盐度对金鱼藻除氮作用的影响

Effect of Salinities on the Nitrogen Removal Effect of Ceratophyllum demersum

[目的]研究了盐度对金鱼藻生长及除氮作用的影响。[方法]以采自盐碱地水湾的沉水植物金鱼藻为试验材料,试验设5个盐度(S)梯度:0.2、2.0、4.0、6.0、7.5,经过30 d的连续培养和4 d的除氮试验,观察金鱼藻叶茎色泽、抽芽与凋落等生长变化状况。[结果]金鱼藻在水环境盐度S≤4.0时可正常生长,但当盐度S≥6.0时,其生长受到抑制。培养液盐度对金鱼藻去除氨态氮的作用具有显著影响,除氨氮率随盐度的升高而降低,当盐度S>4.0时,金鱼藻基本失去除氨氮能力。金鱼藻具有较强的吸收硝态氮的能力,各盐度组对硝态氮的去除率均高于对氨氮的去除率。金鱼藻还具有良好的去除无机氮的能力。[结论]当养殖用水的盐度S<4.0时,采用金鱼藻可有效降低水环境中的三态氮。

[ Objective ] The purpose was to research the salinity on the growth and nitrogen removal of Ceratophyllum demersum. [ Method ] With the submerged plant C. demersum selected from the water bay of alkaline land, 5 salinity gradients of 0.2, 2.0, 4.0, 6.0, 7.5 were set up to conduct the continuous cultivation test for 30 d and nitrogen removal test for 4 d resp. and the growing status such as leaf-stem color, shoot forth and wilting of C. demersum was investigated. [ Result] C. demersum grew well when the salinity was equal or below 4.0, and its normal growth was restrained when the salinity was equaled or exceed 6.0. The salinity in culture liquid had significant effect on the ammoniacal nitrogen removal of C. demersum. The ammonia nitrogen removing rate was decreased with the increase of the salinity. When salinity was over 4.0, the ammonia nitrogen removing ability of C. demersum was lost basically. C. demersum had strong ability of absorbing the nitrate nitrogen and the nitrate nitrogen removing rate was higher than the ammonia nitrogen removing rate in each salinity treatmnet group. C. demersum also had the good ability of removing inorganic nitrogen. [ Conclusion ] The three-nitrogen （NH4^＋ -N, NO3^- -N, NO2^- -N ）could effectively be reduced by C. demersum when the salinity in aquaculture waters was below 4.0.