Bioelectric patterns in plant tissue regeneration
File(s)
Author(s)
Iredale-Ward, Owen Peter
Type
Thesis
Abstract
This thesis investigates the existence of patterns of cell membrane potential in the distal primary root of Arabidopsis thaliana and their relationship to regeneration frequency. The A. thaliana root tip is capable of regenerating following excision, including reformation of the entire meristem, with the regeneration rate decreasing with the increasing distance of the cut point from the root tip. A protocol is developed for imaging membrane potential patterns in planta using a fluorescent voltage reporter dye, DiBAC4(3), and for analysing the resultant images. The data obtained using this method are used to identify a characteristic pattern of membrane potential in unperturbed roots, consisting of a higher level of depolarisation close to the root tip and a lower level of depolarisation towards the proximal end of the meristem and the transition zone. Membrane potential patterns are compared between intact roots and roots whose tips have been excised, revealing differences in patterns of membrane potential between cut and uncut roots.
Pharmacological perturbation of membrane potential in the root, by means of depolarisation with potassium gluconate and hyperpolarisation with fusicoccin, is found to disrupt patterns of membrane potential in intact roots, with hyperpolarisation making the gradient of membrane potential steeper and depolarisation making it less steep. Hyperpolarisation following cutting is found to correlate with increased regeneration frequency and depolarisation with decreased regeneration frequency. The reasons for this relationship are discussed. Patterns of mitotic activity in the root are imaged following depolarisation and hyperpolarisation treatments.
Exposure of roots to a weak electric field is known to increase regeneration frequency. In order to explore this relationship, patterns of membrane potential are imaged in both cut and uncut roots following exposure to an electric field. No change in membrane potential patterns is found following electric field exposure, and the implications of this finding are discussed.
Pharmacological perturbation of membrane potential in the root, by means of depolarisation with potassium gluconate and hyperpolarisation with fusicoccin, is found to disrupt patterns of membrane potential in intact roots, with hyperpolarisation making the gradient of membrane potential steeper and depolarisation making it less steep. Hyperpolarisation following cutting is found to correlate with increased regeneration frequency and depolarisation with decreased regeneration frequency. The reasons for this relationship are discussed. Patterns of mitotic activity in the root are imaged following depolarisation and hyperpolarisation treatments.
Exposure of roots to a weak electric field is known to increase regeneration frequency. In order to explore this relationship, patterns of membrane potential are imaged in both cut and uncut roots following exposure to an electric field. No change in membrane potential patterns is found following electric field exposure, and the implications of this finding are discussed.
Version
Open Access
Date Issued
2025-12-12
Date Awarded
2026-06-01
Copyright Statement
Attribution-NonCommercial 4.0 International Licence (CC BY-NC)
License URL
Advisor
Sena, Giovanni
Sponsor
Biotechnology and Biological Sciences Research Council (BBSRC)
Publisher Department
Department of Life Sciences
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)