【作者】 罗英；

【导师】 薛建辉；

【作者基本信息】 南京林业大学 ， 生态学， 2012， 博士

【摘要】 本论文以氮吸收能力较强的水生植物水芹、石菖蒲、三白草为研究对象，探讨模拟酸雨和富营养化复合胁迫对水生植物根系活力、叶片硝酸还原酶活力、多胺的含量及根系氮吸收能力的影响，探讨酸雨和富营养化复合胁迫对水生植物根系吸收不同形态氮素的机理，为选择适宜的植物用于浅水湖泊水生植被的恢复和重建提供科学依据。主要结果如下：1、石菖蒲的根系活力值不随酸雨处理次数的增加而降低。三白草的根系活力值随酸雨次数和酸度的增加呈下降趋势。酸雨和富营养化复合胁迫对三白草根系活力的影响显著，而对石菖蒲根系活力的影响较小。2、石菖蒲和三白草叶片的硝酸还原酶活力均随着富营养化程度的提高而呈降低趋势。pH2.0酸雨处理对石菖蒲和三白草叶片硝酸还原酶活力的影响均较大。三白草叶片硝酸还原酶活力随酸雨次数增多而下降。酸雨处理次数的增多可促使石菖蒲叶片硝酸还原酶同工酶谱增加，从而提高硝酸还原酶活力。3、受酸雨胁迫时，三白草腐胺含量增加，酸雨与富营养化对三白草无交互作用影响；石菖蒲叶片腐胺含量先增加，且随酸雨次数的增加而下降。石菖蒲叶片（Spd+Spm）/Put的比值均呈现先降后升的变化趋势，变化幅度较大，并均在第四次酸雨后达到最大值。而三白草叶片（Spd+Spm）/Put的比值呈现出升降波动变化趋势，变化幅度远小于石菖蒲叶片。4、水芹根部对NH₄⁺和NO₃^-均有吸收偏好，三白草根部偏好吸收NH₄⁺，石菖蒲根部则偏好吸收NO₃^-。5、不同强度酸雨处理后水芹根对NH₄⁺的吸收明显降低；超富营养水平下酸雨处理后水芹根均外排NO₃^-。石菖蒲根部500μm处吸收NO₃^-，富营养水平的提高使石菖蒲根部对NO₃^-的吸收降低，而酸度的提高会增强石菖蒲根对NO₃^-的吸收；超富营养水平下pH3.5酸雨处理后石菖蒲在500μm和10000μm处吸收NH₄⁺。随着富营养化程度的提高，三白草根部对NH₄⁺的吸收减少；随离根尖距离的增加三白草根部对NH₄⁺的吸收增加。6、富营养化与酸雨复合胁迫对水芹、三白草和石菖蒲根区NH₄⁺和NO₃^-的离子通量均有显著的互作效应，且作用方式各异。7、石菖蒲宜在受酸雨影响的水域种植；三白草宜在酸雨和富营养化复合胁迫较严重的水域种植，尤其在NO₃^--N污染严重的水域成效明显；水芹则适宜在两者轻度污染水域种植。更多还原

【Abstract】 Three aquatic plants, Oenanthe javanica,Acorus gramineus and Saururus chinensis wereselected as experimental materials with higher N uptake abilities. Effects of acid rain andeutrophication combined stress on N uptake of acquatic plants were investigated, including rootactivity, nitrate reductase（NR） activity, polyamines contents and N uptake ability and so on. Theresults could provide a reference for restoration and reconstruction of acquatic plants in lakeecosystems and understanding of different N uptake mechanisms of acquatic plants in thecontaminated water body. Main results are described as follows:（1）The root activity of A. gramineus was not reduced with increasing frequency of acid rain.Root activity of S. chinensis was reduced with increasing frequency and intensity of acid rain.The interaction of combined stress had significant influence on root activity of A. gramineus butfewer influence on that of S. chinensis.（2）NR activity was reduced with increasing degree of eutrophication both of A. gramineusand S. chinensis. The simulated acid rain with pH1.78had great influence on NR activity both ofA. gramineus and S. chinensis. NR activity of S. chinensis was reduced with increasing frequencyof acid rain. Increasing frequency of acid rain could induce the increase of bands of NR isozymeand increase NR activity of A. gramineus. Eutrophication and acid rain had interaction on NRactivity.（3）Under acid rain stress, the Put content of S. chinensis increased. Eutrophication and acidrain combined stress had no interaction on it. On the other hand, the Put content of A. gramineusincreased firstly,then decreased with increasing frequency of acid rain.The ratio of （Spd+Spm）/Put rose firstly and then falled,with a great fluctuation. It reachedthe peak value after the fourth acid rain treatment in A. gramineus. The ratio of （Spd+Spm）/Putpresented different trend, with less degree of change in S. chinensis than that in A. gramineus.（4）The root of O. javanica could both absorb more NH₄⁺and NO₃^-, the root of S. chinensisprefer more NH₄⁺, and the root of A. gramineus prefer more NO₃^-.（5）The absorption of NH₄⁺by root of O. javanica could be definitely reduced after differentintensitied of acid rain treatments. They even exhausted NO₃^-under hyper eutrophication level.The root of A. gramineus absorbed more NO₃^-at500μm, and reduced it with increasing degree ofeutrophication, but increased with increasing intensity of acid rain. After pH3.5acid raintreatment with hyper eutrophication level, the root of A. gramineus could absorb NH₄⁺at both500μm and10000μm. The absorption of NH₄⁺by S. chinensis could be reduced with increasingeutrophication level,and increased with increasing distance from the tip of its root.（6） Eutrophication and acid rain combined stress has significant interaction and differentaction ways on the fluxes of NH₄⁺and NO₃^-by O. javanica, A.gramineus and S. chinensis. （7） A.gramineus could be planted in waterbodies with acid rain pollution. S. chinensis couldbe planted in lake wetlands with serious acid rain and eutrophication pollution. O. javanica couldbe planted more suitably in lightly polluted wetlands.更多还原