金鱼藻(Ceratophyllum demersum)是剑湖广泛分布的沉水植物,对不同采样点不同生长季节金鱼藻体内的总氮、硝态氮和氨态氮含量进行了测定和比较.结果显示,环境中的氮源直接影响金鱼藻对氮素的吸收利用,在污染严重的永丰河入湖口,金鱼藻体内的总氮和氨态氮含量较高.在污染相对较小的格美江入湖口,金鱼藻体内的硝态氮含量较高,环境中高浓度的氨态氮会抑制金鱼藻对硝态氮的吸收利用.金鱼藻体内氮素水平随季节变化明显,3～5月金鱼藻体内不同形态氮含量均高于7月.%Ceratophyllum demersum was widely distributed in Jian Lake in Yunnan province. Total nitrogen, nitrate nitrogen and ammonia nitrogen of C. Demersum collected from different sites in different growth seasons were detected and compared. Results showed that nitrogen source in the environment directly affected the absorption and utilization of nitrogen of C. Demersum. Total nitrogen and ammonia nitrogen was high in C. Demersum in Yongfeng River which was seriously polluted. Nitrate nitrogen was high in C. Demersum in Gemei River. High concentration of ammonia nitrogen in environment could inhibit uptake and transformation of nitrate nitrogen. The nitrogen level in C. Demersum changed obviously with the seasons; and nitrogen content of different forms was higher in March to May than in July.
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