Physiological response and pollutant removal efficiency of pontederia cordata to urban polluted river water under aeration condition

To analyze the changes in the physiological responses and pollutant removal efficiencies of Pontederia cordata under long-term continuous aeration conditions during three seasons (spring, summer and autumn), P. cordata was hydroponically cultivated for 9 months in six purifying tanks (aeration, non-aeration) to treat urban polluted river water. The results indicated that aeration significantly influenced the morphological characteristics and physiological responses of P. cordata and water purification. The roots, stems and leaves of P. cordata grown under aeration conditions were shorter than those of plants grown under nonaeration conditions. The biomass and accumulation of nitrogen and phosphorous by P. cordata under aeration conditions were lower than those of plants grown under nonaeration conditions. Aeration resulted in the densities of the tillers and roots increasing. In addition, aeration led to increased activities of peroxidase (POD) and catalase (CAT) and decreased contents of chlorophyll (Chla, ChIb) and soluble protein (SP). In the aeration purifying tanks, the average removal efficiencies of chemical oxygen demand (CODcr), total nitrogen (TN) and ammonia nitrogen (NH ₄ ⁺N) increased by 16.67%, 12.13% and 14.16%, respectively, during all three seasons, while the average removal efficiencies of total phosphorus (TP) and total dissolved phosphorus (TDP) decreased by 10.47% and 9.74%, respectively.