Abstract It investigated the nitrogen removal performance and the abundances of nitrogen functional genes in the rhizosphere and non-rhizosphere when vertical flow constructed wetland (VFCW) was used to treat brackish eutrophic water. The results demonstrated that both total nitrogen (TN) and ammonia nitrogen (NH4-N) removal efficiencies decreased with the salinity increasing from 0.05% to 1.0%. However, the removal efficiency of nitrate nitrogen (NO3-N) remained more than 93%. It was found by quantitative real-time polymerase chain reaction (qPCR) that abundances of amoA, nosZ, napA, nirK and nirS were greater in the rhizosphere than in the non-rhizosphere at the salinities of 0.05%, 0.5% and 1.0%. As the salinity increased, the abundance of amoA reduced. It indicated that the salinity inhibited the growth of ammonia oxidizing bacteria (AOB) and further hindered the nitrification, which resulted in the deterioration of TN removal performance. The abundances of nosZ, napA, nirK and nirS in the rhizosphere and non-rhizosphere were the highest at 1.0% salinity. The denitrifying bacteria might adapt to the salinity stress, which guaranteed high NO3-N removal efficiency.

中文翻译：

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对盐度响应的垂直流人工湿地根际和非根际脱氮及相关功能基因丰度

摘要 研究了垂直流人工湿地（VFCW）处理微咸水富营养化水体时的脱氮性能和根际和非根际氮功能基因的丰度。结果表明，随着盐度从 0.05% 增加到 1.0%，总氮 (TN) 和氨氮 (NH4-N) 的去除效率均降低。然而，硝态氮（NO3-N）的去除效率保持在93%以上。通过定量实时聚合酶链反应 (qPCR) 发现，在 0.05%、0.5% 和 1.0% 的盐度下，根际 amoA、nosZ、napA、nirK 和 nirS 的丰度高于非根际。随着盐度的增加，amoA的丰度减少。说明盐度抑制了氨氧化细菌（AOB）的生长，进一步阻碍了硝化作用，导致TN去除性能下降。nosZ、napA、nirK和nirS在根际和非根际的丰度最高，盐度为1.0%。反硝化细菌可能适应盐度胁迫，保证了较高的 NO3-N 去除效率。