Fig. 2

Foliar phytohormones in Arabidopsis grown at different levels of CO₂, nitrate fertilization and wounding stress. Plants were grown under ambient (440 ppm) or elevated (880 ppm) carbon dioxide (CO₂) levels and fertilized with either 1 mM or 10 mM nitrate (1 mM N or 10 mM N). At 6 weeks, Arabidopsis rosette leaves were mechanically damaged (mech. damaged, black bars) or untouched (control, white bars) and phytohormone levels analyzed. a Jasmonic acid (JA) b 7-Jasmonoyl-L-isoleucine (JA-Ile) c 12-oxo-phytodienoic acid (OPDA). Statistical differences were determined by 3-factor analysis of variance (Additional file 4: Table 3). When interactions were significant, data were separated to show treatment effects. Significant differences in response to wounding are denoted by alphabetical letters (p ≤ 0.05). An asterisk indicates significant differences between grouped variables