in the culture medium was 1, 5 and 10 mg · L-1, respectively, which significantly inhibited the activity of FDAH and DH of Microbacterium. The inhibition rate Respectively, 22.5%, 61.2%, 62.3% and 27.8%, 44.8% and 44.8% respectively. ZnO-NPs attached to the Microbacterium membrane, and some enter the bacteria, the bacteria caused oxidative damage. When the concentration of ZnO-NPs in soil was 5 mg · g-1 and 10 mg · g-1, the activity of FDAH was significantly lower than that of the control soil without ZnO-NPs (P = 0.007 and P = 0.008). When the concentration of ZnO-NPs in soil was 1 mg · g-1, the activity of FDAH was not significantly different from the control (P = 0.149). The inhibitory effect of ZnO-NPs in soil on the activity of FDAH was positively correlated with the concentration of ZnO-NPs. However, the inhibition of FDAH activity was weakened with the increase of exposure time.