Fig. 3. Quantification of growth and shrinkage rates in wild type and mor1-1 at 21°C and 31°C. Growth and shrinkage rates calculated from time-lapse images of microtubules expressing GFP-TUB as described in Fig. 1 are presented as frequency distribution histograms. Mean values are shown in the insets. (A) Growth rates at 21°C. (B) Growth rates at 31°C. (C) Shrinkage rates at 21°C. (D) Shrinkage rates at 31°C. Shrinkage rates greater than –22 µm/minute are shown as one data group (). Data were collected from 115 microtubules from six cells from four different plants for wild type at 21°C, 28 microtubules from seven cells from four different plants for wild type at 31°C, 98 microtubules from five cells from three different plants for mor1-1 at 21°C, and 26 microtubules from 12 cells from nine different plants for mor1-1 at 31°C.