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Plant root growth against a mechanical obstacle: The early growth response of a maize root facing an axial resistance is consistent with the Lockhart model

Citation

Kolb, Evelyne; Quiros, Manon; Bogeat-Triboulot, Marie-Béatrice; Couturier, Etienne (2022), Plant root growth against a mechanical obstacle: The early growth response of a maize root facing an axial resistance is consistent with the Lockhart model, Dryad, Dataset, https://doi.org/10.5061/dryad.47d7wm3h1

Abstract

Plant root growth is dramatically reduced in compacted soils, affecting the growth of the whole plant. Through a model experiment coupling force and kinematics measurements, we probed the force-growth relationship of a primary root contacting a stiff resisting obstacle, that mimics the strongest soil impedance variation encountered by a growing root. The growth of maize roots just emerging from a corseting agarose gel and contacting a force sensor (acting as an obstacle) was monitored by time-lapse imaging simultaneously to the force.

The evolution of the velocity field along the root was obtained from kinematics analysis of the root texture with a PIV derived-technique. A triangular fit was introduced to retrieve the elemental elongation rate or strain rate. A parameter-free model based on the Lockhart law quantitatively predicts how the force at the obstacle modifies several features of the growth distribution (length of the growth zone, maximal elemental elongation rate, velocity) during the first 10 minutes. These results suggest a strong similarity of the early growth responses elicited either by a directional stress (contact) or by an isotropic perturbation (hyperosmotic bath).

Methods

Images were obtained with a CCD camera (Nikon, D5200 with Infra-Red absorbing filter removed with a Nikkor 60 mm macro-lens), cropped with ImageJ and analysed with Kymorod,a Matlab applet developped by Bastien et al, Plant Journal, 2016.

Voltage data were collected with a Futek LSB200 force sensor and calibration of the sensor provides force data.

Usage Notes

Any pdf viewer and text editors

ImageJ (https://imagej.nih.gov/ij/download.html) for images and movies

Funding

Centre National pour la Recherche Scientifique et Technique

Sorbonne Université

Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement

Universite Paris Cité

École Supérieure de Physique et de Chimie Industrielles de la Ville de Paris