硝酸盐氮对紫背浮萍氨耐受能力的影响

为了分析硝酸盐氮对紫背浮萍氨耐受能力的影响，该文通过在4个系列氨氮培养液中加入不同水平硝酸盐氮，研究了不同情况下紫背浮萍相对生长速率、叶面积等的变化．研究结果表明，在没有硝酸盐氮的情况下，紫背浮萍的相对增长速率和叶状体大小随氨浓度增加而逐渐降低，能够耐受的最大氨质量浓度约为400mg/Lρ(NH4^ -N)]．在硝酸盐存在情况下，紫背浮萍生长则可耐受500mg/Lρ(NH4^ -N)]，并且相同氨氮质量浓度下，硝酸盐存在使紫背浮萍相对增长速率和叶状体面积均增加．从该研究结果来看，水中硝酸盐氮的存在可提高紫背浮萍对氨的耐受性．

Improvement on tolerance of Spirodela polyrrhiza to ammonia at presence of nitrate

The response of Spirodela polyrrhiza to ammonia with the existence of different concentrations of nitrate was investigated in this study. Four series media with different concentrations of ammonia and nitrate were set up in experiments. The relative growth rate and the frond area of S. polyrrhiza in different conditions were studied. The results showed that the relative growth rate and the frond area of S. polyrrhiza decreased with the increasing concentration of ammonia. The maximum concentration of ammonia that S. polyrrhiza can bear is about ρ(NH+4-N) of 400 mg·L-1 without nitrate. But S. polyrrhiza can bear the concentration of ammonia up to ρ(NH+4-N) of 500 mg·L-1 in the presence of nitrate. The relative growth rate of S. polyrrhiza at high ammonia level ρ(NH+4-N)>100 mg·L-1] with nitrate was clearly higher than ones without nitrate. The area of fronds with nitrate was larger than ones without nitrate at higher ammonia level ρ(NH+4-N)>300 mg·L-1]. It demonstrated that the presence of nitrate could enhance the tolerance of S.polyrrhiza to ammonia.