Elastic shell theory for plant cell wall stiffness reveals contributions of cell wall elasticity and turgor pressure in AFM measurement

Abstract

Abstract The stiffness of a plant cell in response to an applied force is determined not only by the elasticity of the cell wall but also by turgor pressure and cell geometry, which affect the tension of the cell wall. Although stiffness has been investigated using atomic force microscopy (AFM) and Young’s modulus of the cell wall has occasionally been estimated using the contact-stress theory (Hertz theory), the existence of tension has made the study of stiffness more complex. Elastic shell theory has been proposed as an alternative method; however, the estimation of elasticity remains ambiguous. Here, we used finite element method simulations to verify the formula of the elastic shell theory for onion ( Allium cepa ) cells. We applied the formula and simulations to successfully quantify the turgor pressure and elasticity of a cell in the plane direction using the cell curvature and apparent stiffness measured by AFM. We conclude that tension resulting from turgor pressure regulates cell stiffness, which can be modified by a slight adjustment of turgor pressure in the order of 0.1 MPa. This theoretical analysis reveals a path for understanding forces inherent in plant cells.

Plant phenotyping relevance

AFMで測定した細胞の見かけの剛性と細胞曲率から、有限要素シミュレーションで検証した弾性殻理論により、植物細胞の膨圧と弾性を定量化する方法を開発・検証しており、表現型取得が中心です。

Code and data availability

The paper's AFM force–indentation measurements, AFM topography images, and FEM simulation parameters are paper-specific phenotyping assets, but they are not publicly deposited; the authors state they are available only on request. No public code, dataset, or repository URL is provided.

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