Sure. Look up "shikimic acid pathway" for a start and I'll look up some specifics. Like cyanide it only blocks one chemical step but once it's stopped that's it. There's no way round, you turn blue and it's over. As to how far, how fast, well how long is a piece of string? A big root system will stand up for longer than a leafy plant, and it's dose dependant. Obviously one molecule won't kill a whole plant any more than one molecule of cyanide will kill me. Things like jap kw, with a corm and substantial reserves, will tough it out more than something that's all leaf. It's species depend ent, broad leaf plants are less resistant than grasses. However once in the plant in sufficient quantity it will kill it. It is transported in sap. That's why it takes 3-4weeks.