Program
| MSG1c | |
|---|---|
| Anja Geitmann | |
| Institut de recherche en biologie végétale, Université de Montréal, Canada | |
| Title | Coordination of material supply and growth - vesicle delivery in pollen tubes |
| Abstract | Tip growing plant cells generate a cylindrical cell by surface expansion at the apical end. In pollen tubes this spatially confined, rapid growth activity requires enormous amounts of pectic cell material to be delivered to the growth site at high rates and with precise targeting. The spatio-temporal movement patterns of exocytotic vesicles in growing pollen tubes are controlled by the actin cytoskeleton. Remarkably, the target region at the apical pole of the cell does not contain much filamentous actin. We model the vesicular trafficking using as boundary conditions the expanding cell wall and the actin array forming the apical actin fringe. Dynamic advancement of the fringe was obtained by imposing a steady shape and constant polymerization rate of the actin filaments. Letting vesicle flux into and out of the apical region be determined by the orientation of the actin microfilaments and by exocytosis was sufficient to generate a flow that corresponds in magnitude and orientation to that observed experimentally. This model explains how the cytoplasmic streaming pattern in the apical region of the pollen tube can be generated without the presence of actin microfilaments. (Joint work with Jens Kroeger and Firas Bou Daher) |
| Location | Woodward 1 |