Laboratoire Matière et Systèmes Complexes

Anja Geitmann

Université de Montréal

Département de Sciences Biologiques

The challenge of making a tube - cellular morphogenesis with focus

Shape formation in plant cells is regulated through modulation of the mechanical properties of the cell wall. Both spatial control (geometry) and temporal control (long term and short term kinetics) of the growth process depend on how the material properties of the wall are regulated. The pollen tube is a highly polarized cellular protuberance that serves to deliver the male gametes from the pollen grain to the female gametophyte nestled within the flower tissues. Pollen tube growth occurs unidirectionally and the resulting shape is axially symmetric thus providing an ideal system for mechanical modelling. Moreover, similar to other tip growing cells such as fungal hyphae, the pollen tube is able to invade other tissues, in this case those of the receptive flower. To be competitive, the pollen tube elongates extremely rapidly and it has to do so against the impedance of the apoplast of the transmitting tissue. The force required for this invasive activity is generated by the turgor pressure, but its magnitude and timing are regulated by the cell wall as can be investigated using microfluidic obstacle courses. We use a combination of micro-engineering and modelling to understand this central aspect of the reproductive process in plants.