Not hydrogen storage for seed dispersal, but Larry Niven's Known Space series featured Stage Trees. These were plants genetically engineered to be solid fuel rockets. They grew to be quite large, multistage launchers. When they ignited, they dispersed their seeds to other planets.
to add to this, I just listened to a podcast called StarTalk [0] where Neil deGrasse Tyson interviewed James Cameron [1]. James Cameron stated the idea for some of the plants actually come from personally scuba diving and seeing some plants react the way they did in the movie (specifically when you touch them move or close up)
James Cameron stated he has been a passionate scuba diver and it was a slight nod to others who may have had similar experiences.