巨大芽孢杆菌与柠檬酸联合强化青葙修复镉污染土壤研究

为研究柠檬酸和巨大芽孢杆菌对青葙修复Cd污染土壤的影响,筛选最佳添加量以提高修复效率,采用盆栽试验,以正交方式研究了添加不同浓度的柠檬酸(Citric acid)(0、2.5、5、7.5 mmol·kg~(-1)和10 mmol·kg~(-1))和巨大芽孢杆菌(Bacillus megaterium)(0、108、109cfu·kg~(-1)和1010cfu·kg~(-1))对青葙(Celosia argentea Linn)修复Cd污染土壤的强化作用。结果表明:与对照处理(无柠檬酸和巨大芽孢杆菌添加)相比,柠檬酸和巨大芽孢处理使青葙各部分生物量、Cd含量及Cd积累量均增加。其中,109cfu·kg~(-1)的巨大芽孢杆菌+5 mmol·kg~(-1)柠檬酸处理增加效果最显著,使青葙叶、茎、根及地上部的生物量分别比对照处理增加48.7%、43.3%、78.8%和45.6%;叶、茎及根中的Cd含量较对照处理分别增加75.8%、76.3%和74.6%;地上部Cd积累量增加159%。该处理的青葙地上部Cd积累量为1.03 mg·pot-1,Cd去除率高达21.0%。因此,添加柠檬酸和巨大芽孢杆菌浓度为5 mmol·kg~(-1)和109cfu·kg~(-1)的处理最有利于提高青葙对Cd污染土壤的修复效率。

Bacillus megaterium and citric acid enhanced the remediation of Cd-contaminated soil by Celosia argentea Linn

To study the effects of citric acid and Bacillus megaterium on the remediation of Cd-contaminated soil by Celosia argentea and optimize their application rates to improve remediation efficiency, a pot experiment using a 4×4 factorial design was conducted to study the effect of citric acid(0, 2.5, 5, 7.5 mmol·kg^-1, and 10 mmol·kg^-1) and B. megaterium(0, 10⁸, 10⁹ cfu·kg^-1, and 10¹⁰ cfu·kg^-1) on phytoremediation of Cd-contaminated soil by C. argentea. The results indicated that the application of B. megaterium and citric acid significantly increased the biomass, Cd concentration, and Cd accumulation in the roots, stems, and leaves of C. argentea compared with the control(without B. megaterium and citric acid addition). Application of 10⁹ cfu·kg^-1 B. megaterium and 5 mmol·kg^-1 citric acid had the best effects, and increased leaf, stem, root, and shoot biomass by 48.7%, 43.3%, 78.8%, and 45.6%, respectively compared with the control. With 109 cfu·kg^-1 B. megaterium + 5 mmol·kg^-1 citric acid treatment, the Cd concentrations in the leaves, stems, and roots increased by 75.8%, 76.3%, and 74.6%, respectively, and Cd accumulation in shoots increased by 159%. The highest Cd accumulation in the shoots and the rate of Cd removal were 1.03 mg·pot^-1 and 21.02%, respectively when 10⁹ cfu·kg^-1 B. megaterium and 5 mmol·kg^-1 citric acid were applied to the soil. Therefore, the application of citric acid and B. megaterium at a concentration of 5 mmol·kg^-1 and 10⁹ cfu·kg^-1, respectively is most effective for improving the remediation efficiency of Cd-contaminated soil using C. argentea.