Plant Biomechanics

Julian FV Vincent, University of Bath, Bath, UK

Published online: May 2011

DOI: 10.1002/9780470015902.a0002062.pub2

Abstract

The mechanical design of plants is based on the tensile properties of cellulose molecules which combine to form stiff nanofibrils from which the wall surrounding all plant cells is mainly constructed. Simple plants such as liverworts are made from few cell types and rely for their stiffness on the osmotically maintained pressure (turgor) of water inside the cell reacting against the stiff cellulose. As plants evolved and grew towards the light they developed larger fibres which transmit the forces more effectively and convert the plant into a complex pre‐stressed structure, but still largely dependent on water pressure for its rigidity. Increased structural complexity leads to increased fracture resistance and durability. Lignin glues the nanofibrils together so that the fibres, and then the cell walls in general, can take compressive forces, and tall herbs and trees evolve. Some plants (lianas, creeping herbs, Spanish moss, etc.) can grow large relying on simple tension under gravitation.

Key Concepts:

  • Cellulose is the commonest, and most technically most useful and important, biological fibre‐forming molecule.

  • The cell wall is a composite material of fibres in a matrix.

  • Since the plant cell wall is a relatively open fibrous structure, it is very difficult to ascribe unique mechanical properties to it. This variability gives it adaptability.

  • Intrinsically plants move slowly using turgor, but they can move quickly by storing elastic energy over time and releasing it suddenly. This is called power amplification.

  • The more cells, the more tissue types are possible and the plants can be larger and more adaptive.

  • Cellulose is distributed nonuniformly in a way that maximises its effectiveness.

  • Lignified tissues are mostly dead and so are simple prototypes for biomimetics.

Keywords: plant; cell wall; cellulose; turgor; stiffness; fracture

Figure 1.

Production of cellulose fibril from an enzyme (cellulose synthetase) ‘floating’ in the cell membrane and guided by one or more microtubules beneath the cell membrane. Adapted from Burgert and Fratzl with permission from Oxford University Press.
Figure 2.

The cell wall is made of cellulose fibrils joined together by more flexible and smaller strands of cellulose (hemicellulose). The spaces between the fibrils are filled with pectin and water. The middle lamella (top) forms the boundary between the cell walls and the cell membrane (bottom) surrounds the cell.
Figure 3.

Three cylindrical cells with different orientations of cellulose fibrils in the cell wall (top row) and the change in shape when the cell is pressurised. The stiff fibrils stop the cell from stretching, but they can separate laterally. Thus the cell can increase in diameter (a) or length (b) or in both directions (c).
close

References

Anon (1999) Wood Handbook – Wood as an Engineering Material. Madison, WI: Forest Products Laboratory.

Atkins AG and Vincent JFV (1984) An instrumented microtome for improved histological sections and the measurement of fracture toughness. Journal of Materials Science Letters 3: 310–312.

Brett CT and Waldron KW (1996) Physiology and Biochemistry of Plant Cell Walls. London: Chapman & Hall.

Burgert I (2006) Exploring the micromechanical design of plant cell walls. American Journal of Botany 93: 1391–1401.

Burgert I and Fratzl P (2009a) Actuation systems in plants as prototypes for bioinspired devices. Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 367: 1541–1557.

Burgert I and Fratzl P (2009b) Plants control the properties and actuation of their organs through the orientation of cellulose fibrils in their cell walls. Integrative and Comparative Biology 49: 69–79.

Cameron KM, Wurdack KJ and Jobson RW (2002) Molecular evidence for the common origin of snap traps among carnivorous plants. American Journal of Botany 89: 1503–1509.

Chen CS and Ingber DE (1999) Tensegrity and mechanoregulation: from skeleton to cytoskeleton. Osteoarthritis and Cartilage 7: 81–94.

Dawson C, Vincent JFV and Rocca A‐M (1997) How scales open in female pine cones. Nature 390: 668.

Easterling KE, Harrysson R, Gibson LJ et al. (1982) On the mechanics of balsa and other woods. Proceedings of the Royal Society A 383: 31–41.

Eichhorn SJ, Baillie CA, Zafeiropoulos N et al. (2001) Current international research into cellulosic fibres and composites. Journal of Materials Science 36.

Farquhar T and Zhao Y (2006) Fracture mechanics and its relevance to botanical structures. American Journal of Botany 93: 1449–1454.

Forterre Y, Skotheim JM, Dumais J et al. (2005) How the Venus flytrap snaps. Nature 433: 421–425.

Geitmann A (2006) Experimental approaches used to quantify physical parameters at cellular and subcellular levels. American Journal of Botany 93: 1380–1390.

Green PB (1999) Expression of pattern in plants: combining molecular and calculus‐based biophysical paradigms. American Journal of Botany 86: 1059–1076.

Hepworth DG and Vincent JFV (1998) Modelling the mechanical properties of xylem tissue from tobacco plants (Nicotiana tabacum ‘Samsun’) by considering the importance of molecular and micromechanisms. Annals of Botany 81: 761–770.

Hepworth DG and Vincent JFV (1999) The growth response of the stems of genetically modified tobacco plants (Nicotiana tabacum ‘Samsun’) to flexural stimulation. Annals of Botany 83: 39–43.

Hobson RN, Hepworth DG and Bruce DM (2001) Quality of fibre separated from unretted hemp stems by decortication. Journal of Agricultural Engineering Research 78: 153–158.

Hush JM and Overall RL (1992) Re‐orientation of cortical F‐actin is not necessary for wound‐induced microtubule re‐orientation and cell polarity establishment. Protoplasma 169: 97–106.

Jaffe MJ and Biro R (1979) Thigmomorphogenesis: the effect of mechanical perturbation on the growth of plants, with special reference to anatomical changes, the role of ethylene and interactions with other environmental stresses. In: Massel H and Staples R (eds) Stress Physiology in Crop Plants. New York: Wiley and Sons.

Jeronimidis G (1976) The work of fracture of wood in relation to its structure. In: Baas P, Bolton AJ and Catling DM (eds) Wood Structure in Biological and Technological Research, pp. 253–265. Leiden: University Press.

Khan AA and Vincent JFV (1993) Compressive stiffness and fracture properties of apple and potato parenchyma. Journal of Texture Studies 24: 423–435.

Khan AA and Vincent JFV (1996) The measurement of mechanical damage induced by controlled freezing in apple and potato. Journal of Texture Studies 27: 143–157.

King MJ, Vincent JFV and Harris W (1996) Curling and folding of leaves of monocotyledons – a strategy for structural stiffness. New Zealand Journal of Botany 34: 411–416.

Koehler L and Telewski FW (2006) Biomechanics and transgenic wood. American Journal of Botany 93: 1433–1438.

Kull U, Herbig A and Otto F (1992) Construction and economy of plant stems as revealed by use of the bic‐method. Annals of Botany 69: 327–334.

Lang JM, Eisinger WR and Green PB (1982) Effects of ethylene on the orientation of microtubules and cellulose microfibrils of pea epicotyl cells with polylamellate cell walls. Protoplasma 110: 5–14.

Lucas PW, Cheng PY, Choong MF et al. (1997) The toughness of plant tissues. Plant Biomechanics Reading 109–114.

Moulia B (1994) The biomechanics of leaf rolling. Biomimetics 2: 267–280.

Moulia B, Coutand C and Lenne C (2006) Posture control and skeletal mechanical acclimation in terrestrial plants: implications for mechanical modeling of plant architecture. American Journal of Botany 93: 1477–1489.

Parr AJ, Waldron KW, Ng A et al. (1996) The wall‐bound phenolics of Chinese water chestnut. Journal of the Science of Food and Agriculture 71: 501–507.

Preston RD (1974) The Physical Biology of Plant Cell Walls. London: Chapman & Hall.

Schopfer P (2006) Biomechanics of plant growth. American Journal of Botany 93: 1415–1425.

Sibly RM and Vincent JFV (1997) Optimality approaches to resource allocation in woody tissues. In: Bazzaz FA and Grace J (eds) Plant Resource Allocation. San Diego: Academic Press.

Spatz H‐C, Speck T and Vogellehner D (1990) Contributions to the biomechanics of plants. II. Stability against buckling in hollow plant stems. Botanica Acta 103: 123–130.

Speck T, Spatz H‐C and Vogellehner D (1990) Contributions to the biomechanics of plants. I. Stabilities of plant stems with strengthening elements of different cross‐sections against weight and wind forces. Botanica Acta 103: 111–122.

Strasburger E, Noll F, Schenck H et al. (1903) A Text‐book of Botany. London: Macmillan and Co Ltd.

Stühlen BM (1999) The Mechanical Design of Turgid Plant Tissues (with supplement). Thesis for PhD, University of Reading.

Telewski FW (2006) A unified hypothesis of mechanoperception in plants. American Journal of Botany 93: 1466–1476.

Vincent JFV (1982) The mechanical design of grass. Journal of Materials Science 17: 856–860.

Vincent JFV (1989) The relation between density and stiffness of apple flesh. Journal of the Science of Food and Agriculture 47: 446–432.

Vincent JFV (1991) Strength and fracture of grasses. Journal of Materials Science 26: 1947–1950.

Vincent JFV (2007) Adaptive structures – some biological paradigms. In: Wagg D, Bond IP, Weaver P and Friswell M (eds) Adaptive Structures – Engineering Applications, pp. 261–285. Chichester, UK: Wiley.

Vincent JFV and Jeronimidis G (1992) Mechanical design of fossil plants. In: Rayner JMV and Wootton RM (eds) Biomechanics in Palaeontology, pp. 21–36. Cambridge: The University Press.

Waldron KW, Smith AC, Parr AJ et al. (1997) New approaches to understanding and controlling cell separation in relation to fruit and vegetable texture. Trends in Food Science & Technology 8: 213–221.

Wegst UGK and Ashby MF (2004) The mechanical efficiency of natural materials. Philosophical Magazine 84: 2167–2186.

Weintraub M (1951) Leaf movements in Mimosa pudica L. New Phytologist 50: 357–390.

Whitney SEC, Gothard MGE, Mitchell JT et al. (1999) Roles of cellulose and xyloglucan in determining the mechanical properties of primary plant cell walls. Plant Physiology 121: 657–663.

Further Reading

Fratzl P and Weinkamer R (2007) Nature's hierarchical materials. Progress in Materials Science 52: 1263–1334.

Gibson LJ and Ashby MF (1997) Cellular Solids, Structure and Properties. Cambridge: The University Press.

Gordon JE (1976) The New Science of Strong Materials, or Why you don't fall through the Floor. Harmondsworth: Penguin.

Mattheck C (1998) Design in Nature – Learning from Trees. Heidelberg: Springer.

Prusinkiewicz P and Lindenmayer A (1996) The Algorithmic Beauty of Plants. New York, Berlin, Heidelberg: Springer.

Related Sub-Topics:

Plant Development | Plant Secondary Metabolism | Plant Responses to the Environment | Plant Cell Differentiation | Leaves | Shoots and Buds
Contact Editor close
Submit a note to the editor about this article by filling in the form below.

* Required Field

Article Title: Plant Biomechanics
 
How to Cite close
Vincent, Julian FV(May 2011) Plant Biomechanics. In: eLS. John Wiley & Sons Ltd, Chichester. http://www.els.net [doi: 10.1002/9780470015902.a0002062.pub2]