Measuring the Mechanical Properties of Plant Cell Walls

Abstract

The size, shape and stability of a plant depend on the flexibility and integrity of its cell walls, which, at the same time, need to allow cell expansion for growth, while maintaining mechanical stability. Biomechanical studies largely vanished from the focus of plant science with the rapid progress of genetics and molecular biology since the mid-twentieth century. However, the development of more sensitive measurement tools renewed the interest in plant biomechanics in recent years, not only to understand the fundamental concepts of growth and morphogenesis, but also with regard to economically important areas in agriculture, forestry and the paper industry. Recent advances have clearly demonstrated that mechanical forces play a crucial role in cell and organ morphogenesis, which ultimately define plant morphology. In this article, we will briefly review the available methods to determine the mechanical properties of cell walls, such as atomic force microscopy (AFM) and microindentation assays, and discuss their advantages and disadvantages. But we will focus on a novel methodological approach, called cellular force microscopy (CFM), and its automated successor, real-time CFM (RT-CFM).

Diffuse Growth of Plant Cell Walls

“…Sometimes this is a matter of convenience-elasticity is relatively straightforward to incorporate into simulations of growth (Fayant et al, 2010;Huang et al, 2015)-and numerous methods have been devised in recent years to measure elasticity of tissues and cells with mechanical devices (e.g. Routier-Kierzkowska et al, 2012;Nezhad et al, 2013;Beauzamy et al, 2015b;Vogler et al, 2015;Mosca et al, 2017). To be fair, there are indeed cases where elasticity roughly correlates with cell growth, as discussed below.…”

A computational approach for inferring the cell wall properties that govern guard cell dynamics

“…cellulose, lignin and hemicellulose, are known, and the modulus for the whole tissue lies in the range spanned by the moduli, with the value dependent on the relative abundance of each component (Gibson, 2012). A variety of experimental techniques have been used to quantify elastic moduli in plants (reviewed by Vogler et al, 2015). For example, tension devices have been used to test cell wall sheets of Chara corallina (Toole et al, 2001), plant cell wall analogues (Chanliaud et al, 2002), Arabidopsis hypocotyls (Ryden et al, 2003) and Prunus avium (sweet cherry) fruit skin (Bargel et al, 2004).…”

Probing the effect of tip pressure on fungal growth: Application toAspergillus nidulans

“…Central to the function and development of living cells is mechanical deformability. Previous works have shown how mechanical deformability influences many biological processes in animal biology, such as migration of blood and immune cells [12], stem cell differentiation [13], and cancer [14], while in plant cells several studies have described the role of the mechanical properties of the wall in stability and resistance against pathogens [15]. In fungal cells and other tip-growing cells, some studies have reported different cell wall properties at the elongating tip from those in the lateral wall, showing how mechanical deformability accounts for the rod-shaped hyphae [16,17].…”

“…However, local differences in the mechanical properties of the cell wall cannot be assessed with this technique. Moreover, in techniques such as optical or magnetic tweezers, the force range is too low to measure the mechanical parameters of cells with walls [15].…”