At 04:55 PM 2/7/2007, you wrote:
>Toluidine blue also works for lignified and suberized tissues, and it's
>safer than phloroglucinol. I have never mixed it up, so I don't know
>the recipe, but I've seen references to 0.1% and 0.05%.
I got a recipe from Sue Schenk years ago that calls for 0.2% in
distilled water. It works pretty well, though lightly lignified
thickenings do not stain a particularly dark blue green (in contrast
to the blue-purple of unlignified cell walls), which may not be
surprising. I also tried a buffered formulation that I got from some
other source and it was more of a pain to mix and seemed to give no
better results.
I have seen the damage to stages and objectives due to proximity to
the HCl in the standard phloroglucinol formulation and it is not pretty.
Wil Taylor
