GAMMA-TUBULIN IN TOBACCO POLLEN TUBES - ASSOCIATION WITH GENERATIVE CELL AND VEGETATIVE MICROTUBULES

gamma-Tubulin was localized in tobacco pollen tubes using an antibody raised against a peptide conserved in all known gamma-tubulins. Antibo dy staining occurs in a primarily punctate pattern along the length of the microtubule bundles in generative cells and along cortical microt ubules in the vegetative cytoplasm. During generative cell division, g amma-tubulin is localized in the forming mitotic apparatus. By metapha se, it is present along kinetochore fibers except at their plus ends l ocated at the kinetochores. By telophase, staining is observed in the phragmoplast, where it again avoids the plus ends of microtubules at t he cell plate, gamma-Tubulin is also present at the periphery of the s perm nuclei. A patch of intense staining on the distal side of each nu cleus marks the site of assembly of a new population of sperm microtub ules. No specific fluorescence is present in control pollen tubes trea ted with preimmune IgG. These localization patterns bear similarities to those seen in somatic cells and in addition may help explain change s in microtubule arrays between generative cells and sperm.