外源氨基酸对龙葵修复Cd-PAHs污染土壤的强化作用

Promotion effects of exogenous amino acids on phytoremediation of Cd-PAHs contaminated soils by using hyperaccumulator plant Solanum nigrum

采用室内盆栽试验的方法,研究外源半胱氨酸、谷氨酸、甘氨酸及其复合处理对超富集植物龙葵(Solanum nigrum)修复镉-多环芳烃复合污染土壤的影响。结果表明:各浓度水平的单因素处理对植物株高及地上部干重并没有显著影响(P>0.05),而复合处理则具有显著的促进作用(P<0.05);各处理能够显著增强龙葵对镉的吸收和富集能力,其中半胱氨酸处理使重金属提取率分别达到1.80%及1.83%,与对照相比提高了0.80及0.83倍;研究发现甘氨酸、谷氨酸及半胱氨酸复合处理能够促进镉及多环芳烃在土壤环境中的去除作用,且0.3 mmol.kg-1甘氨酸+0.3 mmol.kg-1谷氨酸+0.3 mmol.kg-1半胱氨酸处理效果最佳,与对照相比龙葵地上部Cd含量增加了1.26倍,土壤多环芳烃总量的去除率提高了4.46倍;可见,外源PCs组成物质能够强化植物修复低浓度镉-多环芳烃复合污染土壤,具有成为植物修复重金属-有机复合污染高效强化剂的潜力。

An indoor pot experiment was conducted to study the effects of exogenous cysteine, glutamate, glycine, and their combinations on the Solanum nigrum pytoremediation of Cd- and PAHs contaminated soils. Single factor treatments with test amino acids had less effects on the S. nigrum plant height and its shoot dry weight （ P 〉 0. 05 ）, while multi-factor treatments promoted the plant height and shoot dry weight significantly （P 〈 0. 05 ）. All the treatments increased the Cd uptake and accumulation by the plants, with the extraction ratios of plant Cd in treatment cysteine reached as high as 1.80% and 1.83% , being 0. 80-fold and 0. 83-fold higher than the control, respectively. The combined application of eysteine, glutamate, and glycine promoted the removal of soil Cd and PAHs, with the best effect in treatment 0.3 mmol · kg^-1 cysteine ＋ 0.3 mmol · kg^-1 glutamate ＋ 0. 3 mmol · kg^-1 glycine, in which, the Cd concentration in plant shoot and the removal rate of soil PAHs increased by 1.26-fold and 4.46-fold, respectively, compared with the control. It was suggested that exogenous cysteine, glutamate, and glycine could promote the phytoremediation of low concentration Cd-PAHs contaminated soils, and have a promising fu- ture in contaminated soil phytoremediation.