Figures 9 and 10 in More than meets the eye: regional specialisation and microbial cover of the blade of Porphyra umbilicalis (Bangiophyceae, Rhodophyta)

Figures 9 and 10: Holdfast structure. (9) TEM of rhizoid cells in holdfast. The holdfast is a thick, flexible structure made of polysaccharide secreted by the pear-shaped rhizoid cells. Note the large amount of floridean starch (arrows) in the pear-shaped end of the rhizoid cell where the large plastid and its pyrenoid are evident. (10) Toluidine blue O-stained holdfast section. The polysaccharide that is secreted includes a thick, metachromatic pad at the base of the holdfast, and the cell walls of rhizoid cells are also metachromatic (arrows). Holdfasts from blades collected at Schoodic Point (ME) in November 2009 were fixed in 2% glutaraldehyde in seawater for 2 h, post-fixed in 4% OsO4, dehydrated in a standard series of ethanol and propylene oxide and embedded in Epon. Holdfasts from additional blades fixed as above were embedded in Spurr's resin (EM Sciences) and semithin sections stained with toluidine blue O (TBO) per Brawley and Quatrano (1979).