Effects Of PH On Submerged Plants In Removing Different Forms Of Nitrogen From Water

To better understand the effects on the removal of different forms of nitrogen of submerged plant on water. This paper studied the removal efficiency and mechanism of pH on submerged plant (Vallisneria natans and Myriophyllum verticillatum) to different forms of nitrogen in the water body based on absorb the kinetic experiments and simulation experiment, by analyzing the absorption kinetics parameters of submerged plants, total nitrogen (TN), ammonia nitrogen (NH4+-N), nitrate (NO3-N), and plant biomass, Nitrogen accumulation, nitrate reductase (NR) activity, the results obtained were as follows:1、There were significant effects in the uptake dynamics characteristics of NH4+-N and NO3--N of pH to submerged plant (Vallisneria natans and Myriophyllum verticillatum). The results showed that the affinity of nitrogen and maximum absorption rate of Vallisneria natans under weakly acidic (pH5.5) conditions for NH4+-N and NO3--N were significantly higher to neutral and alkaline (pH8.5,9.5) conditions(P<0.05), and weak alkaline conditions of that preferably to neutral conditions. Then the affinity of nitrogen and maximum absorption rate of Myriophyllum verticillatum under neutral conditions were significantly higher to weak acid and alkaline conditions(P<0.01), while the pH8.5group had a higher affinity and maximum absorption rate than pH5.5group. Vallisneria natans and Myriophyllum verticillatum had a greater absorption capacity for ammonium than nitrate under the same pH conditions.2、PH had a certain impact in removing different forms of nitrogen on water of Vallisneria natans and Myriophyllum verticillatum. Vallisneria natans had the best removal capacity to NH4+, NO3-and TN in pH5.5, and generally significantly higher than other pH treatments(P<0.05). Myriophyllum verticillatum had the best removal capacity to NH4+, NO3-and TN in pH7, and generally significantly higher than pH5.5and pH8.5(P<0.05).3、PH had some influence on TN inventory of different submerged plants. At the end of the experiment, the nitrogen accumulation of Vallisneria natans and Myriophyllum verticillatum were significantly higher before the experiment(P<0.05). And the nitrogen content of Vallisneria natans and Myriophyllum verticillatum were presented as T3>T2>T1in different water. The nitrogen accumulation of Vallisneria natans and Myriophyllum verticillatum had differences in water environment with different pH, which Vallisneria natans had a higher nitrogen accumulation in pH5.5, while Myriophyllum verticillatum had a higher nitrogen accumulation in pH7.The nitrogen accumulation of Myriophyllum verticillatum were significantly higher than Vallisneria natans in defferent pH(P<0.05).(The concentrations of ammonium and nitrate of T1were3.06mg/L、0.94mg/L; The concentrations of ammonium and nitrate of T2were2mg/L、2mg/L; The concentrations of ammonium and nitrate of T3were0.94mg/L、3.06mg/L).