Don't know much about plant's as i just started off with Java ferns, I think some plants are oxygenating and will see bubbles, hope someone will give you a better explanation. What sort of plants do you have?
SUppose its good, photosynthesis = rapid = growth?
Altnerantively it could just be your filter is making alot of bubbles which are sticking to the plant leaves/surfaces. Thats whats happeneing in my tank (low light .7WPG)
If it's a jelly like bubble, as opposed to an air-bubble, it's more likely to be snails' eggs. I asked a similar question not so long ago, and that's what I was told.