纳米铜(CuNPs)对土壤微生物群落PLFA特征及酶活性的影响

Effect of copper nanoparticles(CuNPs)on soil microbial community PLFA characteristics and enzyme activity in soil

纳米铜(Copper nanparticles,CuNPs)因其独特的性质被广泛使用,因此研究其释放到环境中所带来的不利影响十分重要。通过室内暗培养试验,探究纳米铜对土壤微生物群落结构多样性及酶活性的影响。土壤微生物群落组成和结构测定采用磷脂脂肪酸生物标记法,土壤酶活性测定采用分光光度法。结果表明,添加CuNPs(5 mg/kg、10 mg/kg、20 mg/kg、50 mg/kg和100 mg/kg)后土壤总磷脂脂肪酸(Phospholipid Fatty Acid,PLFA)含量与对照相比降低了19.1%~32.7%,纳米铜处理对革兰氏阳性菌PLFA、革兰氏阴性菌PLFA、细菌PLFA、放线菌PLFA、真菌PLFA、丛枝菌根真菌PLFA、厌氧菌PLFA、真核生物PLFA的含量造成不同程度上抑制。除10 mg/kg纳米铜处理下革兰氏阳性菌与革兰氏阴性菌(G+/G-)的值及50 mg/kg纳米铜处理下真菌/细菌(F/B)的值升高外,其他处理下G+/G-和F/B的比值均呈下降趋势。土壤微生物聚类分析(Cluster analysis)及主成分分析(Principal component analysis)结果显示不同质量比纳米铜处理下微生物群落结构差异明显。土壤微生物生态学指数结果为Simpson指数降低了2.4%~4.9%、Shannon指数降低了2.2%~6.1%、Pielou指数降低了3.4%~6.9%,表明添加纳米铜对土壤中微生物群落多样性产生了负面影响。添加纳米铜抑制土壤脲酶、脱氢酶、碱性磷酸酶和过氧化氢酶活性,与对照相比,分别降低了29.4%~82.9%、8.4%~62.1%、35.8%~76.2%和15.7%~47.1%。综上分析,纳米铜进入土壤后会对土壤酶活性和微生物结构多样性产生一定的抑制作用。

Copper nanoparticles are widely used due to their unique properties,so it is very important to study the adverse effects brought about by their release into the environment.The effects of copper nanoparticles(CuNPs)on soil microbial community diversity and enzyme activity were studied by inhouse dark culture experiments.The soil microbial content was determined by the phospholipid fatty acid biomarker method,and the soil enzyme activity was determined by the spectrophotometer method.The results show that the amount of total phospholipid fatty acid(PLFA)under the addition of 5 mg/kg,10 mg/kg,20 mg/kg,50 mg/kg,and 100 mg/kg CuNPs decreases by 19.1%-32.7%in contrast to the control groups.The treatments with CuNPs can lead to inhibitory effects on the number of grampositive bacteria PLFA,gram-negative bacteria PLFA,bacteria PLFA,fungi PLFA,actinomycete PLFA,arbuscular mycorrhizal fungi PLFA,eukaryotic PLFA,and anaerobic bacteria PLFAs.Except for the increase in the value of Gram-positive bacteria and Gram-negative bacteria(G+/G-)under 10 mg/kg CuNPs treatment and the value of fungi/bacteria(F/B)under 50 mg/kg CuNPs treatment,the ratio of G+/G-and F/B show a downward trend under other treatments.The results of soil microbial cluster analysis and principal component analysis show that the microbial community structure is significantly different under different dosages of CuNPs.The results of the soil microbial ecology index show that the Simpson index decreases by 2.4%-4.9%,the Shannon index decreases by 2.2%-6.1%,and the Pielou index decreases by 3.4%-6.9%,indicating that the addition of CuNPs has a negative effect on the diversity of the microbial community in the soil.By applying of CuNPs,the activities of urease,dehydrogenase,alkaline phosphatase,and catalase are reduced by 29.4%-82.9%,8.4%-62.1%,35.8%-76.2%,and 15.7%-47.1%,respectively.Based on the above analysis,once CuNPs enter the soil,they would have a certain inhibitory effect on soil enzyme activity and microbial structure diversity.