Acropetal penetrants
From PLANTFACTS.OSU.EDU
1. A class of fungicide that enters the plant and is translocated (translocation) upward within the plant through the xylem by way of the transpiration stream.

This illustration shows the upward (acropetal) movement of flowering information. A penetrant would also move upward through the plant.
Source: http://www.biologie.uni-hamburg.de/b-online/virtuallaboratory/Section-10.html#acropetal
