A surface morphology-based inference method for the cell wall elasticity profile in tip-growing cells
Discuss this preprint
Start a discussion What are Sciety discussions?Listed in
This article is not in any list yet, why not save it to one of your lists.Abstract
Plant cell morphology and growth are essential for plant development and adaptation, in particular the cell wall material deposition and rearrangement. As the wall is extended due to turgor pressure, the wall mechanical response, specifically the wall’s elastic properties, are not well understood. In this study, we introduce a new surface morphology-based method to measure the elasticity of the cell wall in tip-growing cells. Previous work is based on the wall meridional outline on the assumption the cell is axisymmetric, an idea that does not align well with the reality of the cells. Instead, we developed a way to triangulate the surface of the cell using marker point locations that could be achieved experimentally with fluorescent labeling. After measuring the elastic stretch and curvatures from our triangulation, a mechanical model is used to measure the tensions and surface bulk modulus distribution. We simulated moss tip cells from experimental Physcomitrium patens plants to challenge the method with noise estimated from experiments. We discovered that increasing the discretization of the triangulation improved robustness against noise. With multiple cell sampling, we found that around 10 cells were sufficient to recover the elasticity distribution with noise, but only when the elastic stretches were high enough at the tip. With low elastic stretch at the tip, the appearance of non-physical modulus values led to underestimated inference values there, causing false-positive gradient results. This compelled us to study a range of cases, leading us to a dimensionless global phase map showing areas of good inference. This technique will open the field to more comprehensive measurements of tip cell elasticity, providing a key step in understanding tip cell growth and morphogenesis.
Author summary
Tip-growing cells can be characterized by their fast growth concentrated at the cell’s apex. Their growth and morphogenesis are tightly regulated processes involving cell wall addition and rearrangement, which aim to reduce the wall stress originating from the cell’s internal turgor pressure. We simplify this cell growth system by first studying the cell wall’s elastic properties that are present without active growth. We use a surface triangulation method derived from marker point tracking to measure the spatial elasticity along the tip cell. In this work, we present a parameter sensitivity study of this method on synthetic cells that cover a tapered and round cell morphology. Our results suggest that this inference method can reliably measure a cell wall elasticity gradient under combined geometric and mechanical conditions that create large enough elastic strain at the tip.
