Figure 4.

NOx effect on kinetics of O₂ and N₂O depletion. O₂ and N₂O consumption, and NO and N₂ production by E. meliloti 1021 (A,B), and napA (C) and nirK (D) mutant strains when incubated in the presence of 1% O₂ plus 2% N₂O in the headspace. Cells were incubated in minimal medium with (A,C,D) or without (B) 10 mM NO⁻₃. Cultures with an initial OD₆₀₀of 0.01 were vigorously stirred at 700 rpm. Plotted values are average of three replicate flasks for each treatment, with standard deviation (SD) as vertical bars (n = 3).