摘要:为了研究人工湿地处理中碳/氮水平的废水时植物种类及多样性对系统甲烷释放及功能基因丰度的影响，我们构建了实验尺度的人工湿地微宇宙实验系统。选取千屈菜（Lythrum salicaria L.）和海寿花（Pontederia cordata L.）2种人工湿地常用、景观效果好的植物，在系统中配置了单种处理和两物种混种处理。结果表明：千屈菜与海寿花混种系统的甲烷释放强度（8.78 mg CH₄ m^-2 d^-1）高于两物种单种系统的平均值（6.97 mg CH₄ m^-2 d^-1）（P < 0.001），同甲烷释放一样，混种系统的mcrA基因绝对丰度（977541.6 copies/g dw soil）也高于两物种单种系统的平均值（585146.8 copies/g dw soil），但混种系统的pmoA基因绝对丰度（326956.6 copies/g dw soil）低于两物种单种系统的平均值（1043616.0 copies/g dw soil）（P < 0.001）。此外，混种系统的微生物量、植物生物量高于两物种单种系统的平均值（P < 0.01），但出水铵态氮浓度低于两物种单种系统的平均值（P < 0.05），出水总有机碳浓度和硝态氮浓度在单混种系统间无显著差异（P > 0.05）。千屈菜单种系统和海寿花单种系统间的甲烷释放强度、pmoA基因绝对丰度、微生物量、植物生物量和出水铵态氮浓度存在显著差异（P < 0.05），但mcrA基因绝对丰度、出水总有机碳和硝态氮浓度无显著差异（P > 0.05）。为了达到人工湿地的高净化效率，需要将千屈菜与海寿花混合种植，但混合种植强化甲烷释放。通过植物种类和丰富度对各指标变异的解释度（ω²）分析发现，植物种类对甲烷释放、pmoA基因绝对丰度、出水铵态氮的影响大于植物丰富度，但对mcrA基因绝对丰度的影响小于植物丰富度。



Abstract:To investigate the effects of plant species and diversity on methane emissions and functional gene abundances under middle influent C/N ratio, we developed laboratory-scale constructed wetlands. Two plants, Lythrum salicaria and Pontederia cordata, which are often used in constructed wetlands and have good landscape values, were selected to establish current planting patterns, e.g. the one-species monoculturing and two-species mix culturing systems. Results showed that methane emissions from the mix culturing systems were higher (8.78 mg CH₄ m^-2 d^-1) than the mean values of the two monoculturing systems (6.97 mg CH₄ m^-2 d^-1) (P < 0.001). Similar to methane emissions, the absolute abundance of mcrA from mixed systems was also higher (977541.6 copies/g dw soil) than the mean value of the two monoculturing systems (585146.8 copies/g dw soil). However, the absolute abundance of pmoA from the mixed systems (326956.6 copies/g dw soil) was lower than the mean values of the two monoculturing systems (1043616.0 copies/g dw soil) (P < 0.001). In addition, both microbial biomass and plant biomass in the mix culturing systems were higher (P < 0.01), but the NH₄⁺-N concentration of effluent in the mix culturing systems was lower than the mean value of the two monoculturing systems (P < 0.05), and there was no significant difference in TOC and NO₃^--N concentrations between the two systems (P > 0.05). There was a significant difference in the methane emission, absolute abundance of pmoA, microbial biomass, plant biomass, and effluent NH₄⁺-N concentration between two monoculturing systems planting with Lythrum salicaria and Pontederia cordata, but there was no significant difference in the absolute abundance of mcrA, effluent TOC and NO₃^--N concentrations between the two monoculturing systems with Lythrum salicaria and Pontederia cordata. In order to achieve the high purification efficiency of constructed wetlands, it is necessary to mix planting of Lythrum salicaria and Pontederia cordata, but mix planting enhances methane release. By using the variation (ω²), we found that although the effect of plant species on methane emissions, pmoA absolute abundance and effluent NH₄⁺-N concentration was greater than that of plant species richness, the effect of plant species on mcrA absolute abundance was smaller than the effect of plant richness.





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