DYNEIN-RELATED POLYPEPTIDES IN POLLEN AND POLLEN TUBES

Microtubules in pollen tubes are evident within the vegetative and gen erative cell cytoplasm. This observation led to the formulation of sev eral hypotheses regarding the role of microtubules in cytoplasmic move ment and the migration of the vegetative nucleus/generative cell along the pollen tube. The study of microtubular motor proteins in pollen t ubes followed the discovery and characterization of an immunoreactive homolog of mammalian kinesin in tobacco pollen tubes, Recent identific ation of dynein-related polypeptides in pollen tubes of Nicotiana taba cum and pollen of Ginkgo biloba is a significant step in the definitio n of the role of microtubule function within pollen and pollen tubes.