Supplementary material

Preparation of AM inoculum for experiment from cultures obtained from INVAM and BEG

Pure cultures of AM fungi (approximately 50g fresh weight roots/spores/hyphae/growth medium) were mixed with approximately 1 kg of a 50:50 by weight, sterile sand/Terra-Green mixture and added to 1 litre pots. Pre germinated Plantagolancellota seeds were added to the pots and pots placed into Sunbags (Walker and Vestberg 1994). Pots were placed in a controlled environment cabinet 20oC for 8 months for plants to grow and AM fungi to multiply. At the end of this period pot cultures were examined to confirm colonisation of plant roots and presence of AM spores. All AM species had sporulated. Pot cultures were harvested and plant tops were removed. Roots were chopped to < 2cm lengths and thoroughly mixed through the sand/ Terra-Green substrate, this mixed substrate was used as inoculum and was stored at 4oC until use.

Walker C, Vestberg M (1994) A simple and inexpensive method for producing and maintaining closed pot cultures of arbuscularmycorrhizal fungi. AgrSciFinland 32: 33-240

Table S1 Number of replicates of each AM fungal diversity treatment (number of species added to a pot ignoring identity of species).

Total number of fungi present / Number of replicates
0 / 3
1 / 7
2 / 21
3 / 35
4 / 35
5 / 21
6 / 7
7 / 3

Table S2 Shoot dry weight, results of ANOVA

Source of variation / d.f. / s.s. / m.s. / Variance ratio / F pr.
Control / 2 / 1.66 / 1.66 / 5.10 / 0.009
R.manihotis / 1 / 0.49 / 0.49 / 3.04 / 0.086
A. spinosa / 1 / 0.19 / 0.19 / 1.17 / 0.283
F. caledonium / 1 / 1.02 / 1.02 / 6.24 / 0.015
P. occultum / 1 / 0.12 / 0.12 / 0.72 / 0.398
F.mosseae / 1 / 2.28 / 2.28 / 14.01 / <0.001
R. fulgida / 1 / 0.31 / 0.31 / 1.88 / 0.175
R. irregularis / 1 / 2.39 / 2.39 / 14.69 / <0.001
Residual / 64 / 10.41 / 0.16
Total / 131 / 34.94

Table S3 Shoot phosphorus concentration, results of ANOVA

Source of variation / d.f. / s.s. / m.s. / Variance ratio / F pr.
Control / 2 / 0.072 / 0.036 / 19.22 / <0.001
R.manihotis / 1 / <0.001 / <0.001 / 0.18 / 0.675
A. spinosa / 1 / 0.040 / 0.040 / 21.44 / <0.001
F. caledonium / 1 / 0.092 / 0.092 / 49.10 / <0.001
P. occultum / 1 / 0.007 / 0.007 / 4.13 / 0.046
F.mosseae / 1 / <0.001 / <0.001 / 0.36 / 0.548
R. fulgida / 1 / <0.001 / <0.001 / 0.10 / 0.754
R. irregularis / 1 / 0.003 / 0.003 / 1.53 / 0.221
Residual / 64 / 0.119 / 0.002
Total / 131 / 0.464

Table S4 Shoot copper concentration, results of ANOVA

Source of variation / d.f. / s.s. / m.s. / Variance ratio / F pr.
Control / 2 / 8.302 / 4.151 / 3.39 / 0.040
R.manihotis / 1 / <0.001 / <0.001 / <0.001 / 0.993
A. spinosa / 1 / 1.119 / 1.119 / 0.91 / 0.343
F. caledonium / 1 / 11.485 / 11.485 / 9.12 / 0.004
P. occultum / 1 / 0.058 / 0.058 / 0.05 / 0.829
F.mosseae / 1 / 3.556 / 3.556 / 2.90 / 0.093
R. fulgida / 1 / 0.988 / 0.988 / 0.81 / 0.373
R. irregularis / 1 / 1.945 / 1.945 / 1.59 / 0.212
Residual / 64 / 78.46 / 1.226
Total / 131 / 188.27

Table S5 Shoot potassium concentration, results of ANOVA

Source of variation / d.f. / s.s. / m.s. / Variance ratio / F pr.
Control / 2 / 1.097 / 0.549 / 3.37 / 0.041
R.manihotis / 1 / 0.014 / 0.014 / 0.08 / 0.773
A. spinosa / 1 / 0.450 / 0.450 / 2.77 / 0.101
F. caledonium / 1 / 0.472 / 0.472 / 2.90 / 0.093
P. occultum / 1 / 0.020 / 0.020 / 0.12 / 0.725
F.mosseae / 1 / 1.954 / 1.954 / 12.01 / <0.001
R. fulgida / 1 / 0.146 / 0.146 / 0.90 / 0.348
R. irregularis / 1 / 1.227 / 1.227 / 7.54 / 0.008
Residual / 64 / 10.413 / 0.163
Total / 131 / 33.541

Table S6 Shoot sulphur concentration, results of ANOVA

Source of variation / d.f. / s.s. / m.s. / Variance ratio / F pr.
Control / 2 / 0.0011 / 0.0006 / 1.15 / 0.323
R.manihotis / 1 / 0.0015 / 0.0015 / 3.16 / 0.080
A. spinosa / 1 / 0.0005 / 0.0005 / 1.05 / 0.309
F. caledonium / 1 / 0.0017 / 0.0017 / 3.67 / 0.060
P. occultum / 1 / <0.0001 / <0.0001 / 0.01 / 0.939
F.mosseae / 1 / 0.0014 / 0.0014 / 2.95 / 0.091
R. fulgida / 1 / 0.0006 / 0.0006 / 1.32 / 0.255
R. irregularis / 1 / 0.0041 / 0.0041 / 8.55 / 0.005
Residual / 64 / 0.0309 / 0.0005
Total / 131 / 0.0940

Table S7 Summary of effects of tested AM fungi on growth and nutrient uptake in onion. Blanks indicate no statistically significant effect (singly or in mixtures). + and – indicate a significant positive or negative effect of the fungus

AM Fungi / Growth / N / P / K / Mg / Ca / S / Cu / Fe
R. manihotis
R.irregularis / + / - / -
F.caledonium / + / + / +
F. mosseae / + / - / -
A. spinosa / +
P. occultum / +
R. fulgida