You see a slowing in growth and eventual plant death. Typically you see a darkening around the roots of the plant or stem in the agar.
This happens most often with stem propagation and sometimes in seedlings. The answer is reflasking. You may have to reflask several times until the plant stops exuding phenols into the agar.
Thay I cant tell you. No idea. All I know is that some stem propagations and to a lesser extent seedlings exude phenols. Certain agar may promote it. I was told you can try reflasking in half strength agar and not to use banana in it. Coconut maybe an ok subsitute. Also, reduce the amount of light the flask is getting.
However, the thing you will have to do is keep reflasking until it the plant stops doing it. It may take 5 or 6 reflasks even.
Sorry, cant help more on this. Maybe someone else can chime in with some information on why.
I think it is just a simple wound response. Brett is certainly right that replating into fresh media is the only real solution. Eventually the explant will stop "bleeding" and normal growth takes over.
This is interesting! Did the phenol poisoning turn the agar amber in the first flask? Is banana common in agar? Hard to believe one stem could make such a change!
This is the first stem flask I (newbie) have seen! Thanks for showing us!
The build-up of phenolic compounds slowly darken the media, eventually it will turn brown/black.
Agar is just one component of media for solidification. Banana is common, especially in replate formulas, and acts as a source of sugar. It is not really that common for stem props, though.