Staining callose-aniline blue

The medium for maceration (HC1 or NaOH) depends on the material and purpose of staining. If fresh material is at hand, NaOH is best. It keeps material at the proper pH even after washing a few times in water. It is very important to achieve a pH of 9.0-10.0 to obtain the proper fluorescence of callose after staining with aniline blue. 

Fig. 10. The deposition of callose in the plasmodesmata regions, suggesting the closure of plasmodesmata only between some of the explants cells (A), and in the cell wall, suggesting the isolation of neighbouring cells via apoplast (B) Arabidopsis explants during SE hand-cut sections stained with aniline blue bar = 15 pm).

Brundrett MC, Enstone DE, Peterson CA. A herherine-aniline blue fluorescent staining procedure for suberin, lignin and callose in plant tissues. Protoplasma 1988 146 133-142. 

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