Fig. 4

Production of volatile compounds (β-ionone and β-cyclocitral) during the growth times of toxin-producing (LTPNA 08) and non-producing (LTPNA 01) strains of M. aeruginosa under different light intensities (LI). A LI 50 µmol photons m⁻² s⁻¹, B LI 150 µmol photons m⁻² s⁻¹, and C LI 250 µmol photons m⁻² s⁻¹ for β-ionone. D LI 50 µmol photons m⁻² s⁻¹, E LI 150 µmol photons m⁻² s⁻¹, and F LI 250 µmol photons m⁻² s⁻¹ for β-cyclocitral. Different letters represent significant differences over the growth time in each strain and LI (for β-ionone in LI 50 and LI 150, and β-cyclocitral in LI 50 and LI 250: Two Way Analysis of Variance followed by Tukey post-test, p < 0.05; for β-ionone in LI 250 and β-cyclocitral in LI 150: One Way Analysis of Variance followed by Tukey post-test, p < 0.05). * Represents a significant difference between the strains for each growth time (Student t-test or Mann–Whitney Rank Sum Test (at 18 days for β-cyclocitral in LI 150), p < 0.05)