Physics Commons^™

3d Imaging And Mechanical Modeling Of Helical Buckling In Medicago Truncatula Plant Roots, Jesse L. Silverberg, Roslyn D. Noar, Michael S. Packer, Maria J. Harrison, Christopher L. Henley, Itai Cohen, Sharon J. Gerbode

All HMC Faculty Publications and Research

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 …