Effects Of Three Submerged Macrophytes On Phosphorus In The Sediment

From April to October in 2005, three different macrophytes ,Potamogeton maackianus Myriophyllum spicatum and Vallisneria spiralis,, were cultured in sediments collected from the shuiguo lake, one part of east lake which was regard as the eutrophic water. The experiments were carried out in Wuhan botanical garden, Chinese academy of Sciences. During the experiments, the variation of chemical forms of phosphorous in sediments brought by the interspecific difference and the growth traits of three submerged macrophytes were studied. The results were as follows:1. The three submersed macrophytes: P. maackianus, M. spicatum and V. spiralis growed well in the high eutrophic sediment. The results indicated that all the plants could effectively decrease the content of phosphorus in porewater, total phosphorus (TP) and different chemical forms of phosphorus in the sediment, especially V. spiralis. The three submersed macrophytes can change the phosphorus in the sediment through shoot oxygenation and nutrition allocation or some other mechanism. Though the effection mechanism is complex, the submersed macrophytes really reduce the content of phosphorus to the different extend during their growing period. Periodical harvesting senescent submersed macrophytes may be an important measure which can down the level of the internal phosphorus loading.2. The pronounced compacts of interspecific difference on the phosphorus pools in sediment were found in these submersed macrophytes too. This differences maybe attributed to the morphological and physiological differences among species (i.e., r/s ratio, growth form and shoot oxygenation capabilities)...