A subscription to JoVE is required to view this content. Sign in or start your free trial.
Studies of cell wall biomechanics are essential for understanding plant growth and morphogenesis. The following protocol is proposed to investigate thin primary cell walls in the internal tissues of young plant organs using atomic force microscopy.
The mechanical properties of the primary cell walls determine the direction and rate of plant cell growth and, therefore, the future size and shape of the plant. Many sophisticated techniques have been developed to measure these properties; however, atomic force microscopy (AFM) remains the most convenient for studying cell wall elasticity at the cellular level. One of the most important limitations of this technique has been that only superficial or isolated living cells can be studied. Here, the use of atomic force microscopy to investigate the mechanical properties of primary cell walls belonging to the internal tissues of a plant body is presented. This protocol describes measurements of the apparent Young's modulus of cell walls in roots, but the method can also be applied to other plant organs. The measurements are performed on vibratome-derived sections of plant material in a liquid cell, which allows (i) avoiding the use of plasmolyzing solutions or sample impregnation with wax or resin, (ii) making the experiments fast, and (iii) preventing dehydration of the sample. Both anticlinal and periclinal cell walls can be studied, depending on how the specimen was sectioned. Differences in the mechanical properties of different tissues can be investigated in a single section. The protocol describes the principles of study planning, issues with specimen preparation and measurements, as well as the method of selecting force-deformation curves to avoid the influence of topography on the obtained values of elastic modulus. The method is not limited by sample size but is sensitive to cell size (i.e., cells with a large lumen are difficult to examine).
The mechanical properties of the plant cell wall determine the shape of the cell and its ability to grow. For example, the growing tip of the pollen tube is softer than the non-growing parts of the same tube1. The primordia formation on Arabidopsis meristem is preceded by a local decrease in cell wall stiffness at the site of the future primordium2,3. The cell walls of Arabidopsis hypocotyl, which are parallel to the main growth axis and grow faster, are softer than those that are perpendicular to this axis and grow slower4,
1. Sample preparation for AFM measurements
Typical elastic modulus and DFL maps, as well as force curves obtained on rye and maize roots by the method described, are presented in Figure 2. Figure 2A shows elastic modulus and DFL maps obtained on the transverse section of rye primary root. The white areas in the modulus map (Figure 2A, left) correspond to an erroneous overestimation of Young's modulus due to the scanner reaching its limit in the z-direction.......
The mechanical properties of the primary cell walls determine the direction and rate of plant cell growth, and therefore the future size and shape of the plant. The AFM-based method presented here complements existing techniques which are used to study the properties of plant cell walls. It allows the elasticity of cell walls, which belong to the inner tissues of the plant, to be investigated. Using the presented method, the mechanical properties of cell walls in different tissues of the growing maize root were mapped, a.......
The authors have no conflicts of interest.
We would like to acknowledge Dr. Dmitry Suslov (Saint Petersburg State University, Saint Petersburg, Russia) and Prof. Mira Ponomareva (Tatar Scientific Research Institute of Agriculture, FRC KazSC RAS, Kazan, Russia) for providing maize and rye seeds, respectively. The presented method was developed within the framework of the Russian Science Foundation Project No. 18-14-00168 awarded to LK. The part of the work (obtaining of the results presented) was performed by AP with the financial support of the government assignment for the FRC Kazan Scientific Center of RAS.
....Name | Company | Catalog Number | Comments |
Agarose, low melting point | Helicon | B-5000-0.1 | for sample fixation |
Brush | - | - | for section moving |
Cantilevers | NanoTools, Germany | NT_B150_v0020-5 | Model: Biosphere B150-FM |
Cantilevers | NT-MDT, Russia | FMG01/50 | Model: FMG01 |
Cyanoacrylate adhesive | - | - | for vibratomy |
Glass slides | Heinz Herenz | 1042000 | for vibratomy and AFM calibration |
ImageAnalysis P9 Software | NT-MDT, Russia | - | for data analysis |
Leica DM1000 epifluorescence microscope | Leica Biosystems, Germany | 11591301 | for section check |
NaOCl | - | - | for seed sterilization |
Nova PX 3.4.1 Software | NT-MDT, Russia | - | for experiments conducting |
NTEGRA Prima microscope with HD controller | NT-MDT, Russia | - | for AFM and data acquisition |
Petri dish 35 mm | Thermo Fisher Scientific | 153066 | for sample fixation |
Tip pipette 1000 µL | Thermo Fisher Scientific | 4642092 | - |
Tip pipette 2-20 µL | Thermo Fisher Scientific | 4642062 | - |
Ultrapure water | - | - | - |
Vibratome Leica VT 1000S | Leica Biosystems, Germany | 1404723512 | for sample sectioning |
Request permission to reuse the text or figures of this JoVE article
Request PermissionThis article has been published
Video Coming Soon
Copyright © 2025 MyJoVE Corporation. All rights reserved