外源有机酸对美人蕉耐性和Cr吸收、迁移的影响

采用营养液培养试验,研究外源有机酸(柠檬酸、草酸和酒石酸)对Cr污染水体中美人蕉(Canna indicaL.)的耐性、对Cr的吸收和迁移能力的影响。结果表明,各有机酸均不同程度地增强了美人蕉的耐性,促进Cr吸收和向地上部迁移。不同有机酸和同种有机酸不同浓度(4,8,16 mmol/L)的影响效果不尽相同。就耐性特征而言,16 mmol/L的草酸能够明显提高美人蕉生物量和促进根系生长,其影响效果要大于柠檬酸和酒石酸;就Cr吸收和迁移特性而言,影响大小为柠檬酸>酒石酸>草酸,尤以16 mmol/L的柠檬酸效果最为显著,而酒石酸和草酸分别在8 mmol/L,16 mmol/L时最利于Cr的吸收和迁移。因此,在本试验条件下16 mmol/L的柠檬酸较适合Cr污染水体的植物修复。

Effects of Exogenous Organic Acids on Cr Tolerance, Uptake and Translocation by Canna indica L.

The influences of three exogenous organic acids(citric acid,oxalic acid and tartaric acid) on Cr tolerance,uptake and translocation by Canna indica L.were investigated based on nutrient solution-culture experiment.The results showed that addition of organic acids enhanced Canna indica L.resistance to Cr,increased the Cr uptake by Canna indica L.and the accumulation of Cr in the above-ground portion of the plant to some extent.However,various organic acids with different concentrations(4,8,16 mmol/L) caused different effects.Compared with citric acid and tartaric acid,oxalic acid at 16 mmol/L had a higher ability of Cr tolerance,especially as evidenced by significant increase in the level of roots growth and biomass of Canna indica L.The effects of organic acids on Canna indica L.to assimilate and transfer Cr to aboveground part were in the following decreasing order: citric acid>tartaric acid>oxalic acid,especially for citric acid at concentration of 16 mmol/L,while only tartaric acid and oxalic acid significantly increased Cr uptake by Canna indica L.and the accumulation of Cr in the above-ground portion of the plant at 8 mmol/L and 16 mmol/L,respectively.These results indicated that citric acid at 16 mmol/L was more suitable for phytoremediation of Cr wastewater.