Figure 4. Effect of nutrient level and social environment on soil hyphal length for juvenile A. artemisiifolia L plants.

Groups of four were solitary, siblings or strangers and all were inoculated with G. intraradices (n = 93). Solitary and sibling groups had high soil hyphal length in both high and low P, but strangers had low soil hyphal length in high P and increased soil hyphal length in low P (social environment × P level interaction P = 0.0338). Log fine root mass was the covariate and had no effect. White bars represent groups that received low P fertilizer, and black bars are groups in high P. Means that did not differ significantly at P<0.05 are represented by the same letter. Error bars represent ±1 s.e.m.