Abstract:

In order to screen suitable plants that have the strong purification in Erhai Lake out, four kinds of indigenous plants,Juncus effusus, Acorus calamus, Hemerocallis fulva and Isodon inflexus had been made into the plant floating bed to study their purified effect on nitrogen and phosphorus. It turned out that all four plants could keep their strong life force in the Erhai Lake and their biomass increased obviously. The most increased was Isodon inflexus Hemerocallis; fulva follows and the next was Acorus calamus; Juncus effusus was the least increased plants. All the four plants could remove the TN and TP obviously. The removal rates of TN were over 65%. The removal rates of TN achieved by Juncus effusus, Acorus calamus, Hemerocallis fulva Linn and Isodon inflexus were 69.8%, 80.03%, 72.60%，85.08%, and all of them were obviously higher than the control (37.10%). And the removal rates of TP was also obviously higher than contrast, which were 74.39%, 80.04%, 72.88%, 78.01% respectively. The examination proved that all of four plants had a good purified effect in the Erhai Lake, so they could be widely used in purifying the water of Erhai Lake in Dali in the future.

Key words: indigenous plants, Erhai Lake water, purification