银叶树对重金属污染湿地环境的适应性和修复潜力

[Objective]The aim of this study was to investigate the growth adaptability and remediation potential of Heritiera littoralis to heavy metal pollution,and to provide a reference basis for phytoremediation in wetlands.[Method]H.littoralis was studied in a simulated wetland environment under potted conditions,with no added heavy metals as control(CK),to investigate the effects of T1(adding Pb 50 mg·L-1,Cd 5 mg·L-1,Cu 100 mg·L-1),T2(adding Pb 100 mg·L-1,Cd 10 mg·L-1,Cu 200 mg·L-1)and T3(adding Pb 200 mg·L-1,Cd 20 mg·L-1,Cu 400 mg·L-1)on the growth,nutrient uptake,and Pb,Cd,and Cu accumulation of H.littoralis,in order to analyze the remediation potential of H.littoralis for heavy metal polluted wetland environments.[Results]The root biomass of H.littoralis was not different from T1 compared with CK,but significantly inhibited under T2 and T3,besides,the plant height,aboveground biomass and total biomass of H.littoralis were not different from CK under all three treatments.The tolerance index was 103.96%under T1,but decreased to 95.18%and 80.80%under T2 and T3,while the N,P and K uptake by H.littoralis was not affected under T1,T2 and T3.With the increase of heavy metal concentration,the accumulation of Pb,Cd and Cu uptake by H.littoralis increased continuously,and most of them were stored in the roots.The transfer factor of Pb and Cu decreased significantly under three treatments compared with CK,while the transfer factor of Cd showed a trend of first increase and then decrease.The results of the entropy-weighted TOPSIS model showed that H.littoralis had the highest remediation potential under T3,followed by T2 and T1.[Conclusion]H.littoralis is well adapted to grow in heavy metal polluted wetlands,but excessive heavy metal concentrations significantly inhibit root growth.In Pb content≤50 mg·L-1,Cd content≤5 mg·L-1 and Cu content≤100 mg·L-1,the growth of H.littoralis was not affected,with a certain potential to remediate heavy metal pollution.