Vesicular-arbuscular mycorrhizal fungi colonization in Capsella bursa-pastoris (Brassicaceae)

Capsella bursa-pastoris (L.) Medikus (Brassicaceae) was sampled in lawn and waste habitats from three Ohio sites in April, May, June and July 1992. Vesicular-arbuscular mycorrhizal (VAM) fungi colonization was determined for 30 individuals per date/site/habitat by examining root subsamples for the presence of internal fungal structures. The mean percent colonization of VAM fungi in lawn habitats (35%) was over twice that in waste habitats (15%). This suggests that the dense mycorrhizal matrix offered by the lawn habitat influences the development of VAM in this typically nonmycorrhizal species. No arbuscules were observed in the 7200 root segments examined; however, internal hyphae, vesicles and chlamydospores were common. These results suggest that the surrounding community's root matrix can influence colonization of VAM fungi in roots of typically nonmycorrhizal plants.