[Plant-education] stain vascular tissue?

[Wilson A. Taylor]

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