Physiological responses and nitrogen and phosphorus removals variations of Pontederia cordata under long period aeration

Pontederia cordata was hydroponic cultivated in 6 purifying-tanks (with and without aeration) with same planting density of 10, to investigate physiological traits of the plants and the main physical and chemical traits of the effluents. Effects of aeration on physiological traits of the plants and purifying efficiencies of the purifying-tanks during treatment for heavily polluted water were comparatively analyzed, another tank without plant for control (CK). Results showed aeration affected physiological traits of the plants. Roots, stems and leaves lengths of the plants at aeration were shorter than the non aeration. Chla, Chlb and SP contents of leaves were lower than the non aeration by decreasing 0.1877 mg/g, 0.0847 mg/g and 17.36 mg/g. While POD and CAT activities of roots tissues at aeration exceeded the non aeration by 0.0146 U/(g · min) and 0.3095 mg/(g · min). N and P accumulation and biomass of the plants were higher at non aeration than the aeration by increasing 0.87 g/kg, 0.35 g/kg and 2.13 g/plant. Tillers and roots densities at aeration were more than the non aeration. COD and NH₄⁺-N removals of the effluents at aeration exceeded the non aeration by 12.73% and 8.31%, while soluble P removals were lower by declining 24.86%.