Absorbability of wetland plants on N and P from eutrophic water

The absorbability of wetland plants on nitrogen and phosphorus was investigated by means of nutrient solution incubation. The results indicated that mean biomass of wetland plant ranged from 9.31 to 49.53 g/plant (dry weight),and shoot to root ratio ranged from 1.21 to 3.09. The above-ground biomass of Canna indica,Coix lacryma-jobi,Eichhornia crassipes and Phragmites australis was quite high, while Ophiopogon japonicus had the lowest above-ground biomass. The concentration of nitrogen (N) and phosphorus (P) of above-ground tissue ranged from 22.13 to 33.03 (mg/g) and 2.53 to 5.38 mg/g (dry weight),respectively. The amount of nitrogen and phosphorus uptaked by wetland plant ranged from 252.99 to 1279.98 and 23.55 to 251.83 mg/plant,respectively, which was mainly determined by plant biomass. The removal rate of nitrogen and phosphorus of wetland plant ranged from 10.91% to 59.32% and 50.13% to 87.26%, respectively. These results showed that Canna indica,Coix lacryma-jobi,Eichhornia crassipes and Phragmites australis had stronger absorbability on nitrogen and phosphorus indicating they are promising plants to purify water and eliminate eutrophication.