Biomechanical modelling of anther dehiscence and pollen release

M.R. Nelson, L.R. Band, R.J. Dyson, K.J. Heymer, J. Hiorns, O.E. Jensen, A. Korn, T. Lessinnes, S. Pearce, S. Thomas, D.L.K. Toner, F. Xu & C. Yang

Understanding the processes which underlie pollen release is key to efficient production of hybrid crops. Pollen is produced in compartments termed locules, which reside within the anther. Surrounding the locules are two cell layers: an outer epidermis and an inner endothecium. During pollen development, endothecial cells undergo secondary thickening – a process by which cell walls are lined by a helical arrangement of lignin fibres, strengthening the layer and providing a natural resistance to bending. Pollen release occurs as a result of an anther dehiscence process, during which the anther wall splits, exposing the pollen to the environment. A number of processes have been proposed to drive this process. In this report, we examine one such process: that in which anther dehiscence is driven by dehydration of the epidermis, which results in contraction of this layer and an associated change to the preferred curvature of the locule. We extend an existing bilayer model to incorporate expansion and contraction of both cell layers, and use cell-scale models to determine the associated parameters in terms of experimentally measurable quantities. We present brief experimental validation of this hypothesis, in which the response of lily anthers to external hydration/dehydration is observed, and use the associated biomechanical model to explain the observed changes in the anther’s configuration.

Proceedings of the 4th Mathematics in the Plant Sciences Study Group