Figure 5.

Curvature development in the root grown at 28°C between t = 6.8 and 17.5 h. At t = 6.8 h, θ was set to 45° from 90°. Root shape is given by two to three centerlines per frame (solid, dotted, and long-dashed, with increasing t). The gray lines indicate the positions of the root in the previous frames. The point at which the first root hairs were observed in each of these time intervals is given by a set of symbols (black circle, white circle, and square). Bending near the root apex (putatively tropic) is denoted by the symbol T, whereas bending throughout the root (putatively nontropic) is denoted by the symbol B. These forms of bending are distinguished by whether the section of root is near the tip and by their direction of curvature. See Supplemental Video 1 for the original time-lapse image source of this sequence.