Plants Mitigate Nitrous Oxide Emissions from Antibiotic-Contaminated Agricultural Soils

Vegetableproductionsystemsarehotspotsofnitrous oxide (N2O) emissions and antibiotic pollution. However,little is known about the interconnections among N2O emissions,vegetable growth, and antibiotic contamination. To understandhow plants regulate N2O emissions from enrofloxacin (ENR)-contaminated soils, in situ N2O emissions were measured in potexperiments with cherry radish and pakchoi. Gross N2Oproduction and consumption processes were discriminated basedon an acetylene inhibition experiment. Results indicated thatvegetable growth decreased the cumulative N2Oflux from 0.71 to-0.29 kg ha-1and mitigated the ENR-induced increase in N2Oemissions. Radish displayed better mitigation of N2O emissionsthan pakchoi. By combining the analysis of N2Oflux with soilphysicochemical and microbiological properties, we demonstrated that growing vegetables could either promote gross N2Oconsumption or decrease gross N2O production, primarily by interacting with soil nitrate, clade IInosZ(nosZII)-carrying bacteria,andDeinococcus-Thermus. ENR inhibited N2O consumption more than N2O production, with thenosZII-carrying bacteria,represented byGemmatimonadetes, as the main inhibition target. However, increasingnosZII-carrying bacteria by growing radishoffsets the inhibitory effect of ENR. Thesefindings provide new insights into N2O emissions and antibiotic pollution in vegetable-soil ecosystems and broaden the options for mitigating N2O emissions.