What is the experiment/chemical called to test plant's life?

[crazylullaby]

Q: what is the experiment/chemical called/used to test life of plant root and stem? Part of root/stem will turn red if life presents. Thank you for the help. I am really stuck on the name of the experiment.

[JackBean]

do you mean dye to detect dead cells?

[crazylullaby]

Actually the plant root/stem is soaked in a specific chemical and is left for over night, and parts of plant root/stem will turn red, which indicates that part contains living cells. What is that experiment or chemical used called?

[crazylullaby]

That was the research I did to see the effective of herbicide on weeds. We collected the weed root samples with various condition and look at the amount of living cells that were presented in the roots. When living parts were detected, the parts would turn red. (Also what is the experiment/ chemical called to test the dead cells in the plant?)

[JackBean]

if you did it, then you should know the name, shouldn't you?
Or at least your advisor...

[crazylullaby]

It is called TTC test, testing viability. I did this experiment 4 years ago in my previous laboratory, and somehow I couldn't recall the name of the test the other day (blanked out). But thanks for the help.

[JackBean]

I see. What I meant was colouring with propidium iodide, which penetrates only dead cells and thus under microscope these are red.