Cellular Force Microscopy for in Vivo Measurements of Plant Tissue Mechanics    

Abstract

Although growth and morphogenesis are controlled by genetics, physical shape change in plant tissue results from a balance between cell wall loosening and intracellular pressure. Despite recent work demonstrating a role for mechanical signals in morphogenesis, precise measurement of mechanical properties at the individual cell level remains a technical challenge. To address this challenge, we have developed cellular force microscopy (CFM), which combines the versatility of classical microindentation techniques with the high automation and resolution approaching that of atomic force microscopy. CFM's large range of forces provides the possibility to map the apparent stiffness of both plasmolyzed and turgid tissue as well as to perform micropuncture of cells using very high stresses. CFM experiments reveal that, within a tissue, local stiffness measurements can vary with the level of turgor pressure in an unexpected way. Altogether, our results highlight the importance of detailed physically based simulations for the interpretation of microindentation results. CFM's ability to be used both to assess and manipulate tissue mechanics makes it a method of choice to unravel the feedbacks between mechanics, genetics, and morphogenesis.

Matching Patterns of Gene Expression to Mechanical Stiffness at Cell Resolution through Quantitative Tandem Epifluorescence and Nanoindentation

“…Data sets were extracted based on the labels. Except for the SAM in Figure 1, we have only presented data corresponding to anticlinal walls, because our experimental setup was better suited to examining such walls (Peaucelle et al, 2011;Routier-Kierzkowska et al, 2012).…”

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.…”

AFM-based Mapping of the Elastic Properties of Cell Walls: at Tissue, Cellular, and Subcellular Resolutions

“…With the AFM, the required tissue, cellular, and subcellular resolutions can be achieved [8][9][10] . Recently several protocols have been developed specifically to measure mechanics of plants tissue that could also be used 11,12 .…”