| Since the21st century, water and soil loss severity of naturalenvironment had basically under control in china, andsolve the problem of food and clothing is not the principalcontradiction in china. With the improving of the living standard,humans’ spiritual culture is increasing and beginning to accept theaesthetic idea of original ecology and close-to-nature. However thewater ecological system had been damaged severely caused byrubbish, waste water, pesticide and chemical fertilizer, whichreleased from industrial and agricultural production. According tothe china’s environmental bulletin2012, the water eutrophication isstill a major environmental problem in china. Therefore, four typesof hygrophyte including Phragmites australis, Scirpus triqueter,Mentha haplocalyx and Oenanthe javanica were selected fromShanxi province to simulate artificial wetland with differentconcentration of eutrophication water. To study the removalability of wetland plant and combination to eutrophication water.Screened out better removal and adapt to local wetland plant andcombination, and give full play to construct clean the ecotypewatershed to remarkably improve ecotope, and give the base toprotect water environment. The results as follows:(1) The four type of plant were grown normal during the experiment. The plant height of Phragmites was variation highest,the average height from24.13cm increased to56.92cm under mildtreatment, from22.21cm increased to58.64cm moderate mildtreatment, and increased by29.86cm under severe treatment.Scripus triqueter was putting out new shoots and Bengalwaterdropwort herb had a thriving root system and the stem wasoverstriking significantly, over90%of Mentha haplocalyx hadflowering during the experiment.(2) The chlorophyll fluorescence parameters showed that theradiation use efficiency of water fennel was increased with theeutrophication aggravated, which could damage plant and affectedphotosynthesis of Menta and Phragmites, as well as Scripustriqueter.(3) Under mild treatment, TP uptake ability of Phragmites andScripus triqueter were higher than the other two plants; Scripustriqueter had the highest COD, TN uptake ability and Menta forNH4+-N. Under moderate treatment, Scripus triqueter had thehighest TP uptake ability and significantly higher than Water fenneland Phragmites（P﹤0.05）; Phragmites had the highest TN uptakeability and significantly higher than Water fennel and Menta（P﹤0.05）; Menta had the highest NH4+-N uptake ability and Scripustriqueter for COD. Under severe treatment, there was no differencefor TN uptake among the four kinds of plant（P﹥0.05）; Scripustriqueter had the highest TP, COD uptake ability and Water fennelfor NH4+-N uptake.(4) Under mild treatment, Phragmites+Scripus triqueter hadhigher uptake ability to TP、TN、NH4+-N than Phragmites+Scripus triqueter+Menta, except to COD. But Phragmites+Scripus+Mentahad significantly higher uptake ability to TP than other three kind ofplant combination under moderate treatment; and Phragmites+Scripus triqueter for NH4+-N. The difference was below5%for TN、COD uptake ability by four kind of plant combination. Under severetreatment, Phragmites+Scripus triqueter had the advantage toremove NH4+-N, Phragmites+Scripus triqueter+Menta and Scripustriqueter+Menta to COD. There had the ideal purifying effect to TPand TN by four kind of plant combination, the difference was lessthan4%.(5) To sum up, the best uptake efficiency of TP and TN in theeutrophic water was Phragmites australis. Mentha haplocalyx andOenanthe javanica had a better uptake efficiency of NH4+-N,Scirpus triqueter had obvious advantages to removal of COD. Plantscollocation may be lead to competition and inhibition of growth,affecting purification effect. May also be due to the concentrationlimit,compared with the single plant,Purification of plantcombinations had no obvious advantage under mild treatment. Butwith the increase of concentration of eutrophication, Purificationadvantages of plant combinations highlighted gradually. |
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