AM fungal inoculum as a single factor was significant (P < 0.001) with distinct species combinations resulting in different levels of root colonisation. The individual inocula resulted in similar levels of colonisation (9.9%–16.2%; LSD = 7.01) irrespective of species, therefore valid comparisons with and between the mixed species could be made. The highest percentage colonisation was observed in the two-species mixture of G. geosporum plus G. mosseae (25.4%), followed by the combination of all three species (23.8%). Percentage colonisation by G. geosporum plus G. mosseae in combination appeared to be additive relative to that observed by the species individually (16.2%, G. geosporum; 9.9% G. mosseae). Colonisation was markedly reduced when G. mosseae and G. intraradices were paired (7.5%), particularly compared to the performance of G. intraradices individually (14.2%). Arbuscules followed a similar pattern to hyphal colonisation, with the G. geosporum and G. mosseae combination containing the most arbuscules (data not shown). No mycorrhizal colonisation was observed in the uninoculated plant roots.
AM fungal inoculum as a single factor
P
< 0.001
levels of colonisation
9.9%–16.2%
%
levels of colonisation
LSD
7.01
two-species mixture of G. geosporum plus G. mosseae
percentage colonisation
25.4%
%
combination of all three species
percentage colonisation
23.8%
%
G. geosporum
Percentage colonisation
16.2%
%
G. mosseae
Percentage colonisation
9.9%
%
G. mosseae and G. intraradices
Colonisation
7.5%
%
G. intraradices
Colonisation
14.2%
%