The Enrichment Characteristics Of U, Cd, As And Pb In Alisma And Herba Houttuyniae Studied

In order to effectively use wet plants to treat uranium and associated heavy metals contaminated water and the environment,one of the key technologies of biological purification is to screen wet enriched plants.Such as Alisma,Herba Houttuynia,Mentha haplocalyx and Duchesnea indica（Andr.）Focke,Alisma and Herba Houttuynia has a greater accumulation of uranium,and the enrichment rules of U,Cd,As and Pb in water under single pollution were studied.The research results are as follows:With the increase of U（0,5,30,55 mg/L）concentration,the biological growth,soluble protein content,maximum photochemical efficiency（Fv/Fm）of Alisma orientalis gradually decreased;and the corresponding indicators of Herba Houttuynia It showed a trend of increasing first and then decreasing;the antioxidant enzyme activities and photosynthetic performance index of Alisma and Herba Houttuynia increased first and then decreased;the content of Mentha haplocalyx and the concentration of enrichment for uranium gradually increased.The maximum enrichment concentrations of uranium in the stems and leaves of Alisma and Herba Houttuynia were 2787.74 mg/kg and 3184.91 mg/kg,respectively,and the maximum enrichment concentrations of uranium in the roots were 10393.94 mg/kg and 6515.00 mg/kg.The hygrophyte alternative plants mint and Duchesnea indica（Andr.）Focke show similar plant-enriching characteristics as Herba Houttuynia,and the enrichment advantages of uranium from large to small are:Alisma>Herba Houttuynia>Mentha haplocalyx>Duchesnea indica（Andr.）Focke.As Cd（0,1,4,8 mg/L）,As（0,1,2,4 mg/L）and Pb（0,5,30,55 mg/L）treatment concentrations increased,The Alisma enrichment concentration gradually increased.The maximum enrichment concentration of stem and leaf was Cd（2285mg/kg）,As（10985mg/kg）and Pb（136925 mg/kg）,respectively,and the maximum enrichment concentration of root was Cd（2690mg/kg）.As（9260mg/kg）and Pb（51215mg/kg）;the biotransport coefficient of Alisma to As and Pb and the intercellular CO₂ concentration of leaves gradually increase;the enrichment factor（BCF）of Alisma and maximum photochemical efficiency The biotransport coefficient（TF）of Cd showed a trend of increasing first and then decreasing.With the increase of Cd,As and Pb treatment concentrations,the stomatal conductance of the leaves of Alisma gradually decreased,and the transpiration rate of its leaves first After falling.With increasing concentrations of Cd（0,1,4,8 mg/L）,As（0,1,2,4 mg/L）and Pb（0,5,30,55 mg/L）,Herba Houttuynia The enrichment concentration gradually increased,the maximum enrichment concentration of stems and leaves were 1805mg/kg,1245mg/kg and37410mg/kg,the maximum enrichment concentration of roots were 2985mg/kg,4650mg/kg and 70440mg/kg;Herba Houttuynia to As and Pb biotransport coefficient（TF）,leaf intercellular CO₂ concentration and Cd treatment photosynthetic performance index of Herba Houttuynia increased gradually,Herba Houttuynia enrichment coefficient,maximum photochemical efficiency（Fv/Fm）,the biotransport coefficient under Cd treatment and the photosynthetic performance index(PI_ABS)under As and Pb treatments all showed a trend of rising first and then falling.The transpiration rate of Herba Houttuynia first fell and then increased.The rates are gradually decreasing.Under compound pollution,Alisma has a significant effect on U（r=0.6083**）,Cd（r=0.6067**）,As（r=0.6004**）and Pb（r=0.6470**）and U and The concentrations of Cd,As,and Pb were significantly positively correlated.Herba Houttuynia showed U（r=0.5223**）,Cd（r=0.7009**）,As（r=0.7003**）and Pb（r=0.6400**）Is significantly positively correlated;As has a significant positive effect on the enrichment of Alisma Cd（r=0.5630**）.Cd had a significant negative effect on the enrichment of Alisma U（r=-4085*）and Pb（r=-0.3609*）;Pb had a significantly positive enrichment of Herba Houttuynia As（r=-0.4504*）Effect,U has a significant negative effect on the concentration of Pb（r=-0.4521*）Herba Houttuynia,As has a significant negative effect on the concentration of Pb（r=-0.4784*）Herba Houttuynia.