FIGURE 5.

Arabidopsis thaliana growth stimulation by different amounts of individual volatile compounds emitted by P. phytofirmans PsJN. Root growth (A) and fresh weight (B) were determined for A. thaliana col-0 grown in vitro MS¹/₂ agar medium without bacterial inoculum, and in the presence of different amounts of volatile compounds added per plate. Tested compounds were 2-undecanone (2-UN); 1-heptanol (1-HP); 3-methyl-butanol (3-MB); or dimethyl disulphide (DMDS) at the indicated amounts. Growth parameters were registered at 21 DAS. Columns show mean values, and the error bars indicate standard deviations from experiments with 24 plants analyzed for each compound concentration. Asterisks indicate statistically significant differences from the control (N. I.) treatment within each compound (One way ANOVA Tukey’s HSD tests; p < 0.05).