| This paper systematically explored the mechanism of landscape water restoration and water quality assurance of three kinds of submerged plants such as Vallisneria alternifolia,Hydrilla verticillata,and Myriophyllum spp.Reclaimed water is constituent part of the cityscape water.This study consists of two parts:outdoor experiments and indoor experiments.The former is aimd to resesrch the optimal water depth conditions of submerged plant life,and the outdoor experiments use single-factor methods control to explore the optimal light intensity and light quality of submerged plants.Then experimental results applied to landscape water bodies of Xihua Park in Kunming City to verificated.In a larger scale research on water submerged plant in ecological restoration and water quality security mechanism.(1)The result of experimental of four different water depths of removal effect of nitrogen and phosphorus in submerged plants on water is 90cm>65cm>45cm>115cm.when the Planting depth is deep with the underwater illumination is faint,so submerged plants lack of light then corruption and death;Planting depth shallow is not conducive to the survival of the plant,the plant organ will be damage.The results show that when the planting depth around 65-90cm is best with plant service,and the light intensity is in the range of 3000Lx-7500Lx.Appropriate depth made the submerged plants have the best removal effect of nitrogen and phosphorus.The average removal rate of NH3-N was13%.The average removal rate of NO3-N was 42%.The average removal rate of TN was 33%,the average removal rate of TP was 58%.The average removal rate of COD was 32%.Appropriate planting depth the stability of water quality can be maintained for a long time.(2)The effect of removal of nitrogen and phosphorus in water by six different light intensities was 7500Lx>3500Lx>5000Lx>1000Lx>100Lx.When the light intensity was 7500Lx,the average removal rate of NH3-N was 65%,and the average NO3-N was removed was 69%,the average removal rate of TN was 58%,the average removal rate of TP was 42%,and the average removal rate of COD was 46%.Study Show that constant light intensity has more obvious effect on the removal the nitrogen and phosphorus of water,and the removal efficiency is higher than before.When the light is red quality and intensity 7000Lx,the removal of nitrogen and phosphorus in the red light experimental group is better than blue,the average removal rate of NH3-N was 71%,the average removal rate of NO3-N was 47%,and the average TN removal rate was The rate was 48%,the average removal rate of TP was 66%,and the average removal rate of COD was 48%.The submerged plants in the red-blue-irradiated group had worse effects on the removal of nitrogen and phosphorus than the white light-irradiated group.(3)This study main research enzymes,such as SOD,MDA,POD,and CAT in submerged plants.The effect of light on enzyme activity was significant.With light intensity rising the activity of each enzyme in Foxtail was increased.The four enzymes was increased to 1002.18 Ug-1.FW.h-1,11.86 mmol.g-1FW,188.89 μg.g-1.FW.min-1,188.89 Ug-1.FW.min-1;Hyphora in light intensity,the highest enzyme activity was at 2500 Lx,followed by 1373.58 Ug-1.FW.h-1,19.69 mmol.g-1FW,99.3 μg.g-1.FW.min-1,and 50 U.g-1.FW.min-1.The highest enzyme activity was in the light intensity of 7500Lx,and the activity of four enzymes was 1153.49 Ug-1.FW.h-1,20.63 mmol.g-1FW,120.69μg.g-1.FW.min-1,97.11 Ug-1 in order..FW.min-1,(4)The effects of light quality on the activities of SOD,MDA,POD and CAT enzymes in the three submerged plant species were significant.Blue light could increase the activity of the myriophyllum enzymatic activity.The highest activity of the four enzymes was 798.23 Ug-1.FW.h-1,29.27mmol.g-1FW,27.369μg.g-1.FW.min-1,33.61Ug-1.FW.min-1;Blue light can also increase the enzyme activity of Hydrilla,the activity of four enzymes was 1109.22 Ug-1·FW.h-1,28.57mmol.g-1FW,147.80μg.g-1.FW.min-1,14.72Ug-1.FW.min-1;Vallisneria is more suitable for red light quality,and activity of four enzyme was 1121.75 Ug-1.FW.h-1,14.41 mmol.g-1 FW,153.41 μg.g-1.FW.min-1,46.44 Ug-1.FW.min-1.(5)Submerged plants can effectively maintain the water quality of Xihua Park landscape waters with the highest average annual transparency of 140 cm,the annual average concentration of NH3-N was 0.522 mg/L,and the average annual concentration of NO3-N is 0.386 mg/L;The annual average concentration was 1.367 mg/L;the annual average concentration of TP is 0.041 mg/L and COD was 19.43 mg/L.When the transparency of the water is high,the plant grows vigorously and the stability of the water ecosystem is strong. |
