I've read a few articles over the years of top scientists using electricity to produce bigger better plants...
I did it once but I had nothing to compare. Just got the voltage and direction of flow down. If it was too high or had positive on plant then it would burn.
My observations showed that the amount of materials this could force into the plant is very substantial. Even @9vdc. If a system were specially designed it could go full retard. I wrapped the neg around the main stem and jammed wires with gold pins into the pebbles around the roots. If I didn't watch it closely the pin would be completely consumed.
This reminds me of the scene in Cheech and Chong when the guy has electric current running through one of his plants. Slightly off topic, but just really sticks out in my mind from years ago. Anyways, this sounds like something I would be down to test out. I did some experiments on beet growth using electricity back in college. maybe I still have the research on it... hmmmmm.
Here is another GC user who is using electroculture. http://forum.grasscity.com/advanced-growing-techniques/620211-electro-culture-experiment-50-65-yeild-increase.html