he uptake by Potamogton crispus of N and P nutrients from, water is related to pHvalue, light intensity, watcr temperature。 ratio of root/shoot biomass, and ratio of nutrientconcentration in the sediment pore water to that in overlaying water. The shoots and leavesof P. crispus take up more NO₃－N than NH₄－N when NO₃－N 0< 35mg/l , but take up more NH₄－N than NO₃－N when NH_4-N 0>35mg/l A combination of strong light intensity, hightemperattire (30℃)under the same conditions (pH: 8.0一9. 5,water temper...