北京市典型土著沉水植物对水体中硝酸盐和正磷酸盐的耐受性研究

Study on the tolerance of typical native submerged plants to nutrient salts in Beijing

以北京市3种典型土著沉水植物轮叶黑藻、狐尾藻和金鱼藻为研究对象,构建模拟水生生态系统,研究3种沉水植物对水体中NO-3和PO4^3-的耐受性并确定其耐受范围.同时,对植物体内过氧化氢酶、丙二醛、叶绿素和蛋白质4种指标进行检测.结果表明,轮叶黑藻对NO-3具有较强的耐受性,耐受浓度可达8 mg·L^-1,金鱼藻和狐尾藻次之,耐受浓度为3~5 mg·L^-1;狐尾藻对PO4^3-的耐受性最差,耐受浓度约为0.2 mg·L^-1,轮叶黑藻和金鱼藻的耐受性相当,当PO4^3-浓度达到0.4 mg·L^-1时开始出现显著胁迫.因此,在本研究的实验条件下,当水体NO-3浓度<5 mg·L^-1、PO4^3-浓度<0.2 mg·L^-1时,建议3种沉水植物同时种植;当NO-3浓度>5 mg·L^-1时,建议种植轮叶黑藻;当PO4^3-浓度为0.2~0.4 mg·L^-1时,建议种植轮叶黑藻和金鱼藻.研究结果可为北京市再生水补给河湖水库的水生态修复及其沉水植物群落的构建提供一定的理论指导.

Three typical native submerged plants(i.e., Hydrilla verticillate, Ceratophyllum demersum L., and Myriophyllum verticillatum L.) were selected and their tolerabilities to NO^-3 and PO4^3- were studied and the tolerance range was determined by building simulation aquatic ecosystems. The tolerabilities were determined via the analysis of four indicators of POD, MDA, chlorophyll and protein. The results showed that Hydrilla verticillate had strong tolerance to NO-3 and its tolerance concentration reached 8 mg·L^-1, followed by Cd and Myriophyllum verticillatum L. with a tolerance levels of 3~5 mg·L^-1. In addition, Myriophyllum verticillatum L. exhibited the lowest tolerance to PO4^3- with about 0.2 mg·L^-1, while as to Hydrilla verticillate and Ceratophyllum demersum L., the significant stress began to occur when the PO4^3- concentration reached 0.4 mg·L^-1. Therefore, under the experimental conditions of this study, three submerged plants were suggested to be planted simultaneously when the concentration of NO-3 in water was less than 5 mg·L^-1 and PO4^3- was less than 0.2 mg·L^-1. However, Hydrilla verticillate was given priority to the cultivation when the concentration of NO-3 was > 5 mg·L^-1, and the priority was given to the cultivation of Hydrilla verticillate and Ceratophyllum demersum L. when the concentration of PO4^3- was 0.2~0.4 mg·L^-1. The results can provide some theoretical guidance for the water ecological restoration and the construction of submerged plant community of the regenerated water supply river and lake reservoirs in Beijing.