Toluidine Blue

[Nancy Harrison]

I need a recipe for this stain, to be used to stain
fresh plant tissue. I know several people have mentioned
it here - we don't have any at our lab, although we could
order it from Sigma. We're not sure whether to use the
alcohol solution or the aqueous solution. We'd rather
just get the raw materials and mix it ourselves.
We've had fun this past week with students being able
to "slice and dice" supermarket vegetables to look at
primary stem structure, but our stains leave a lot
to be desired! -NH

[Jose Feijo]

I would add that, as a general (non-specific) stain, TB works much better at
alkaline conditions (8.0 or even higher). Altough buffers can be used, we
generally make it in plain water, adjust pH, and it remains stable for a long
time (don't forget to seriously RINSE the pH electrode after adjustment;
people don't find it funny to get their solutions blue after you've been
there...). Regarding concentrations we have found very useful to have 3
concentrations around (0.01%, 0.1%, and 1.0%) to cope with the different
thickness and affinity of the material we're working with. While 1.0% is more
usefull to plastic embeded semi-thin sections (0.2-10 um) the two others cover
the range from 1 tp 30 um. Reaction hapens alomst imedaitely but having an hot
plate around helps reproducibility.
Hope it helps
Jose

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o o
o Professor Jose' A. Feijo' o
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o Dep. Biologia Vegetal, Fac.Ciencias Univ. Lisboa o
o Campo Grande, Ed.C2, P-1700 LISBOA, PORTUGAL o
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o tel. +351.1.7500069, fax +351.1.7500048 o
o e.mail: jose....@fc.ul.pt o
o URL: www.fc.ul.pt/departs/biologia_vegetal/ejf.html o
o o
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