Not sure about the question...

However, if you meant, if there is internal transport system within plant, than there is. And it is one of the wonders of Nature. While there exist also passive route of transport in the plant (being carried in the veins within the sap), it is the active transport - dubbed "polar auxin transport" which completely define plant.

And I mean it. Without perfect spatio-temporal coordination of transport of auxin molecules between various cells within the plant body .. there would be no body, no shape, no growth. Auxin can be understood as a kind of unit of information in cell-to-cell communication. Different cells in a body have different task and they have to get the right task at the right position at the right time.

There is are no nerves in plants. The body still needs to be cohesive coordinated internally communicating unit.

How does it achieve it?
Slowly - by exchanging, transmuting (metabolism) and perceiving units of auxin from and to their surroundings. (And to a lesser extent of other phytohormones too).

Without this coordination - all the plant cells within body would be more or less the same and instead of body growing to the light and moisture - we would get unorganized heap of biological matter without capacity to survive on their own.

And yes all of this is driven by internal "delivery system". The delivery system in its own right is difficult to explain in detail. In short it is composed of various proteins on the membranes serving as directional pumps ... some are pumping in, some pumping out (of the cell) ... and all of them has different set of regulations from the other ones.

To know more .. try to google out "Polar auxin transport" and "auxin efflux carriers"