Abstract: The components with high allelopathic activity were separated fromTypha orientalis aqueous extract by liquidliquid partition and thinlayer chromatography. The components with high allelopathic activity were analyzed by gas chromatographmass spectrometry (GC/MS) toexamine the allelopathic effects of aqueous extract from different tissues ofT. orientalis onMicrocystis aeruginosa. The results showed that the inhibitory effects of different T. orientalis tissues were different, with the inhibitory effect of leaf extract > root extract > pollen extract. The inhibition rate of leaf extract onM. aeruginosa was up to 72.35%. The allelopathic effects of T. orientalis leaf aqueous extract onM. aeruginosa exhibited a phenomenon of inhibition at highconcentration (≥10 g·L^-1) while showed a trend of stimulation at low (≤5 g·L^-1). The allelopathic effects decreased the content of chlorophyll a, increased permeability of cellmembrane while initially increased then decreased SOD activity and MDA content. Results of GC-MS showed that the main allelochemicals from T. orientalis were phenolic acid, fatty acid, ester, ketone, amide, and so on. The results provide a theoretical guidance for the management ofaquatic ecosystems with algal blooms.

Key words: agricultural runoff, removal mechanism, pesticide, removal efficiency, influencing factor, constructed wetland