【作者】 胡智勇；

【导师】 陆开宏；

【作者基本信息】 宁波大学 ， 渔业资源， 2009， 硕士

【摘要】 随着经济的发展和人民生活水平的提高,我国的水资源越来越紧张,水污染问题也越来越严重,其中因氮磷过剩引发的水体富营养化是最为普遍的水污染问题之一,也是国内外水环境领域的重要难题。近年来,随着对污水净化植物的研究逐渐深入,植物修复作为改善水质的一种高效低耗的方法日益受到重视,已逐渐成为环境领域的研究热点之一。本文以两种常见水生净化植物为研究对象,主要从水生植物氮吸收生理机制和根际微生物数量与植物间的关系等两个方面开展研究,以期为构建植物、微生物耦合降解系统,强化水生植物的净水功能提供理论依据。本研究选择宁波市卧彩江、日湖两个不同营养类型水体,通过跟踪调查两个水体内粉绿狐尾藻（Myriophyllum aquaticum）、喜旱莲子草（Alternanthera philoxeroides）两种水生植物根际微生物的数量动态,并结合主要水化学指标的监测,研究不同富营养类型水体植物根际微生物的群落特征及其变化;通过高浓度氮、有机物吸收实验,研究粉绿狐尾藻、凤眼莲（Eichhornia crassipes）在抑菌和非抑菌两种处理中对N（NO₃^--N、NH₄⁺-N）、COD的去除效果,并通过跟踪监测植物根际细菌、放线菌及真菌的数量动态,探讨微生物数量与污染物去除间的相关性,评价水生植物及根际微生物在不同富营养水平下的协同去污能力。主要结果如下:1采用改进常规耗竭法,研究了粉绿狐尾藻、凤眼莲在抑菌和非抑菌两种处理中对NO₃^--N、NH₄⁺-N吸收的动力学特征。结果表明:两种植物对NO₃^--N、NH₄⁺-N的最大吸收速率（Imax）和亲和力（1/ Km）有显著差异,凤眼莲对NO₃^--N、NH₄⁺-N有较大的吸收速率,说明凤眼莲更适宜用于污染水体养分的吸收;在抑菌条件下,狐尾藻对NO₃^--N、NH₄⁺-N的最大吸收速率增加15.34%、36.50%,Km分别减小21.54%、增加34.74%;凤眼莲对NH₄⁺-N最大吸收速率增加86.46%,而对NO₃^--N最大吸收速率减小47.37%;两种植物对NH₄⁺-N的亲和力减小,对NO₃^--N的亲和力增加,表明微生物可以通过改变植物根际环境影响了植物对NO₃^--N、NH₄⁺-N的吸收速率和亲和力。2在宁波市内河选取两个不同营养类型水体-日湖、卧彩江,于2008年8月-11月,利用微生物快速鉴定（MIDI Sherlock MIS）系统和其他传统方法,跟踪监测了两个水体内两种常见水生净化植物粉绿狐尾藻、喜旱莲子草根际微生物的种类和数量变化,分析了水体主要理化指标、水体微生物、植物根际微生物之间的相关关系。结果表明:水生植物根际效应显著;植物种类和水体富营养化程度均对植物根际微生物影响显著,日湖中,狐尾藻根际微生物数量要显著高于喜旱莲子草,在卧彩江中,两种植物根际细菌数量无显著差异,放线菌、真菌数量差异显著;植物根际微生物数量与环境因子间具有一定的相关性,日湖中,TN与植物根际微生物数量存在正相关,卧彩江中TN与植物根际微生物数量相关性呈负相关;两个水体中,水中微生物数量与植物根际微生物数量均存在正相关;TP、COD与植物根际微生物数量均存在负相关;水温、Chla与植物根际微生物数量相关性不显著。植物根际微生物群落结构存在季节变化,根际微生物多样性受到水体富营养化程度、气候、植物种类等多重因素的影响,夏季,日湖、卧彩江中粉绿狐尾藻根际微生物多样性指数分别为1.52、1.10,秋季则分别为1.01、2.17;喜旱莲子草根际微生物多样性指数在日湖、卧彩江中夏季为1.43、1.48,秋季为1.07、1.66。植物根际优势菌种以假单胞菌（Pseudomonas）、微球菌（Micrococcus）、黄杆菌（Chryseobacterium）、不动杆菌（Acinetobacter）等主要的有机物降解微生物为主,环境因素的多变和植物根系的不同也导致了葡萄球菌（Staphylococcus）,食酸菌（Acidovorax）、节杆菌（Arthrobacter）等特有菌种出现。3以凤眼莲为研究对象,在相同光照和温度条件下,研究了不同N、COD水平及抑菌和常规两种处理对硝氮、氨氮、有机物去除效果的影响,并分析了根际细菌、放线菌和真菌的数量动态,探讨了凤眼莲及其根际微生物对污染物的协同去污效果。结果表明:凤眼莲对NH₄⁺-N的去除效率要低于对NO₃^--N的去除效率,凤眼莲对NO₃^--N的去除没有受到抑菌处理的显著影响,而抑菌处理对凤眼莲去除NH₄⁺-N有显著影响,说明凤眼莲根际微生物在NH₄⁺-N的去除过程中发挥了重要作用;抑菌处理能显著降低凤眼莲对COD的去除效果,在COD浓度为60mg/L、120mg/L尤为显著;在中、低N环境条件下,微生物数量与NH₄⁺-N去除速率有显著正相关,而与NO₃^--N去除速率呈负相关,说明在中、低N环境中根际微生物活动对NH₄⁺-N的去除有一定的影响;微生物活动对COD的去除起重要作用,并且在不同COD浓度条件下,发挥主要作用的微生物类群有所差异。4以粉绿狐尾藻为研究对象,在相同光照和温度条件下,研究了不同N、COD水平及抑菌和常规两种处理对NO₃^--N、NH₄⁺-N、COD去除效果的影响,并分析了植物根际细菌、放线菌和真菌的数量动态,探讨了粉绿狐尾藻及其根际微生物对污染物的协同去污效果。结果表明:在中、低N浓度下,抑菌和非抑菌组狐尾藻对NO₃^--N、NH₄⁺-N的去除没有显著差异;高N浓度下,抑菌和非抑菌狐尾藻对NO₃^--N的去除率分别为31.30%、37.57%,有显著差异,对NH₄⁺-N的去除率仍无显著差异;在COD浓度为60mg/L时,抑菌和非抑菌组无显著差异,水溶液COD浓度为120mg/L、180mg/L时,非抑菌组狐尾藻对有机物的降解速率要显著高于抑菌处理组;无论是抑菌组还是非抑菌组,植物根际的微生物数量与NO₃^--N去除速率无显著相关,抑菌组中,植物根际细菌数量与NH₄⁺-N、COD去除速率显著相关,说明在狐尾藻根际细菌参与了NH₄⁺-N、COD的去除,而NO₃^--N的去除与微生物活动无密切联系。更多还原

【Abstract】 Due to rapid industrial development and growth of population, water resources are becoming scarce, and water contamination is appearing to be a serious problem, and eutrophication has been a serious phenomenon, become the most difficulty in environmental remediation for water pollution. With the increase of attention to the environmental ecology, using the phytoremediation methods to rehabilitate polluted groundwater （including river, lake and reservoirs） has become more and more popular. Our research focused on the use of plants such as macrophytes that can absorb nitrogen, to assess their ability to purify nitrogen polluted water, and quantitative dynamics and synergistic pollutant removal action of microorganisms in the rhizosphere macrophytes. The main purpose was to understand abilities of different macrophytes species rehabilitate eutrophicated water.The research assessed the function of rhizosphere microorganisms by experiment of nitrogen uptake kinetics of macrophytes. We studied the community structure and quantitative dynamics of two plants in Rihu Laker and Wocaijiang River in Ningbo in different seasons. By the field investigation, we accumulated the basic data community structure and synergistic pollutant removal action of microorganisms in the rhizosphere of several macrophytes. The research focused on E.crassipes and M.aquaticum to assess there ability to purify nitrogen, organic compounds polluted water, and quantitative dynamics and synergistic pollutant removal action of microorganisms in the rhizosphere of macrophytes under nutrient solution of antimicrobial treatment and normal treatment. Our main research work and conclusions follows:1. The nutrient uptake kinetics of M.aquaticum and E. crassipes were investigated using the modified depletion method under nutrient solution of antimicrobial treatment and normal treatment. The maximum uptake rate （Imax） and Michaelis–Menten constant （Km） were estimated by iterative curve fitting. The Imax and Km for the plants was significantly different between two plants. The Imax for NO₃^--N、NH₄⁺-N in E.crassipes is higher than that in M.aquaticum, illuminated that M.aquaticum was proper for treatment of the seriously polluted water. Imax for NO₃^--N、NH₄⁺-N in M.aquaticum increased by 15.34%、36.50% under antimicrobial treatment. Km for NO₃^--N decreased by 21.54%, and Km for NH₄⁺-N increased by 34.74%. Imax for NH₄⁺-N in E.crassipes increased 86.46%, and that for NO₃^--N decreased 47.37%. Km for NH₄⁺-N in two macrophytes both decreased, and that for NO₃^--N both increased. The results showed that rhizosphere microorganisms could effect the NO₃^--N、NH₄⁺-N in E.crassipes and M.aquaticum by change t rhizosphere factors.2. In this experiment, we measured the numbers of rhizosphere microorganisms in Myriophyllum aquaticum and Alternanthera philoxeroides in Rihu Laker and Wocaijiang River in Ningbo, and their correlation with environmental factors. The population diversity of microorganisms was studied by Sherlock Microbial Identification System （Sherlock MIS）. The results indicate: Plants rhizosphere effects was significant. In Rihu laker, the microbial number in the rhizosphere of Myriophyllum aquaticum was significantly higher than that in the rhizosphere of Alternanthera philoxeroides. There was no significant difference between the numbers of bacteria in the rhizosphere of two plants. The numbers of rhizosphere actinomyces and fungi were significant different between plants. There correlation between the numbers of rhizosphere microorganisms and environmental factors. The correlation restricted by the environmental factors. There was a positive correlation between the numbers of rhizosphere microbes and TN in Rihu Laker. The numbers of rhizosphere microbes and TN had no correlation in c. The numbers of rhizosphere microbes had positive correlation with microorganisms in water, and had negative correlation with TP and COD, and had no correlation with water tempterature and Chla in both Rihu Laker and Wocaijiang River. Community Structure of rhizosphere microbes of macrophytes changed with season. Diversity of rhizosphere microorganisms restricted by eutrophication degree, climate and species of macrophyte and so on. In summer, the diversity index of rhizosphere microbes in M. aquaticum was 1.52 and 1.10 in Rihu Laker and Wocaijiang River. And the index changed to be 1.01 and 2.17 in autumn. The diversity index in A. philoxeroides was 1.43 and 1.48 in summer, and changed to be 1.06 and 1.66 in autumn. The predominant microbes in the rhizosphere of macrophytes Pseudomonas, Micrococcus, Chryseobacterium, Acinetobacter. There were some special microorganisms（e.g., Staphylococcus, Acidovora, Arthrobacter） were found because of the difference of environmental factors.3. The research focused on E.crassipes to assess it’s ability to purify nitrogen, organic compounds polluted water, and quantitative dynamics and synergistic pollutant removal action of microorganisms in the rhizosphere of E.crassipes under nutrient solution of antimicrobial treatment and normal treatment. The results showed that, at the same condition, the removal efficiency of NH₄⁺-N is lower that of NO₃^--N. Antimicrobial treatment had no significant effect on the removal of NO₃^--N. A significant effect was found on the removal of NH₄⁺-N between antimicrobial treatment and normal treatment. It showed that rhizosphere microbes played an important role in removal of NH₄⁺-N. The removal efficiency of COD under normal treatment was significant higher than that under antimicrobial treatment, especially when the concentration of COD in the initial solution was 60mg/L, 120mg/L. At low concentration , there was a positive correlation between variation rate of rhizosphere microorganisms and removal efficiency of NH₄⁺-N, and a negative correlation was found between variation rate of rhizosphere microorganisms and removal efficiency of NO₃^--N. The results showed that rhizosphere microorganisms was important for the removal of NH₄⁺-N. It’s also found that rhizosphere microorganisms played on important role in the removal of organic compounds. Differernt kinds of microorganisms played a role in the removal of organic compounds at different concentration of COD.4. The research focused on M.aquaticum o assess it’s ability to purify nitrogen, organic compounds polluted water, and quantitative dynamics and synergistic pollutant removal action of microorganisms in the rhizosphere of M.aquaticum under nutrient solution of antimicrobial treatment and normal treatment. The results showed that, the removal efficiency of NO₃^--N had no significant different between antimicrobial treatment and normal treatment at low concentration of nitrogen. The same result was found in the removal efficiency of NH₄⁺-N. The removal efficiency of NO₃^--N under antimicrobial treatment and normal treatment was respectively 31.30%, 37.57% at high concentration of nitrogen. It was significant different between two treatment. There was no significant difference in the removal efficiency of NH₄⁺-N between two treatment at high concentration of nitrogen. When the concentration of COD in the initial solution was 120mg/L, 180mg/L, the removal efficiency of organic compounds under normal treatment was significant higher than that under antimicrobial treatment. No significant difference was found when the concentration of COD in the initial solution was 60mg/L. A negative correlation was found between variation rate of rhizosphere microorganisms and removal efficiency of NO₃^--N. There were significant correlation between variation rate of bacteria and removal efficiency of COD and NH₄⁺-N under antimicrobial treatment. It showed that the bacteria in the rhizosphere of M.aquaticum played a role in the removal of COD and NH₄⁺-N. There was no close connection between the removal of NO₃^--N and microbial activity in the rhizosphere M.aquaticum.更多还原