Modelling cytosolic flow and vesicle transport in the growing pollen tube

Tyrrell, James ORCID: 0000-0002-2344-737X (2019). Modelling cytosolic flow and vesicle transport in the growing pollen tube. University of Birmingham. Ph.D.

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Abstract

Scientific interest in the mathematical modelling of pollen tube growth has increased steadily over the last few decades. The highly localized and rapid nature of this growth necessitates large--scale actomyosin transport of cellular material throughout the cell cytoplasm. This directed movement of cellular material induces a flow in the cytosol, also known as 'cyclosis'. The extent to which inclusion of this flow is important to modelling the distribution of elements in the cytoplasm is currently unclear, with its effect often conflated with that of actomyosin transport. In this thesis, a finite volume method (FVM) is developed for the numerical evaluation of transport equations describing vesicle distribution in the pollen tube cytoplasm. This is coupled with a novel method of regularized ringlets, derived via analytical azimuthal integration of the regularized Stokeslet, for obtaining numerical solutions to axisymmetric Stokes flows. Using this method of regularized ringlets, we present an axisymmetric velocity profile for cytosolic flow in the pollen tube based on the drag induced by actomyosin vesicle transport. When used in the transport equation for vesicle distribution, we find that recreation of the apical `inverted vesicle cone' requires the use of an enlarged effective fluid viscosity amongst other results.

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

Supervisor(s):