Hey I know I am relatively new to these boards, but I'm not that new to this game. While I have not attempted to graft any limbs from plant to another, I do know a little about grafting as I have a family member involved in agriculture, fruit trees in particular, and have seen some of it and had it explained. when you graft, no actual genetic material or DNA is from one part of the graft is used by the other part. its sort of like a transplanted organ. The usual reason for grafting is to attach a part of one plant which is fruit producing, but not particularly acclimated to a certain area, to another part from a different plant in the same species that is better adjusted to the region or growing conditions.
Say, for example, you have a particular soil type that is hard and rocky and only one variety of rosebush, or apple tree, or whatever, has a strong enough root system to grow well and give good results. but you, however, want to grow many different tropical varieties. you could grow the hardy variety until it has a strong root system, then you slice the little grooves and insert little starts from the tropical varieties and now they get to use the big tough root system that is the only one able to get what they need. the grafted "limb" gets to utilize the strength of the root system, but it does not change its DNA or take on traits from the plant you graft onto.
I'm not saying this topic isnt very cool. I think its sweet that anyone has done this, but i dont think it will make much difference in the final product. since cannibinoids are formed on the surface of calyxes and does not run through the plant like sap, it would be impossible for any psychoactive properties to be passed on by grafting. there could be uses for this in marijuana however, more research definitely needs to be done.
A possible application for this might be something like grafting branches from a very tall sativa onto the trunk/stalk of a short hardy indica and see if you could get big sativa buds on a trunk that isnt 10 feet tall. anyway, keep up the grafting.