Fig. 2. Directions of elongation of roots in vermiculite at various water potentials 2 d after transplanting. Transplanted seedlings were located in both the wet and the dry vermiculite at sites where no water potential gradient was detected (WET and DRY, respectively), and in the dry vermiculite at 60 and 80 mm from the boundary between the wet and the dry vermiculite where there was a steep water potential gradient (60 and 80 mm, respectively). Bars show the relative numbers of roots in each test group that elongated in each direction [towards the wet vermiculite, left (black bars); towards the dry vermiculite, right (grey bars); no bending, middle (open bars)]. The vertical axis shows the relative numbers of roots that curved in each direction. See also Table 1.