Enhanced nitrogen deposition exacerbates the negative effect of increasing background ozone in Dactylis glomerata, but not Ranunculus acris

► Dactylis glomerata and Ranunculus acris enhanced senescence with increasing O3. ► Ozone effects on root biomass were larger than on shoot biomass in both species. ► N deposition exacerbated the negative O3 effect on D. glomerata root biomass. ► Inter-specific differences in the response to O3 and N combined exposure.