The apical meristem and zone of cell extension of impeded roots is shorter (Barley, 1962; Souty, 1987), and root hairs develop closer to the tip of impeded roots (Goss & Russell, 1980). Lateral initiation occurs nearer the tip and laterals occur together along the impeded axis (Goss & Russell, 1980; Barley, 1962). Where mechanical deflection causes roots to curve around an obstacle, the initiation of laterals generally occurs on the convex side of the root (Goss & Russell, 1980). Root hair development is greater on the opposite (concave) side and, in.
