Figure Legends
Fig.1: Stoichiometric responses in fungal C:N:P ratios to varying N and
P supply in defined glucose media. a, b and c depict
shifts in fungal C:N, C:P and N:P ratios in response to varying media
supply ratios (axes are log10 transformed). Lines represent the linear
response of fungal stoichiometry, symbols data points of individual
isolates (see legend). Line colors depict 1/H values calculated for each
fungal isolate, with maximum and minimum values shown in the respective
color legend.
Fig. 2: Fungal stoichiometric responses to nitrogen (N), phosphorus (P),
cellulose (Cel) and glucose (Glu) manipulations in soil extract agar.
Fungal C:N (a ), C:P (b ) and N:P (c ) values
are illustrated as violin plots, a mirrored density plot showing overall
data distribution, with average values illustrated by dots (8
(a ) or 4 (b,c ) isolates, 3 repetitions each). Letters
indicate deviations among treatments (linear mixed-effects model), red
dots deviations from control values (P < 0.05). Large
variations are mainly driven by distinct differences among isolates (see
Fig. S6).
Fig. 3: Correlations of total fungal (a ) carbon (C),
(b ) nitrogen (N) and (c ) phosphorus (P) mass [mg]
with fungal biomass [mg] in different nutrient manipulation
experiments (both standardized [0,1] for comparisons among elements
and fungal isolates). Lines show predicted model outputs from linear
mixed effects models, with grey areas illustrating 95% confidence
intervals. Line types indicate respective nutrient manipulation
experiments (solid: N manipulation in glucose medium; dashed: P
manipulation in glucose medium; dotdashed: N manipulation in cellulose
medium; longdashed: fertilization experiment in soil extract agar). For
correlations conducted in each medium respective formulas of regression
lines as well as R² values are given. Pie charts illustrate the relative
variation in element masses determined by fungal biomass (dark grey)
versus the respective nutrient manipulation treatments applied (light
blue). 3D correlation graphs (d-e ) further illustrate the
relative contribution of fungal biomass versus nutrient manipulation to
total element mass, exemplarily shown for N manipulations in defined
glucose media.
Fig. 4: Positive correlations of relative fungal nitrogen (N) and
phosphorus (P) concentrations [% deviation from maximum values] in
defined glucose media (a, d ), soil-extract agar (b,e )
and defined cellulose medium (c ). The relative deviation of
fungal concentrations of the manipulated element is depicted on the
x-axis, while the relative concentrations of the respective other
element (unchanged in media) is plotted on the y-axis. The chosen
relative values allow to assess effect sizes in element reductions, and
reduce isolate-specific variability by data standardization. Colors and
symbols depict respective treatments applied (see legends), black lines
predicted model outputs from linear mixed effects models, with grey
areas illustrating 95% confidence intervals (*** P <
0.001).
Fig. 5: Spatial and temporal shifts in fungal C:N ratios are depicted,
with colors illustrating fungal nitrogen concentrations (red: high,
grey: low). Stoichiometry was compared in (a ) inner versus
outer parts of the mycelium (4 fungal isolates, 3 repetitions each), and
in fungi grown for 12 or 26 days (b ) on soil-extract agar (12
fungal isolates, 3 repetitions each), as well as in (c ) inner
versus outer parts of mycelium grown in glucose media with low (C:N =
200) and high (C:N = 20) N supply (4 fungal isolates, 3 repetitions
each). (a, b ) Dots represent data points underlain by
box-and-whisker plots. P -values are based on paired t-tests.
Illustrations depict potential element distributions in fungal mycelia
(see Fig. 6). (c ) Bars illustrate mean values of fungal C:N
ratios measured in inner (hatched bars) and outer (filled bars) parts of
the fungal mycelium. Tested fungal isolates differ in
1/HCN values, previously determined along a larger
gradient of C:N (see Fig. 1). Given P -values are based on
three-way type III analyses of variances.
Fig. 6: Illustration of potential mechanisms in fungal mycelia allowing
flexible carbon:nutrient (C:X) adjustments to nutrient limited
conditions. Colors indicate element contents throughout different
mycelial parts (red: low C:X, i.e. high nutrient contents; grey: wide
C:X, i.e. low nutrient contents). Little grey dots illustrate the
distribution of C throughout mycelia, red dots nutrients, e.g. nitrogen
and phosphorus. Mycelial growth form depicts typical adaptations to
reduced nutrient supply (decreased biomass, density and activity (Fig.
S2; Camenzind et al. 2020)).