Effects and mechanisms of aquatic landscape plants on the removal of veterinary antibiotics from hydroponic solutions

Four aquatic landscape plants and three veterinary antibiotics were selected to construct a hydroponic test system to analyze the tolerance, removal effect and mechanism of antibiotics. The results indicated that antibiotic concentrations from 0 to 100 μg·L^-1 promoted plant heights and leaf chlorophyll contents, while antibiotics at concentrations > 100 μg·L^-1 had inhibitory effects. The ability of different plants to remove antibiotics was <i>Acorus calamus</i> L. > <i>Ceratophyllum demersum</i> L. > <i>Thalia dealbata</i> Fraser > <i>Nuphar pumila</i> (Timm) DC. The plants with the best removal of norfloxacin, sulfadimethoxine and chlortetracycline were <i>Ceratophyllum demersum</i> L., <i>Acorus calamus</i> L. and <i>Acorus calamus</i> L. after 12 d of hydroponic cultivation using 100 μg·L^-1 antibiotics, with removal rates of 66.6%, 63.0% and 63.2%, respectively. The accumulation of antibiotics in different plant tissues was root > stem > leaf and the accumulation increased with incubation time. The diversity of plant root biofilm microorganisms decreased with increasing treatment concentrations of antibiotics, while the abundance of dominant genera (<i>Aeromonas</i>, <i>Bacillus</i>, <i>Lysinibacillus</i>, <i>Providencia</i>, and <i>Staphylococcus</i>) showed an increasing trend. The findings imply that the antibiotic uptake by plants and the dynamics of the rhizosphere microbial community combine to promote antibiotic removal.