Guo Mengran, Yang Genji, Meng Xiangwei, Zhang Tuoshi, Li Chunyan, Bai Shunwen, Zhao Xinyue
College of Resource and Environment, Northeast Agricultural University, Harbin 150030, China.
School of Environment, State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China.
Environ Int. 2023 Sep;179:108144. doi: 10.1016/j.envint.2023.108144. Epub 2023 Aug 12.
Rhizosphere is a crucial area in comprehending the interaction between plants and microorganisms in constructed wetlands (CWs). However, influence of photoperiod, a key factor that regulates photosynthesis and rhizosphere microbial activity, remains largely unknown. This study investigated the effect of photoperiod (9, 12, 15 h/day) on pollutant removal and underlying mechanisms. Results showed that 15-hour photoperiod treatment exhibited the highest removal efficiencies for COD (87.26%), TN (63.32%), and NO-N (97.79%). This treatment enhanced photosynthetic pigmentation and root activity, which increased transport of oxygen and soluble organic carbon to rhizosphere, thus promoting microbial nitrification and denitrification. Microbial community analysis revealed a more stable co-occurrence network due to increased complexity and aggregation in the 15-hour photoperiod treatment. Phaselicystis was identified as a key connector, which was responsible for transferring necessary carbon sources, ATP, and electron donors that supported and optimized nitrogen metabolism in the CWs. Structural equation model analysis emphasized the importance of plant-microbe interactions in pollutant removal through increased substance, information, and energy exchange. These findings offer valuable insights for CWs design and operation in various latitudes and rural areas for small-scale decentralized systems.
根际是理解人工湿地中植物与微生物相互作用的关键区域。然而，光周期作为调节光合作用和根际微生物活性的关键因素，其影响在很大程度上仍不为人知。本研究调查了光周期（9、12、15小时/天）对污染物去除的影响及其潜在机制。结果表明，15小时光周期处理对化学需氧量（87.26%）、总氮（63.32%）和硝态氮（97.79%）的去除效率最高。该处理增强了光合色素沉着和根系活性，增加了氧气和可溶性有机碳向根际的运输，从而促进了微生物的硝化和反硝化作用。微生物群落分析表明，15小时光周期处理由于复杂性和聚集性增加，共现网络更加稳定。Phaselicystis被确定为关键连接者，负责转移支持和优化人工湿地中氮代谢所需的碳源、三磷酸腺苷和电子供体。结构方程模型分析强调了植物-微生物相互作用通过增加物质、信息和能量交换在污染物去除中的重要性。这些发现为不同纬度和农村地区的小型分散系统人工湿地的设计和运行提供了有价值的见解。
