The Responses of Invasive Wedelia trilobata and Native Wedelia chinensis to Levofloxacin Hydrochloride: Implication for Biological Invasion

Invasion of alien plants has become a global problem, and antibiotics, a new pollutant, have received widespread attention. We hypothesized that different concentration levels of Levofloxacin hydrochloride facilitate different physiological, growth and antioxidant system responses in W. trilobata and W. chinensis. The toxicity of Levofloxacin hydrochloride was assessed in W. trilobata and W. chinensis through physiological, chlorophyll, and antioxidant system. Compared with single species, the two plants were more susceptible to the influence of levofloxacin hydrochloride when mixed; in sand culture, levofloxacin hydrochloride affected physiological parameters (leave size, number of leaves, plant height, stem length, and dry weight biomass). The exogenous addition of levofloxacin significantly restricted the root development of plants, especially in the case of hydroponics. Both plants showed prominent oxidative stress characteristics that leaves yellowed and withered, as well as showed on photosynthesis and antioxidant system. SOD presents different trends under different experiment units. CAT activity showed a significant decrease in all treatment groups. No significant difference observed in POD activity between both plants under sand culture conditions, and it increased after Levofloxacin hydrochloride application. Overall,our results revealed that invasive W. trilobata adapted well against Levofloxacin hydrochloride with better growth and antioxidant system, which strengthens the biological invasion process.