Figure 3.

IAA concentrations in agar resulting from the exudation of truffle mycelia. After 10 d of growth in the dark, strains of T. borchii and T. melanosporum increased the IAA concentration from 3 to 10 times compared to the control petri dish containing no mycelium. IAA concentration after 10 more days in the growth chamber had dropped in all samples due to degradation by light (n = 3 or 4 petri dish/treatment, bars indicate sd; circles [○ for day 10 and • for day 10 + 10] indicate statistical differences compared to the respective controls, P < 0.05, Mann-Whitney).