不同植物搭建人工湿地的根系分泌物组成及其对养殖尾水的处理效果

Composition of different plant root exudates in vertically constructed wetlands and their treating effects on aquaculture wastewater

种植植物的人工湿地可以通过根系分泌物及根际泌氧显著提高其对养殖尾水处理的性能。而不同植物种类和环境会影响根系分泌物释放情况,本实验通过搭建三组垂直流人工湿地处理养殖尾水,分别为无植物(NP)、风车草组(FCC)、鸢尾组(YW)。检测其根系分泌情况并分析其与污染物去除率间的相关性。样品中检测到并且具有CAS号(CAS Registry Number)的化合物共有84种,其中鸢尾有82种,风车草有24种。鸢尾组检测出的柠檬酸的相对浓度为(62.3±9.65)μg/mL,为检测出的相对浓度最高的根系分泌物,且其与NO_(3)^(-)-N和TN的去除率呈显著的正相关。种植植物组对NO_(2)^(-)-N的去除效果更稳定且显著高于NP组;种植植物组对NO_(3)^(-)-N的去除率显著高于NP组,YW组显著高于FCC组,其中L-苯丙氨酸、柠檬酸等根系分泌物与NO_(3)^(-)-N的去除率呈正相关;对NH_(4)^(+)-N和TN的去除率,种植植物组均显著高于NP组,其中FCC组对NH_(4)^(+)-N的去除率高于YW组,分泌物L-缬氨酸和胆碱与NH_(4)^(+)-N的去除率呈正相关。本研究利用高效液相色谱串联质谱技术较为全面地检测了风车草与鸢尾的根系分泌物组成情况,为应用根系分泌物强化人工湿地提供了理论参考。

constructed wetlands with plants can significantly improve the removal efficiency of pollutants because of root exudates and oxygen excretion.Different plant species and environments will affect the release of root exudates.Thus three groups of vertical flow constructed wetlands[no plant group(NP),Iris tectorum Maxim group(YW),and Cyperus involucratus Rottboll group(FCC)]were constructed to treat simulated aquaculture wastewater.The root exudates released by plants was detected and its correlation with the removal rate of pollutants was analyzed.A total of 84 compounds with CAS numbers were chosen for the following analysis.There were 82 species for YW and 24 species for FCC.Among all root exudates,the highest concentration of citric acid was detected in the YW group,and its relative concentration was 62.30±9.65μg/mL,which was significantly positively correlated with the removal rates of NO_(3)^(-)-N and TN.The removal efficiency of NO_(2)^(-)-N in groups with plants was significantly higher than that in the NP and more stable.The removal efficiency of NO_(3)^(-)-N in groups with plants was significantly higher than that in the NP,and that in the YW was significantly higher than that in FCC.L-phenylalanine and citric acid were positively correlated with NO_(3)^(-)-N removal efficiency.The removal efficiency of NH_(4)^(+)-N and TN in groups with plants was significantly higher than that in the NP,and the removal efficiency of NH_(4)^(+)-N in FCC was higher than that in the YW.L-valine and choline were positively correlated with the removal of NH_(4)^(+)-N.In this study,the composition and characteristics of root exudates in the constructed wetlands treating simulated aquaculture wastewater were comprehensively detected for the first time by high-performance liquid chromatography tandem mass spectrometry,which provided a theoretical reference for the application of root exudates to strengthen the treating effect of constructed wetlands.