【作者】 向律成；

【导师】 杨肖娥；

【作者基本信息】 浙江大学 ， 植物营养学， 2010， 硕士

【摘要】 近年来,水体富营养化已成为一个世界性难题,如何治理富营养化水体成为科学界研究的热点问题。生态方法由于其无污染,成本低,正受到越来越多的科研工作者青睐。生态方法对富营养化水体中氮磷的去除效果研究主要集中在大型水生植物以及单一影响因子,但对植物的净化效率,生长特性,环境影响因子的系统研究还少见报道。本文从上述几方面系统研究了三种水生植物喜旱莲子草、穗状狐尾藻、黄花水龙等的修复效果,生长特性,影响因子,以期为各植物更科学的应用于富营养化水体的修复提供理论依据。本研究所取得的主要结论如下:1.试验确定了穗状狐尾藻氮、磷阈值范围为:N:0.05-0.1mg/L;P:0.01-0.02mg/L;黄花水龙:N:0.1-0.2mg/L;P:0.005-0.01mg/L,二者均能在贫营养自然水体中生长,穗状狐尾藻表现出对氮更强的适应性,而黄花水龙表现出对磷更强的适应性。2.实验证明在低浓度水平时,氮为黄花水龙和喜旱莲子草生长的主要限制因子,磷为穗状狐尾藻生长的主要限制因子。穗状狐尾藻在低氮磷比2:1时生物量最大;黄花水龙在中等氮磷比10:1-20:1时生物量最大;喜旱莲子草在较高氮磷比20:1-40:1时生物量最大。植物对氮、磷的积累量基本趋势与生物量相似。穗状狐尾藻和黄花水龙的大田实验的生物量增长趋势符合“S”型生长曲线,对氮、磷的积累与变化与生物量变化趋势一致。3.试验得出了试验各处理中植物吸收和微生物作用对水质净化的贡献率。不同植物对水体中氮磷净化效果贡献率不同,对氮去除贡献率方面穗状狐尾藻＞黄花水龙＞喜旱莲子草;对磷去除贡献率穗状狐尾藻＞喜旱莲子草＞黄花水龙。栽种喜旱莲子草、穗状狐尾藻、黄花水龙等植物后对除氮的微生物群落结构产生正激发效应,激发效应分别为:32.60%,35.64%,34.22%,而对除磷的微生物群落结构产生负激发效应。4.穗状狐尾藻和黄花水龙有较广的温度适宜范围和pH适应范围。20℃-30℃和中性pH范围内两者生长最好。穗状狐尾藻和黄花水龙在生物量、总氮去除率、总磷去除率方面均是30℃＞20℃＞10℃。两植物由于快速生长的能力和较广的温度适宜范围让其具备了很好的应用于生态修复的特征。5.经过野外大田实验的监测与观察,穗状狐尾藻和黄花水龙全年都有超过8个月的修复效应。特别是穗状狐尾藻,每年的良好修复时间为每年的3-12月,修复效果明显,周期长,因此,这两种植物都是具有良好修复前景的优选植物品种,值得进一步推广。更多还原

【Abstract】 Nowadays, water eutrophication has becoming a worldwide difficult problem, how to solve it is a hot point around the world. Phytoremediation is becoming a popular solution because of its non-pollution, low cost and ecologically sound. A lot has been studied ahout aquatic macrophytes and their application to phytoremediation, however, less information is available about the systematic researches on effectiveness of purification by different floating aquatic plant species with relation to their growth characteristics and environment factors. The objectives of this paper were to compare the effectiveness of purification of eutrophic water by different aquatic plant species (Alternanthera philoxeroides, Myriophyllum spicatum, Jussiaea stipulacea Ohwi) and the influencing factors. The main results are summarized as follows:1. The results showed that growth responses to low nitrogen and phosphorus concentration were different among the tested floating plant species. The lowest nitrogen and phosphorus concentrations for the plant to stop growth was N:0.05-0.1mg/L; P:0.01-0.02mg/L for Myriophyllum spicatum(M), whereas N:0.1-0.2mg/L; P: 0.005-0.01mg/L.for Jussiaea stipulacea Ohwi(J). Both floating aquatic plants can grow in relative low N and P water body. Myriophyllum spicatum has a better endurance to low N but less durable ability to low P, as compared to Jussiaea stipulacea Ohwi.2. The results indicated that Myriophyllum spicatum had a maximum biomass at water body with N/P ratio of 2:1, while Jussiaea stipulacea Ohwi had best growth at N/P ratio of 10:1-20:1, and Alternanthera philoxeroides grew best at N/P ratio of 20:1-40:1. At low levels of N and P water body, nitrogen was the limiting factor for growth of Alternanthera philoxeroides, Jussiaea stipulacea Ohwi, but phosphorus was the limiting factor for growth of Myriophyllum spicatum. The nitrogen and phosphorus accumulation by the plants showed a similar pattern as biomass with relation to N/P ratio. Field experiments showed that the biomass, nitrogen and phosphorus accumulation of Jussiaea stipulacea Ohwi and Myriophyllum spicatum corresponded well with the patterns of "S".3. Experiment show different contribution of plants and microbial in different treatment. The treatment to nitrogen removal efficiency: Myriophyllum spicatum> Jussiaea stipulacea Ohwi. > Alternanthera philoxeroides. , but to phosphorus removal efficiency is Myriophyllum spicatum> Alternanthera philoxeroides.>Jussiaea stipulacea Ohwi. Alternanthera philoxeroides, Myriophyllum spicatum, Jussiaea stipulacea Ohwi had positive effect (32.60%, 35.64%, 34.22% respectively) on the plant-enhanced microbial removal of nitrogen, because the plants had stimulative effect on nitrogen metabolic microoganism. However, the plants had negative effect on phosphorus metabolic microoganisms.4. Myriophyllum spicatum, Jussiaea stipulacea Ohwi had broad ranges of adaption to temperature and pH. They showed better growth at the temperature of 20℃-30℃and neutral pH (pH≈7). Temperature had the same effects on biomass of both plant species. The removal of total nitrogen and total phosphorus decreased with decreasing of temperature: 30℃>20℃>10℃.5. According to the observation and testing under field condition yearround, we found that Myriophyllum spicatum, Jussiaea stipulacea Ohwi had effective removal of nutrients from eutrophic water body for over 8 months per year. Myriophyllum spicatum had effective nutrient removal abilities in most time of a year, from March to December. So both plant species had a great potential for application in phytoremediation engineering of eutrophic water body.更多还原