Zhao Biying, Xing Peng, Wu Qinglong L
State Key Laboratory of Lake Science and Environment, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China.
University of Chinese Academy of Sciences, Beijing 100039, China.
FEMS Microbiol Ecol. 2017 Oct 1;93(10). doi: 10.1093/femsec/fix108.
Knowledge of aquatic microbes involved in macrophyte leaf litter decomposition is still scarce in freshwater lakes. In situ experiments (150 days) were conducted to study the decomposition processes of macrophyte leaf litters: Zizania latifolia (Zl), Hydrilla verticillata (Hv) and Nymphoides peltata (Np). The decomposition of Np leaf litter was fastest, whereas Zl was slowest. The alpha diversity of both bacterial and fungal communities significantly increased, and their community structures showed significant variations over time. For bacteria, the relative abundance of Gammaproteobacteria decreased, whereas that of Firmicutes, Betaproteobacteria, Deltaproteobacteria and Alphaproteobacteria increased. The dominant fungal phylum Cryptomycota increased significantly in all of the three macrophytes. Both bacteria and fungi were significantly correlated with the dynamics of total phosphorous in the water and the carbon content of the leaf litters. The dynamics of nitrogen content, phosphorous content and N/P ratio of the leaf litters have more influences on fungal communities than on bacteria. In addition, cellulase and xylanase activities were significantly correlated with bacterial and fungal communities, respectively, thereby reflecting the niches differentiation and cooperation between bacteria and fungi on litter decomposition. This work contributes to the understanding of microbially involved carbon and nutrient cycling in macrophyte-dominated freshwater ecosystems.
在淡水湖泊中，关于参与大型植物落叶分解的水生微生物的知识仍然匮乏。进行了原位实验（150天）来研究大型植物落叶的分解过程：茭白（Zl）、黑藻（Hv）和荇菜（Np）。荇菜落叶的分解最快，而茭白最慢。细菌和真菌群落的α多样性均显著增加，且其群落结构随时间呈现出显著变化。对于细菌而言，γ-变形菌门的相对丰度下降，而厚壁菌门、β-变形菌门、δ-变形菌门和α-变形菌门的相对丰度增加。在所有三种大型植物中，占主导地位的真菌门隐真菌门均显著增加。细菌和真菌均与水中总磷的动态变化以及落叶的碳含量显著相关。落叶的氮含量、磷含量和N/P比的动态变化对真菌群落的影响比对细菌的影响更大。此外，纤维素酶和木聚糖酶的活性分别与细菌和真菌群落显著相关，从而反映了细菌和真菌在落叶分解过程中的生态位分化与合作。这项工作有助于理解以大型植物为主的淡水生态系统中微生物参与的碳和养分循环。
