Evelyne Kolb

Internship proposal for 2018_2018

Plant roots interacting with mechanical obstacles mimicking a granular soil

see the link Internship Proposal_ROOTS_2018_2019_WEBSite

During this internship we propose to study the growth pattern and forces developed by a root interacting with (i) a single obstacle of known stiffness or (ii) an assembly of obstacles in hydroponics. Temporal evolution of force and growth rate will be determined to identify the different critical times for biological feedbacks in the case of a root growing against a single obstacle and to determine for which conditions the root buckles. In the case of multiple root-obstacle interactions, we will focus on the spatio-temporal evolution of growth. Posts of different shapes in random or regular networks with different spacing will be used to trigger the reorientation of root growth if not stopped. The rigidities of the posts will be adjusted by choosing different materials like plexiglass, 3D-printing material or PDMS and using techniques developed in microfluidics. By time-lapse photography and image analysis, the pattern of growth will provide information about the competing mechanisms of root growth reorientation due to the presence of obstacle or due to gravitropism.

Chick-pea root growing in hydroponics in an assembly of circular posts of PDMS  ( top left) or 3D-printing polymer arrays of baffles (bottom left:design;  right panel: experiment)