Effects Of Acid Rain And Eutrophication Combined Stress On Biochemical Characteristics And N、P Absorption Of Acquatic Plants

Based on the hydroponic experimental method, effects of the simulated acid rain（two treatmentlevels:pH2.0and pH3.5）and eutrophication combined stres（sN1TLI=42.44、N2TLI=60.66、N3TLI=80.62） are investigated on physiological and biochemical characteristics and N、Pabsorption of A.gramineus、Saururus chinensis and Oenanthe javanica. The results couldprovide a reference for aquatic plants in the simulated acid rain and eutrophication combinedstress absorbing the influence of different forms of nitrogen ways and mechanism.Main resultsare described as follows:（1）Acid rain treatment increase leaf relative electrolytic rates of three plants. With increasingfrequency of acid rain,the cell membrane permeability increases. With increasing degree ofeutrophication, the cell membrane permeability of Saururus chinensis and Oenanthe javanicaincrease,but that of A.gramineus difference is small.（2）With increasing degree of eutrophication,the root activities of A.gramineus and Saururuschinensis first increase and then decrease,but the root activity of Oenanthe javanica increase.The root activity of A.gramineus and Saururus chinensis increase with the acidic concentration,but that of Oenanthe javanica reduce with acid treatmen.（3） With increasing degree of eutrophication, the leaf nitrate reductase activity of A.gramineusand Saururus chinensis first increase and then decrease.The leaf nitrate reductase activity ofOenanthe javanica increase quickly.Under acid rain stress, the leaf nitrate reductase activities ofthree plants all reduce under N1an N3level.But to N2level, the leaf nitrate reductase activityof A.gramineus and Saururus chinensis increase.（4） With increasing level of eutrophication,TP and TN contents of leaves in A.gramineus andSaururus chinensis first increase and then reduce quickly,TP and TN contents in Oenanthejavanica increase.TP and NH₄⁺-N contents of three plants reduce with acid rain treatment times,TN contents in Saururus chinensis and Oenanthe javanica reduce with acid treament times,andTN contents in A.gramineus are less affected by acid rain treament times.（5） A.gramineus is removal rate of TP, with increasing initial concentration of TP, increasesfirst and then decreases; Its removal rate of TN decreases with increasing initial TNconcentration; the removal rate of NH₄⁺-N increase with increasing initial concentration of NH4＋-N; After acid rain treatment, A.gramineus in addition to higher removal rate of NH₄⁺-N, TPand TN removal rate reduced. Saururus chinensis is TP removal rate decreases with theincrease of initial concentration of TP; As the initial concentration of TN, the TN removal ratepresents the first rise again; NH₄⁺-N removal rate with increasing initial concentration of NH＋4-N and lower; Acid rain has lowered, Saururus chinensis removal ability after treatment.Oenanthe javanica for TP removal ability as the TP higher initial concentration; The TNremoval rate is not affected by initial concentration of TN changes; NH₄⁺-N removal rate islower as the initial concentration increased first, then decreased; Oenanthe javanica is removalability is greatly influenced by acid rain treatment. （6） A.gramineus could be planted in high NH₄⁺-N content eutrophic water body with acid rainpollution. Saururus chinensis could be planted in high TN content eutrophic waterbody withacid rain. Oenanthe javanica could be planted in high TPcontent eutrophic waterbody withoutacid rain pollution.