Figure 10.

In water-stressed roots the handedness of helical orientations of microfibrils is in many cells opposite to that of the microtubules. Percentage of cortical cells with various classes of orientations of microtubules (MT, white bars) and microfibrils (MF, black bars) at 6 mm (A), 7 mm (B), 10.5 mm (C), and 11.5 mm (D) from the apex are shown. Percentages of cells with undefined (Un), transverse (Tr), right-handed helical (Rt), longitudinal (Long), and left-handed helical (Lft) orientations are also shown. Orientations of each element were measured in the same sections. Data for microtubules are means of 100 to 140 cells, and for microfibrils of 270 to 560 cells, from single median-longitudinal sections from five to seven roots.