An evaluation for the medium-term storage and viability of root cortex tissues stained with blue ink in the assessment of arbuscular mycorrhizal fungi

Abstract

Sheaffer blue ink is an effective method to stain arbuscular mycorrhizal (AM) fungi in a variety of plant species. It has, however, received criticism for its potential rapid degradation and short-term viability. The long and medium term storage and viability of stained samples has not, to date, been described for this particular staining method. This short communication reports on the viability of 730 samples stained with Sheaffer blue ink stored for the duration of 4 years in microscope slide boxes out of direct sunlight. There was no significant difference in micrograph image quality and presence of stain between years as indicated by the number of AM fungal structures quantified. In conclusion Sheaffer blue ink stain does not deteriorate in the medium term.

Alternative inks for arbuscular mycorrhizal root staining

“…It is worth noting that the interpretation of Sheaffer blue-stained root tissues has been mistakenly assumed to be stained plant cell components [ 9 ]. As shown by Wilkes [ 8 ] and Wilkes and Warner [ 10 ], Sheaffer blue was not able to stain any cellular components in wheat samples grown under aseptic conditions, i.e. in the absence of AM fungi.…”