FRAP showing only growth (or transport) of MTs restores fluorescence to the bleached area. (A) GFP-tubulin in a plated FDB fiber before (prebleach), just after (bleach), and 28 s after photobleaching of two regions of interest surrounded by orange boxes. For quantitation of recovery (B), the lower box was divided into parts 2 and 3. In seven independent photobleachings, more than half of the bleached boxes recover some fluorescence, as is the case in box 3, by growth or transport of a MT distinct from the original one (A, arrows). Bar, 2 µm.