水华蓝藻促使凤眼莲氮素富集能力升高的机理研究

Nitrogen reduction with Eichhornia crassipes planted in eutrophic waters has increasingly become a measure and received worldwide attention. It may exert a great influence on nitrogen reduction effect when a change occurs in nitrogen accumulation ability of E. crassipes. Findings from previous studies have confirmed that bloom-forming cyanobacteria played an outstanding role in the improvement of nitrogen accumulation ability of E. crassipes. These results have guiding significance for nitrogen removal from algae eutrophic water with E. crassipes. But, the intrinsic mechanisms on the enhanced ability of the plant are still unclear. Therefore, by virtue of the 15N tracer technique, sterile culture technique, and electron microscopy, release process and regularity of cyanobacterial nitrogen will be studied, as well as the efficiency of absorption and conversion on the nitrogen by E. crassipes. In addition, not only the impacts of bloom-forming cyanobacteria on root shape including surface area and its ultrastructure will be investigated, but the impacts on nitrogen absorption and transformation capabilities of the root such as root activity, nitrate reductase activity, and ion pump activity will all be monitored and analyzed, so as to reveal the intrinsic mechanism on the improved nitrogen accumulation ability of E. crassipes by bloom-forming cyanobacteria. This study will be carried out from multiple aspects or different angles to reveal the intrinsic mechanism on this phenomenon. The results of this study will provide practical and theoretical references for nitrogen removal by ecological engineering with E. crassipes from algae dominant eutrophic water, and it also has huge realistic and scientific significance.

采用凤眼莲削减富营养化水体氮素已日益成为广为关注的举措，凤眼莲氮素富集能力的改变将对其氮素削减效果产生重大影响。申请人经长期监测发现水华蓝藻可促使凤眼莲氮素富集能力的提高，这对采用凤眼莲移除藻华水体氮素有重要指导意义。然而，有关水华蓝藻对凤眼莲氮富集能力的影响机理还不清晰。为此，本申请拟凭借15N示踪、无菌苗培养、电镜观察等技术手段，从蓝藻氮素的释放过程与规律以及凤眼莲对蓝藻释放氮素的吸收转化效率的角度；从蓝藻对凤眼莲根系形态包括其表面积与超微结构等方面影响的角度；从蓝藻对根系氮素吸收转化能力影响的角度，如根系活力、与氮素吸收转化密切相关的硝酸还原酶和离子泵等。从多层面不同角度进行探究与分析，揭示蓝藻促使凤眼莲氮素富集能力升高的内在机理。本研究的结果将为采用凤眼莲生态工程移除藻华水体氮素提供有力的实践借签和理论参考，具有重要的现实意义和科学意义。

采用凤眼莲削减富营养化水体氮素已日益成为广为关注的举措，凤眼莲氮素富集能力的改变将对其氮素削减效果产生重大影响。前期研究发现，水华蓝藻可促使凤眼莲氮素富集能力的提高，这对采用凤眼莲移除藻华水体氮素有重要指导意义。然而，有关水华蓝藻对凤眼莲氮富集能力的影响机理还不清晰。为此，本项目凭借15N示踪、电镜观察等技术手段，从蓝藻氮素的释放过程与规律以及凤眼莲对蓝藻释放氮素的吸收转化效率的角度；从蓝藻对凤眼莲根系形态包括其表面积与超微结构等方面影响的角度；从蓝藻对根系氮素吸收转化能力影响的角度，如根系活力等生理生化指标的变化等方面开展了系列研究。结果表明，凤眼莲庞大的根系表面积和较高的根系活力为其高效吸收水体氮素提供了保障；与蓝藻共培养后，凤眼莲根系细胞长度明显增加，细胞间分隔变得模糊，这有可能会影响胞间连丝的功能，进而对氮素的吸收产生影响；与凤眼莲共培养4周后，80%以上的蓝藻氮素可转迁移转化至凤眼莲植株，且发现凤眼莲根系对蓝藻释放的氮素有短暂的超富集阶段，然后重新分配至茎叶等器官。从多层面不同角度进行了探究与分析，初步揭示了蓝藻促使凤眼莲氮素富集能力升高的内在机理。本研究所得到的结果，可为采用凤眼莲生态工程移除藻华水体氮素提供有力的实践借签和理论参考，具有重要的现实意义和科学意义。