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.