Enhancing aniline blue fluorescent staining of cell wall structures.

Prior staining with the periodic acid-Schiff reaction, toluidine blue O, Congo red, or Calcofluor White M2R New, or reduction by NaBH4 do not interfere with aniline blue-induced fluorescence of sieve plates, new cell walls, pit fields or tracheids in compression wood of conifers. Detail of such fluorescent structures is improved by these treatments because of increased contrast, reduced flare, and a quenching of autofluorescence.