我们曾在1980-1981年研究了红萍对外界水体中钾的吸收,发现和明确了红萍对外界水体中低浓度的钾有强烈的吸收,富集作用。其吸收钾的临界高峰在0.85ppmK_2O左右。对水液中0.5-5ppm的钾每昼夜可吸收50%。但是,养殖红萍除池塘、河沟等天然水体外,多数养殖在水稻田中。水稻田水层较浅,整个体系呈一种水-土系统状 In 1980-1981, we studied the absorption of Potassium in the water bodies of Rhododendron macrophylla. We found and clarified that Rhododendron strongly absorbed and enriched the potassium in low concentrations in the water of the outside world. The critical peak of its absorption of potassium is about 0.85ppmK_2O. 0.5-5ppm of potassium in water can absorb 50% of the diurnal day and night. However, farmed red duckweed in addition to ponds, river ditches and other natural water, the majority of farming in paddy fields. The water layer of paddy field is shallow, the whole system is a water-soil system