Jim, I recently saw something that sounded like it might explain why dilute hydrogen peroxide helps some seeds germinate.
I was trying to find out what "ROS" meant, and found "Reactive oxygen species". It seems to be a current topic of research, but based on titles of papers, these "Reactive oxygen" compounds serve plants (or seeds, or seedlings) as "signalling" compounds, perhaps a little like human hormones.
Admittedly, I am still guessing, but hydrogen peroxide might release some oxygen free radicals or some other form of reactive oxygen. And those might mimic something seeds already use to break dormancy. Or maybe something reacts with H2O2 to produce those "signals".
Or, more simply, seeds "know" not to sprout unless they are in a plenty aerobic spot, and H2O2 assures that they "smell the oxygen".
Just speculation. I Googled :
ROS seed and
Reactive oxygen species and seed germination
