I believe so. I don't see how a plant would be able to push these molecules out with the xylem alone. It would require a sort of filtration that separates hydro

I believe so. I don't see how a plant would be able to push these molecules out with the xylem alone. It would require a sort of filtration that separates hydrogen from oxygen and reforms them at the target site, and then deny all other molecules, which I don't believe is something we've seen in plant life.