The effect of 1 mmol/L exogenous spermidine on remediation of heavy metal polluted municipal sludges with Phytolacca americana L.,was investigated in this paper.The results showed that the root growth and biomass of P.americana L.increased by more than 1.5 times under exogenous spermidine treatments.In addition,the contents of chlorophyll a and total chlorophyll increased significantly,and the loss of chlorophyll reduced.The absorption of Cd and Hg of municipal sludges and their transport and enrichment in ...