Pollen Tubes: An Excellent Model
Pollen tubes are an excellent model for the understanding of plant cell behavior. They are easily cultivated in vitro and have a very dynamic cytoskeleton that polymerizes at very high rates, providing the pollen tube with interesting mechanical properties. The pollen tube has an unusual kind of growth; it extends exclusively at its apex. Extending the cell wall only at the tip minimizes friction between the tube and the invaded tissue. This tip growth is performed in a pulsating manner rather than in a steady fashion. Remarkably, the pollen tube’s journey through the style often results in depth-to-diameter ratios above 100:1 and up to 1000:1 in certain species, whereas classic mechanical drilling is often only effective up to 15:1 ratios. However, the internal machinery and the external interactions that govern the dynamics of pollen tube growth are far from being fully understood.
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