Studies On The Purification Of Aquatic Plants And Its Utilization In Ecological Landscape Designing Of Water Scenery

Aquatic plants were one of the important factors in water scenery designing and benefit to improve and maintain water quality effectively. There are significances of research of aquatic plants in landscaping and ecology, as well as improving water quality. On the basis of investigating the resource and utilization of aquatic plants in zhejiang, China, the paper selected some ornamental aquatic plants to study their purification characters, such as Alisma plantago-aquatica, Polygonum on'entale, Nymphoides cristata, et al. The influence of aquatic plants to water scenery and water self-purification was discussed. In addition, according to the ecological and landscape ecological principles, this study showed some preliminary researches on the proper use of aquatic plants. The result were summarized as follows:1. There are rich resources of aquatic plants in Zhejiang province. More than 30 species of aquatic plants in garden use, including cultural and wild plants, which had the characteristics of ornamental and purification in water scenery. There were many aquatic plants have the potential utilization in water garden, such as Lythrum salicaria, Scirpus validus cv. Zebrinus, Alisma plantago-aquatica, Houttuynia cordate, Vallisneria natans, et al.2. Lythrum salicaria removed P effectively in eutrophic water with different levels of TP concentrations. The plants were growing well from the TP concentrations of 0 mg L"1 to 0.4 mg L"1 in culture solution. During the 30d experimental period, the highest removal percentage of TP in eutrophic water(TP = 0.4 mg L'1) was more than 98%. Compared with the control plant (Eichhomia crassipes), the P removal rate of Lythrum salicaria was higher with the TP concentrations of 0.05 mg L~1and0.4mg L"1. In the first 10 days, the concentration of TP in the solution decreased dramatically in Lythrum salicaria. The results showed that the removal percentage of TP positively correlated to the TP concentrations. It indicated the potential purification ofLythrum salicaria in eutrophic water, and supported its uses in water scenery design.3. The combinations of the various aquatic plants showed good maintainability in water garden. The concentrations of TP, TN were kept lower effectively in the experimental pool II (planted with emersed aquatic plants) and pool En (floating and floating leaf aquatic plants and submerged aquatics) The concentration of TP and TN was relatively higher in pool I which only planted with Potamogeton crispus.4. Furthermore, the purify functions in water with the submerged aquatic plants were realized. Considering the status of ignoring aquatic seeds in water scenery designing and utilization, we suggested it is necessary to use aquatic seeds in further designs.5. Following the general principles of landscape design and the experimental results showed above, we practiced several actual landscape designs which done in Shanghai and Hangzhou. The related data of water quality, including the chroma, pH value, COD and DO, were tested from the water scenery in Hangzhou. Results showed that all the data were below the national standards of water quality for landscape and amusement. It satisfied the desires of enjoying and playing of the inhabitants.Emphasis is put on the appropriate extension and utilization of aquatic plant resources. Refer to the methods of eutrophical prevention and cure in lakes, we discussed the status of aquatic plants in utilization as well as the measures to keep the healthy quality of water scenery. We regarded the ecological landscape designing for water scenery should be stereoscopic.