Figure 4.

The degree of VOC-mediated plant growth promotion in Arabidopsis depends on the Serendipita culture medium. (A) Arabidopsis plant growth (on ½ MS without sucrose) after 10 days of co-cultivation with Serendipita isolate 30, grown on different nutrient sources in the right compartment of I‐plates: 1. ½ MS + 1% sucrose (control plate), 2. plant nutrition medium (PNM), 3. ½ MS without sucrose, 4. ½ MS + 1% sucrose, 5. malt yeast peptone (MYP), 6. malt extract agar (MEA), 7. complex medium (CM), 8. potato dextrose agar (PDA). Plates 2–8 are inoculated with Serendipita whereas plate 1 is not. (B) Leaf series of a representative plant from each of the different growth conditions as presented in (A). (C) Plant growth effects caused by a 10-day exposure to Serendipita volatiles in a Petri-dish-in-box assay using isolate 30 grown on PDA and on ½ MS medium with 0%, 1% and 3% sucrose. (D) Mean shoot fresh weight of plants from (C). (E) Pixel distribution across five F_v/F_m classes based on chlorophyll fluorescence imaging of plant shoots from the Petri-dish-in-box assay (C). Average total values of F_v/F_m for each of the tested fungal media are shown above the respective stacked bars (standard errors are very low, ≤ 0.02). The results of the spectral measurements of anthocyanin and chlorophyll content are included in Supplementary Figure S11. Error bars in (D, E) indicate standard errors on the mean of four biological replicates; treatments sharing the same letter do not show statistically significant differences according to Tukey HSD post hoc tests (α = 0.05). Con, Control; MS, ½ Murashige and Skoog medium; Suc, Sucrose; PDA, potato dextrose agar. Scale bars = 1 cm.