Fig. 1.

a–e Tall fescue seedlings stained with DAB. a Fescue seedlings on agarose showing H₂O₂ secretion (red coloration) from roots; b and c Fescue root hair showing bacterial cells staining brown due to H₂O₂ concentration (arrows); d Fescue root hair showing bacterial cells losing rod structure and capacity to stain with aniline blue during oxidation (arrows; stained with DAB/peroxidase, then counterstained with 0.1 % aniline blue; e Seedling mesocotyl showing brown areas (arrows) that mark sites of bacterial oxidation