8种观赏水湿生植物对重金属Cd和Pb的吸收固定能力

Capacity for absorbing and fixing heavy metal of Cd and Pb of eight species of ornamental aquatic plants

水体沉积物是水体污染物的重要汇和源,水湿生植物具有净化水体的重要功能。采用人工污染土壤的盆栽方法,对8种不同生活型水湿生植物吸收富集土壤Cd和Pb的分析结果发现,莎草地上部分和地下部分Cd含量随着土壤中Cd浓度的增加而增加,在土壤中Cd添加浓度(干重)为5 mg·kg-1时,Cd的累积浓度分别1.13 mg·kg-1DW和1.63 mg·kg-1DW;供试植物的地下部分Pb含量是地上部分的10~20倍,莎草和香蒲的地下部分Pb含量在高浓度Pb土壤中达到20 mg·kg-1DW左右。黄花鸢尾、莎草以及睡莲这3种植物对土壤Cd的转运系数和富集系数大于1,结合生物量因素可以认为,莎草具有富集土壤Cd能力,而莎草和香蒲具有固定土壤Pb的能力。

Aquatic sediment is the main source of water pollutant. Aquatic plants have the ability to purify water. Potted planting by polluted soil was conducted to analyze the ability to absorb Cd and Pb by eight different aquatic plants. The results indicated that the concentration of Cd in Cyperus prolifer increased with the concentration in soil. When the concentration of Cd in soil is 5 mg · kg^-1DW,the accumulated concentration is 1. 13mg·kg^-1DW and 1. 63 mg·kg^-1DW in aboveground parts and belowground parts respectively. The content of Pb in belowground parts of experimental plants are 10 to 20 times to the aboveground parts. The content of Pb in belowground parts of Cyperus prolifer and Typha orientalis planted in soil with high concentration of Pb reached 20mg·kg^-1DW. Transfer and accumulation coefficient of Cd in soil of Iris wilsonii,Cyperus prolifer,Nymphaea are larger than 1,which suggested that Cyperus prolifer has the ability to accumulate Cd from soil while Cyperus prolifer,Typha orientalis have the ability to capture Pb from soil.