冬季苦草与伊乐藻对贡湖水源地水质净化效果研究

2009年11月5日至25日在苏州太湖贡湖水源地入湖河道东泾河内设置了10个大型路基围隔，栽植较耐寒沉水植物苦草（Vallisneria spiralis）和伊乐藻（Elodea canadensis），研究了其在冬季低温条件下的净水效果。结果表明:（1）栽种沉水植物的围隔内氨氮、硝酸盐氮和总氮浓度均显著低于实验前（P<0.01），其中苦草实验组氨氮、硝酸盐氮和总氮浓度分别为实验前的78.76%、70.20%和 83.42%，伊乐藻实验组分别为实验前的81.85%、72.30%、75.55%，苦草+伊乐藻实验组分别为实验前的88.80%、78.80%、86.21%，而空白对照组与围隔外水质氮素浓度变化幅度较小，总氮浓度分别降低37.12%和15.87%；（2）苦草+伊乐藻实验组对总磷和COD_Mn的去除效率显著高于其他围隔（P<0.01），分别为86.97%和76.16%；（3）经驯化后的苦草和伊乐藻在冬季有较好的净化水质效果且净化效果为苦草+伊乐藻>苦草>伊乐藻，为冬季湖泊生态修复中沉水植被的恢复，种类的选取及合理配置提供了理论依据。

Study of the depuration effect of Vallisneria spiralis and Elodea Canadensis in water sources area of Gong Hu in winter

This paper studied the depuration effect of two kinds of submerged macrophytes Vallisneria spiralis and Elodea Canadensis in winter,after cold acclimation in laboratory.From 5 to 25 November 2009,ten large embankment enclosures were set up in Dong Jing River of the water source area in Gong Hu,Suzhou Vallisneria spiralis and Elodea Canadensis were planted in the enclosures.Experiments were made in 4 groups: Vallisneria spiralis,Elodea Canadensis,Vallisneria spiralis + Elodea Canadensis and control group.Each treatment had three replicates.Sampled once every five days,to test the water quality inside of the enclosure and the outside enclosure.The results showed that:(1) In the enclosures grown submerged macrophytes: concentrations of NH4-N,NO3-N,TN,were significantly lower than those before the experiment(P<0.01),and the concentrations in Vallisneria spiralis control,Elodea Canadensis control,Vallisneria spiralis + Elodea Canadensis control are reduced to 78.76%,70.20%,83.42%,81.85%,72.30%,75.55%,88,80%,78.80%,86.21%,respectively,while the control group and the water outside the enclosures have a lesser extent nitrogen concentrations,in which TN concentrations decreased 37.12% and 15.87%;(2)The control of Vallisneria spiralis + Elodea Canadensis have high reduction rate in decreasing the TP and CODMn,which were 86.97% and 76.16%,significantly higher than other controls(P<0.05).(3) The effect of purifying water of Vallisneria spiralis and Elodea Canadensis is better in winter,and the purifying effect: Vallisneria spiralis + Elodea Canadensis>Vallisneria spiralis >Elodea Canadensis.This paper provides a theoretical basis for the recovery of submerged plants of lake ecological restoration,species selection and reasonable allocation.