Plants monitor the integrity of their barrier by sensing gas diffusion

At what point will we see that plants are conscious, just in a different manner than animals colloquially?

Stimulus-response is not consciousness. There is nothing subjective about this mechanical and chemical response to injury.

Science hasn't really understood consciousness.

If you don't understand consciousness, how to make it from first principles and how it works, then I don't think you can confidently say "this isn't conscious" about much.

We can explain plant behavior through known physical processes though.

We don't need to lean on consciousness nor other mysteries at all. Nor we do have to when a rock changes color as it gets wet.

And without this parsimony, then we could claim that any unexplained mystery underlies any well-understood phenomenon which doesn't sound like much of an epistemic standard.

You could just as well make the same argument about human behavior in a broad perspective. Not understanding every minute interaction in our brain is a fairly secondary point when the overarching themes are all the same.