In pure cultures of fungal isolates, the ergosterol concentration varied from 1.1 ± 0.1 to 5.2 ± 1.2 g mg−1 of mycelium fresh weight as reported in Table 1. The conversion factor of ergosterol into mycelium fresh weight was calculated using the mean and was 2.38 ± 0.7 g of ergosterol mg−1 of mycelium fresh weight. Full data for ergosterol content in plant roots and conversion into relative fresh mycelium biomass using the conversion factor are presented in ESM Table 3. Summarized values of
fresh mycelium biomass in the root system are presented in Fig. 3:in A. spirorbis the mycelial biomass attributable to ECM was from 2.61 ± 0.06% to 6.71 ± 1.35% and in E. globulus the mycelial biomass attributable to ECM was from 1.22 ± 0.57% to 2.77 ± 0.76%.