Figure 2.

A, Representative ¹H NMR difference spectrum for elevated minus standard O₂ conditions. NMR spectra of soluble metabolite extracts of cells grown for 5 d under standard O₂ conditions were subtracted from the corresponding spectra for cells grown under elevated O₂ conditions. Metabolites giving positive signals in this difference spectrum are more abundant under elevated O₂ conditions. B, The abundance of soluble metabolites in Arabidopsis cell suspension cells after 4.5 to 5.5 d incubation under standard (○) or elevated (•) O₂ conditions. Errors are ±1 sd (n = 2 or 3). “a” indicates statistically significant differences (Student's t test, P < 0.05) in metabolite abundances between the two conditions for that time point. “b” indicates statistically significant differences (Student's t test, P < 0.05) in metabolite abundance under a particular condition between the indicated time point and 4.5 d growth. No significant differences in abundance were detected between 5 and 5.5 d growth.