I'd say it does a little of both, just as our bodies can rehydrate somewhat from the shower or tub..
A couple of friends of mine who were closely associated with Father Wilhelm before he passed away used to place tired veggies in a bowl of water with a little Food-grade Hydrogen Peroxide in the water, and then place the bowl in the fridge.
They swore it rejuvenated the veggies in a miraculous fashion, and kept them looking well for far longer, too.
I have not done this, as they used to purchase their H2O2 (Hydrogen-Peroxid) by the gallon wholesale, and I do not. I do plan to try it someday though..