Radial Oxygen Loss of Three Plants under Hydroponic Culture and Its Relationships with Pollution Removal

Abstract

The growth status, root exudates, radial oxygen loss, and sewage purification effect of plants acclimated with sewage and cultured with a nutrient solution were studied by selecting Acorus gramineus Aiton, Pistia stratiotes L., and Eichhornia crassipes (Mart.) Solms with the same individual size. The results showed that the root oxygen secretion rate of the Acorus gramineus Aiton was higher in light and dark conditions. For a single plant species, the oxygen secretion rate under light conditions was much higher than that under dark conditions. The root oxygen secretion rate of Acorus gramineus Aiton was the highest (2.03 µmol O2/h/plant), followed by Pistia stratiotes L. (1.68 µmol O2/h/plant), and the root oxygen secretion rate of Eichhornia crassipes (Mart.) Solms was the lowest (1.15 µmol O2/h/plant). After a period of adaptation, plants showed strong removal effects on COD, NH3-N, TN, and TP. The removal intensity was in the order of Acorus gramineus Aiton > Pistia stratiotes L. > Eichhornia crassipes (Mart.) Solms; the higher the temperature, the bigger the removal rate. These results were consistent with Acorus gramineus Aiton‘s organic matter secretion and radial oxygen loss, which were better than those of Pistia stratiotes L. and Eichhornia crassipes (Mart.) Solms. Three kinds of plants had better COD removal effects in an acidic environment and better TP removal effects in an alkaline environment. The results show that using the Acorus gramineus Aiton can achieve better remediation of polluted water bodies.