Fig. 2

Visualization of Stipagrostis pungens rhizosheath with scanning electron microscopy (SEM). a Scanning electron microscope (SEM) image of a rhizosheath–root transverse section showing a dense matrix of root hairs (RH) and sand grains (asterisk, *) covering the central root cortex (c); separation between the epidermis and cortex (cortical lysis) is visible in Supplementary Fig. S2a. b–d Magnification of the rhizosheath matrix showing sand grains (asterisk, *) with intertwined root hairs (RH) and interstices, coated with mucilages (cryo-SEM panels b, c, and Supplementary Fig. S4a; SEM panel d, and Supplementary Fig. S4b) and flaky material on both sand grain and root hair surfaces (SEM in Supplementary Fig. S4c–i). e–h SEM images showing bacterial cells associated with the surface of roots, root hairs and sand grains (refer also to Supplementary Fig. S4). Note the different scales on the SEM micrographs; arrows with different colours indicate some of the different bacterial cells observed: black, lobed/warty surface; white, rods; orange, coccobacillus; #: EPS materials