Polarity is the orientation inherent in a stem or root cutting. The distal end is nearest to the stem or root tip, while the proximal end is closest to the root-shoot junction.
Auxin moves in a polar manner from the distal to proximal ends of cuttings. Maintaining polarity is important to decide which end of cuttings to stick into the medium.
This root cutting of horseradish illustrates how shoots will form on the proximal portion of the root.
This will occur regardless of the orientation of the cutting in the substrate.