It may be possible to inject the plant with pure clean spring water but i think that the root system acts like our own digestive system and that this would only work on tuberous fruit bearing plants,i.e. cucumbers,tomatoes,marrows etc..
Try it on a male and see,i cannot believe that this would be of any great benefit to cannabis and using nutes would probably kill it.
It may however be possible,i suppose,to possibly inject it with a very weak solution of b12 and water and this may possibly be of benefit to a waning or weak plant,all though this would be only a supposition on my part.
I will try this idea on a male sometime in the future and let you know what happened for me