1·Submerged macrophytes are the key factor determining nutritional status of phosphorus in a lake.
沉水植物是影响湖泊磷营养状态的重要因素。
2·So it is necessary to study synthetically the water effect made by submerged macrophytes on polluted water body.
所以系统研究沉水植物对污染水体所产生的水质改善效应是必要的。
3·The water improvement effects from different kinds of submerged macrophytes were studied according to contrastive experiments.
通过试验对比研究不同种类沉水植物对水质的改善效应；
4·Study the biomass impact on water improvement effect by different kinds of submerged macrophytes. The results interpreted from the experiments provide the reference to project.
研究生物量对不同沉水植物水质改善效应的影响，从试验得出生物量的影响结果，为工程应用提供参考；