XVI International Botanical Congess

It is well documented that an intact actin cytoskeleton is necessary for pollen tube growth, however, the mechanism of this dependency remains unknown. Actin could participate in this process either directly, by polymerization, or indirectly, by transporting secretory vesicles. We have analyzed this problem by gradually inhibiting actin activity with profilin, DNAse I and latrunculin B in the live cell. All the tested inhibitors have a more pronounced effect on pollen tube growth than on cytoplasmic streaming. These observations question the conventional view that actin dependent growth is simply due to the associated transport of vesicles, and introduces support for an independent role of actin assembly as a crucial factor in controlling pollen tube elongation.