On the role of stress anisotropy in the growth of stems

Journal Article · Sat Aug 03 00:00:00 EDT 2013 · Journal of Experimental Botany

DOI:https://doi.org/10.1093/jxb/ert176· OSTI ID:2483306

Baskin, Tobias I. ^[1]; Jensen, Oliver E. ^[2]

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1. University of Massachusetts, Amherst, MA (United States)
2. University of Manchester (United Kingdom)

We review the role of anisotropic stress in controlling the growth anisotropy of stems. Instead of stress, growth anisotropy is usually considered in terms of compliance. Anisotropic compliance is typical of cell walls, because they contain aligned cellulose microfibrils, and it appears to be sufficient to explain the growth anisotropy of an isolated cell. Nevertheless, a role for anisotropic stress in the growth of stems is indicated by certain growth responses that appear too rapid to be accounted for by changes in cell-wall compliance and because the outer epidermal wall of most growing stems has microfibrils aligned axially, an arrangement that would favour radial expansion based on cell-wall compliance alone. Efforts to quantify stress anisotropy in the stem have found that it is predominantly axial, and large enough in principle to explain the elongation of the epidermis, despite its axial microfibrils. That the epidermis experiences a stress deriving from the inner tissue, the so-called ‘tissue stress’, has been widely recognized; however, the origin of the dominant axial direction remains obscure. Based on geometry, an isolated cylindrical cell should have an intramural stress anisotropy favouring the transverse direction. Explanations for tissue stress have invoked differential elastic moduli, differential plastic deformation (so-called differential growth), and a phenomenon analogous to the maturation stress generated by secondary cell walls. None of these explanations has been validated. Here, we suggest that understanding the role of stress anisotropy in plant growth requires a deeper understanding of the nature of stress in hierarchical, organic structures.

• Research Organization: University of Massachusetts, Amherst, MA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES). Chemical Sciences, Geosciences & Biosciences Division (CSGB)
• Grant/Contract Number: FG02-03ER15421
• OSTI ID: 2483306
• Journal Information: Journal of Experimental Botany, Journal Name: Journal of Experimental Botany Journal Issue: 15 Vol. 64; ISSN 0022-0957
• Publisher: Oxford University Press
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
Cell wall
cellulose microfibril
elongation
growth anisotropy
maturation stress
multiscale model
radial expansion
residual stress
tissue stress
tissue tension