纳米氧化锌对凋落物降解微生物群落结构和代谢功能的影响

随着纳米技术的迅速发展,纳米氧化锌广泛应用于抗菌涂料、电子装置、个人护理品等产品中,其生态毒理机制已成为生态学的研究热点。为了探究水生丝状真菌对纳米氧化锌的响应及适应机制,本文选用3种不同粒径的纳米氧化锌30 nm、90 nm和200 nm作为影响因子,通过室内模拟钻天杨Populus nigra L.凋落叶降解过程,研究纳米氧化锌的慢性暴露对水生丝状真菌生物量及代谢功能的影响效应,其中包括真菌的生孢率、群落多样性、脱氢酶活性、胞外降解酶活性、体系pH值、凋落叶降解速率以及碳氮含量,结果表明,粒径较小的纳米氧化锌(如30和90 nm)对水生丝状真菌活性及细菌代谢功能的抑制作用更强,且抑制作用达到显著水平所需的时间越短。46 d的慢性暴露显著影响了水生丝状真菌的生孢率与群落组成,其中Alatospora的生孢率与凋落叶降解速率呈显著负相关,表明该菌是纳米氧化锌的敏感菌,而Anguillospora和Flabellospora在纳米氧化锌的介入环境中产出较多的分生孢子,表明其为纳米氧化锌的耐受菌。另外,纳米氧化锌的长期暴露使水生丝状真菌对有机氮的降解功能具有促进作用,而对有机碳的代谢功能没有明显影响。总之,水生丝状真菌对纳米氧化锌的响应导致了凋落叶降解速率及碳氮分解效率在各处理间呈现显著差异。综上所述,本研究为纳米氧化锌对生态过程的毒理机制提供了必要的理论基础。

Impacts of Nano-scale ZnO on Microbial Community Composition and Degrading Activities Associated with Leaf Litter Decomposition

With the development of nanotechnology, nanomaterials have been widely used in the anti-bacterial coating, electronic device, personal care products, and so on. The ecotoxicity of nanomaterials has already become one of the research hotspots. To investigate the response and adaptation mechanism of aquatic hyphomycetes to nano-ZnO, indoor experiments were carried out to simulate the process of litter decomposition of Populus nigra L. leaf with different size nano-ZnO (30, 90, and 200 nm) as influence factors. The biomass and metabolic function of aquatic hyphomycetes under the chronic exposure of nano-ZnO were studied, including sporulaiton rate and community composition of aquatic hyphomycetes, dehydrogenase and extracellular enzyme activity, pH value, litter decomposition rate and carbon and nitrogen content. After 46 days of chronic exposure, results found that nano-ZnO exhibited significant effects on the sporulation rate and community composition of aquatic hyphomycetes. Alatospora sporulation rate and litter decomposition rate showed a significant negative relationship, indicating that the fungus might be sensertive genus to nano-ZnO. However, Anguillospora and Flabellospora showed a higher sporulation rate when exposed to nano-ZnO. In addition, chronic exposure of nano-ZnO promoted the fungal metabolic activity of organic nitrogen, but had no impact on organic carbon decomposition. Therefore, the response of aquatic hyphomycetes to nano-ZnO caused a significant difference on decomposition rate, organic carbon and nitrogen of leaf litter among different treatments. In conclusion, this study is expected to provide the essential fundament on the research of nano-ZnO toxicity on the ecological process.