Fig. 4

Evaluation of individual VOCs produced by B. subtilis SYST2 for plant growth promotion. Tobacco seedlings were exposed to the specific individual VOCs albuterol and 1,3-propanediol dissolved in DMSO at four different concentrations in pots as described above for 28 days at 28/22 °C day/night under 16/8-h light/dark photoperiod. Plant fresh weights (a), dry weights (b), leaf area (c) and photosynthesis rate (d) were determined. Error bars indicate the standard deviation from the mean. Letters above the columns indicate a significant difference at P < 0.05. Experiments were replicated three times