小叶榕对重金属复合污染模拟湿地的适应性及修复效果研究

Adaptability and Remediation of Ficus microcarpa to Simulated Wetland Polluted by Heavy Metals

【目的】探究小叶榕对Pb、Cd、Cu复合污染模拟湿地的适应性及修复潜力,为利用植物修复技术进行重金属复合污染湿地的修复提供理论依据。【方法】以小叶榕(Ficus microcarpa)为研究对象,采用盆栽试验模拟湿地环境,以不添加重金属为对照(CK),探究T_(1)(5 mg/L Cd+50 mg/L Pb+100 mg/L Cu)、T_(2)(10 mg/L Cd+100 mg/L Pb+200 mg/L Cu)、T_(3)(20 mg/L Cd+200 mg/L Pb+400 mg/L Cu)3个复合污染水平对小叶榕生长、养分和重金属吸收累积的影响。【结果】3种复合污染水平均显著提高小叶榕株高及总生物量,但对地径无显著影响;T_(1)、T_(2)处理根部、地上部生物量及质量指数较CK显著增加,T_(3)处理无显著变化。小叶榕根部P、K含量及全株K含量随污染浓度升高呈上升趋势;3种处理均显著增加植株N、P、K的全株积累量。随着污染浓度提高,小叶榕更倾向于将吸收的Pb、Cd富集在根部,而将Cu更多地往地上部转运;小叶榕对Pb、Cd、Cu吸收累积随着重金属浓度升高逐渐增加,且植株体内Cd含量的增长幅度在3个重金属中最大。加权隶属函数法结果表明小叶榕在T_(3)处理时对重金属具有最强的吸收积累能力,但生长势小于T_(1)、T_(2)处理。【结论】小叶榕在Cd、Pb、Cu含量分别不高于20、200和400 mg/kg的复合污染模拟湿地环境中生长良好并且对其具有较强的修复效果,可作为湿地修复的备选植物。

[Objective]This study aims to explore the tolerance and restoration potentials of Ficus microcarpa to simulated wetland polluted by Pb,Cd and Cu,thus providing theoretical basis for the remediation of heavy metal combined polluted wetland by phytoremediation technology.[Method]Ficus microcarpa was studied in a simulated wetland environment under potted conditions,with no heavy metals added as the control(CK),to evaluate the effects of three combined pollution levels of T_(1)(5 mg/L Cd+50 mg/L Pb+100 mg/L Cu),T_(2)(10 mg/L Cd+100 mg/L Pb+200 mg/L Cu)and T_(3)(20 mg/L Cd+200 mg/L Pb+400 mg/L Cu)on the growth,nutrient,heavy metal absorption and accumulation of Ficus microcarpa.[Result]Three combined pollution levels significantly increased the height and total biomass of Ficus microcarpa,but had no significant effect on the ground diameter.Compared with CK,the biomass and mass index of root and shoot in T_(1) and T_(2) treatments were significantly increased,while there was no significant change in T_(3) treatment.The contents of P and K in the root and K in the whole plant increased with the increase of pollution concentration.All the treatments significantly increased the accumulation of N,P and K.With the increase of pollution concentration,the Pb and Cd absorbed by Ficus microcarpa were enriched in the roots and Cu was transported to the aboveground part.The absorption and accumulation of Pb,Cd and Cu in Ficus microcarpa gradually increased with the increase of heavy metal concentration,and the increment rate of Cd content was the largest among the three heavy metals.The results of weighted membership function showed that T_(3) treatment had the strongest ability to absorb and accumulate heavy metals,but the growth potential was smaller than that of T_(1) and T_(2) treatments.[Conclusion]Ficus microcarpa had good adaptability and restoration effect to the simulated wetland environment with the contents of Cd,Pb and Cu less than 20,200 and 400 mg/kg,respectively,and it can be used as an alternative plant for wetland restoration.