The mechanical properties of plant cell walls soft material at the subcellular scale: the implications of water and of the intercellular boundaries
- 516 Downloads
Subcellular mechanical characterization of the cell wall can provide important insights into the cell wall’s functional organization, especially if the characterization is not confounded by extracellular factors and intercellular boundaries. However, due to the technical challenges associated with the microscale mechanical characterization of soft biological materials, subcellular investigations of the plant cell wall under tensile loading have yet to be properly performed. This study reports the mechanical characterization of primary onion epidermal cell wall profiles using a novel cryosection-based sample preparation method and a microelectromechanical system-based tensile testing protocol. At the subcellular scale, the cell wall showed biphasic behavior similar to tissue samples. However, instead of a transition zone between the linear elastic or viscoelastic and linear plastic zones, the subcellular-scale samples showed a plateau-like trend with a sharp drop in the modulus value. The critical ranges of stress (20–40 MPa) and strain (5–12 %) of the plateau zone were identified. A strain energy of 1.3 MJ m−3 was calculated at the midpoint of the critical stress–strain range; this value was in accordance with the previously estimated hydrogen bond energy of the cell wall. Subcellular-scale samples showed very large lateral/axial deformations (0.8 ± 0.13) at fracturing. In addition, investigating the cell wall’s mechanical properties at three different water states showed that water is critical for the flow-like behavior of cell wall matrix polymers. These results at subcellular scale provide new insights into biological materials that possess a structural hierarchy at different length scales; which cannot be obtained from tissue-scale experiments.
KeywordsCell Wall Cellulose Microfibril Middle Lamella Pectic Polysaccharide Periclinal Wall
This study was funded by the Center for Lignocellulose Structure and Formation, an Energy Frontier Research Center funded by the U. S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Award Number DE-SC0001090.
Compliance with Ethical Standards
Conflict of interest
The authors declare that they have no conflict of interest.
- 1.Keegstra K (2010) Plant cell walls. Plant Physiol 154:483–486. doi: 10.1104/pp.110.161240
- 3.Harris PJ, Stone BA (2008) Chemistry and molecular organization of plant cell walls. Biomass Recalcitrance. Blackwell Publishing Ltd., pp 61–93Google Scholar
- 6.Albersheim P, Darvill A, Roberts K (2010) Plant cell walls: from chemistry to biology. Garland Science, Garland.Google Scholar
- 22.Konstankiewicz K, Pawlak K, Zdunek A (2001) Influence of structural parameters of potato tuber cells on their mechanical properties. Int Agrophys 15:243–246Google Scholar
- 23.Waldron KW, Brett CT (2007) The role of polymer cross-linking in intercellular adhesion. In: Roberts JA, Gonzalez-Carranza Z (eds) Plant cell separation and adhesion. Blackwell Publishing Ltd, Ames, pp 183–204Google Scholar
- 25.Höfte H, Peaucelle A, Braybrook S (2012) Cell wall mechanics and growth control in plants: the role of pectins revisited. Front Plant Sci 3:6Google Scholar
- 34.Peaucelle A (2014) AFM-based Mapping of the elastic properties of cell walls: at tissue, cellular, and subcellular resolutions. e51317. doi: 10.3791/51317
- 37.Kasas S, Gmur T, Dietler G (2008) The world of nano-biomechanics. 221–243. doi: 10.1016/B978-044452777-6.50014-0
- 46.Moore JP, Farrant JM, Driouich A (2008) A role for pectin-associated arabinans in maintaining the flexibility of the plant cell wall during water deficit stress. Plant Signal Behav 3:102–104Google Scholar
- 56.Evert RF (2006) Esau’s pant anatomy, 3rd edn. Wiley, New York, p 601Google Scholar
- 60.Zdunek A, Pieczywek PM (2013) Study on model development of plant tissue using the finite element method. Inside Food Symposium, Leuven, Belgium, pp 9–12Google Scholar
- 65.Spatz H, Kohler L, Niklas KJ (1999) Mechanical behaviour of plant tissues: composite materials or structures? J Exp Biol 202:3269–3272Google Scholar
- 69.Timoshenko S, Goodier JN (1984) Theory of elasticity, 3rd edn. Singapore, McGraw-Hill, AucklandGoogle Scholar
- 77.McCann MC, Wells B, Roberts K (1990) Direct visualization of cross-links in the primary plant cell wall. 96:323–334Google Scholar
- 78.Ha MA, Apperley DC, Jarvis MC (1997) Molecular rigidity in dry and hydrated onion cell walls. Plant Physiol 115:593–598Google Scholar