营养元素N、P、K对Pb超富集植物吸收能力的影响

为了探索提高Pb(铅)超富集植物吸收能力的方法，该文通过温室土培方法，研究了单一营养元素N、P、K对Pb超富集植物羽叶鬼针草(Bidens maximowicziana)、绿叶苋菜(L.Amaranthus tricolor)和紫穗槐(Sophora japonica)3种植物Pb吸收的影响。营养元素的设计水平为N 0、0.06、0.12、0.18、0.24、0.30 g/kg，P₂O₅ 0、0.06、0.12、0.18、0.24、0.30 g/kg，K₂O 0.08、0.16、0.24、0.32、0.40 g/kg，其他2种元素恒定为0.12 g/kg，土壤铅浓度为800 mg/kg土。结果表明土壤中施入不同水平的营养元素显著影响植物Pb迁移总量。18个处理中羽叶鬼针草、绿叶苋菜与紫穗槐Pb迁移总量最大值与最小值的比值分别为：11.6、10.6、11.9。该试验表明通过调节土壤营养的方法可以提高植物的重金属的迁移总量，利用Pb超富集植物修复Pb污染土壤。3种营养元素对植物的效应不一致，少量的N和K可促进富集植物干质量的增加，促进植物对Pb的吸收，随着N和K水平的增加，植物对Pb的吸收能力降低，但K的抑制作用不如N的显著；土壤供P会降低植物对Pb的吸收，且下降极显著。

Influence of N, P, K nutrient levels on Pb uptake ability of hyperaccumulators

In the greenhouse experiment, 3 varieties of hypertolerant plants: L.Amaranthus tricolor , Sophora japonica and Bidens maximowicziana were grown at different levels of nitrogen(0,0.06,0.12,0.18,0.24,0.30 g/kg), phosphorous(0,0.06,0.12,0.18,0.24,0.30 g/kg), and potassium(0,0.08,0.16,0.24,0.32,0.40 g/kg) to study their performance with regard to lead uptake ability, while the other two-element levels were 0.12 g/kg and soil lead was 800 mg/kg. The results show that N, P, K level had significant effect on plant total lead translocation. The ratio of maximum to minimum value for Bidens maximowicziana,L.Amaranthus tricolor and Sophora japonica were 11.6,10.6,11.9, respectively. But the influence of three elements were not uniform. A little amount of nitrogen and potassium can increase the dry weights of plant, advance the lead uptake of hyperaccumulators, but with the increasing of nitrogen and potassium concentration, the lead uptake of the plants dropped, and dry weights decrease constantly. The little different effect between nitrogen and potassium on lead uptake was that the restraint of the former was more significant than the latter. Additionally, the phosphorus applied to the soil can decrease the lead uptake of the hyperaccumulators dramatically. The conclusion of the research was that if using the plans on the purpose of phytoremediating the lead polluted soil, the total lead translocation can be increased by regulating the soil N, P, K level.