3D imaging and mechanical modeling of helical buckling in Medicago truncatula plant roots

We study the primary root growth of wild-type Medicago truncatula plants in heterogeneous environments using 3D time-lapse imaging. The growth medium is a transparent hydrogel consisting of a stiff lower layer and a compliant upper layer. We find that the roots deform into a helical shape just above...

Full description

Saved in:
Bibliographic Details
Published inProceedings of the National Academy of Sciences - PNAS Vol. 109; no. 42; pp. 16794 - 16799
Main Authors Silverberg, Jesse L, Noar, Roslyn D, Packer, Michael S, Harrison, Maria J, Henley, Christopher L, Cohen, Itai, Gerbode, Sharon J
Format Journal Article
LanguageEnglish
Published United States National Academy of Sciences 16.10.2012
National Acad Sciences
Subjects
Agricultural soils
Bending
Biomechanical Phenomena
Buckling
culture media
Deformation
Flowers & plants
Gels
Geometry
hydrocolloids
Hydrogel, Polyethylene Glycol Dimethacrylate
Hydrogels
image analysis
Imaging
Mathematical models
Medicago truncatula
Models, Biological
Morphogenesis - physiology
Morphology
Physical Sciences
Plant growth
Plant roots
Plant Roots - anatomy & histology
Plant Roots - growth & development
Plants
Root growth
Root tips
roots
Three dimensional imaging
Online AccessGet full text

Cover

More Information
Summary:We study the primary root growth of wild-type Medicago truncatula plants in heterogeneous environments using 3D time-lapse imaging. The growth medium is a transparent hydrogel consisting of a stiff lower layer and a compliant upper layer. We find that the roots deform into a helical shape just above the gel layer interface before penetrating into the lower layer. This geometry is interpreted as a combination of growth-induced mechanical buckling modulated by the growth medium and a simultaneous twisting near the root tip. We study the helical morphology as the modulus of the upper gel layer is varied and demonstrate that the size of the deformation varies with gel stiffness as expected by a mathematical model based on the theory of buckled rods. Moreover, we show that plant-to-plant variations can be accounted for by biomechanically plausible values of the model parameters.
Bibliography:http://dx.doi.org/10.1073/pnas.1209287109
ObjectType-Article-1
SourceType-Scholarly Journals-1
ObjectType-Feature-2
content type line 23
Author contributions: J.L.S., M.J.H., C.L.H., I.C., and S.J.G. designed research; J.L.S., R.D.N., M.S.P., and S.J.G. performed research; J.L.S., C.L.H., I.C., and S.J.G. analyzed data; and J.L.S., M.J.H., C.L.H., I.C., and S.J.G. wrote the paper.
2Present address: Department of Plant Pathology, North Carolina State University, 2510 Thomas Hall, Raleigh, NC 27695-7616.
Edited by William R. Schowalter, Princeton University, Princeton, NJ, and approved September 5, 2012 (received for review June 4, 2012)
3Present address: Department of Physics, Harvey Mudd College, 301 Platt Blvd., Claremont, CA 91711-5990.
ISSN:0027-8424
1091-6490
DOI:10.1073/pnas.1209287109