多年生漂浮植物对富营养化水体的响应及净化效果研究

Response and Purification of Perennial Floating Plants in Eutrophic Waterbody

研究了喜旱莲子草、穗状狐尾藻、黄花水龙3种植物在富营养化水体中的生长响应及对水体的净化效果。结果表明,试验确定了穗状狐尾藻最佳生长阈值：N 0.05-0.1 mg/L,P 0.01-0.02 mg/L;黄花水龙：N 0.1-0.2 mg/L,P 0.005-0.01 mg/L。试验结果进一步确定了穗状狐尾藻、黄花水龙阈值氮磷比例范围分别为2∶1-10∶1,10∶1-20∶1。在试验第35 d时,穗状狐尾藻对总氮、总磷和叶绿素a去除率分别达到了90.5%,88.0%,90.0%,效果最佳;黄花水龙对NO3-N、NH4-N去除效果最好,分别为85.0%,43.5%。对水体中氮的去除主要是微生物和植物吸收共同作用完成,试验进行到35 d时,所用供试植物体内最大积累量占水体初始总氮量的10.36%,仅占水体氮去除的一小部分;通过有植物处理和无植物处理（即对照）对水体中营养盐去除效果的比较得出：3种供试植物对水体氮代谢微生物有正激发效应,而对磷代谢微生物均有负激发效应。

The response to eutrophic water,purification effectiveness of three floating plants（Alternanthera philoxeroides,Myriophyllum spicatum,Jussiaea stipulacea） were studied.The thresholds of N,P levels and N/P ratios for the plants to grow were found.The thresholds of N,P levels and N/P ratio for Myriophyllum spicatum,were N 0.05-0.1 mg/L,P 0.01-0.02 mg/L,and 2∶1-10∶1,respectively.While those for Jussiaea stipulacea Ohwi were N 0.1-0.2 mg/L,P 0.005-0.01 mg/L,and N/P ratio 10∶1-20∶1 respectively.The results showed that Myriophyllum spicatum had a better removal of TN and TP from the eutrophic water,with the removal rates being：TN：90.5%,TP：88.0%,Chl-a：90.0%.Whereas Jussiaea stipulacea had better removal of nitrate and ammonia from the water,with the removal rate being NO3-N：85.0% and NH4-N：43.5%.The removal of nitrogen were ascribed to interaction of microorganism with plant,as the highest plant accumulation of nitrogen accounted for only 10.36% of the total concentration of the original eutrophic water body.These three plants had positive effect on the plant-enhanced microbial removal of nitrogen,because the plants had stimulative effect on nitrogen metabolic microorganism.However,the plants had negative effect on phosphorus metabolic microorganisms.