ORCID Profile
0000-0003-2651-3915
Current Organisation
University of South Australia
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Publisher: Elsevier BV
Date: 11-2013
DOI: 10.1016/J.JTBI.2013.07.025
Abstract: In this paper, we present and discuss a mathematical model of ion uptake and transport in roots of plants. The underlying physical model of transport is based on the mechanisms of forced diffusion and convection. The model can take account of local variations in effective ion and water permeabilities across the major tissue regions of plant roots, represented through a discretized coupled system of governing equations including mass balance, forced diffusion, convection and electric potential. We present simulation results of an exploration of the consequent enormous parameter space. Among our findings we identify the electric potential as a major factor affecting ion transport across, and accumulation in, root tissues. We also find that under conditions of a constant but realistic level of bulk soil salt concentration and plant-soil hydraulic pressure, diffusion plays a significant role even when convection by the water transpiration stream is operating.
Publisher: Frontiers Media SA
Date: 28-07-2017
Publisher: Elsevier BV
Date: 11-2015
DOI: 10.1016/J.JTBI.2015.08.024
Abstract: We present and explore a kinetic model of ion transport across and between the membranes of an isolated plant cell with an emphasis on the cell's response to salt (Na(+)) stress. The vacuole, cytoplasm and apoplast are treated as concentric regions separated by tonoplast and plasma membranes. The model includes the transport of Na(+), K(+), Cl(-) and H(+) across both membranes via primary active proton pumps, secondary active antiporters and symporters, as well as passive ion channels. In addition, water transport is included, allowing us to investigate both the osmotic and ionic components of salt stress. The model's predictions of steady state and transient cytosolic pH and Na(+) concentrations were found to be quantitatively comparable to measured experimental values. Through an extensive simulation study we have identified and characterized scenarios in which in idual transport processes (H(+) pumps, Na(+)/H(+) antiporters and channels involved in the transport of Na(+)) and their combinations have major effects on the level of Na(+) in each of the cell compartments. This systematic study emulates the effects of overexpressing and inhibiting transporter genes by genetic modification and hence we have compared our simulations with observations from experiments conducted on transgenic plants. The simulations suggest that overexpressing tonoplast Na(+)/H(+) antiporter genes and tonoplast H(+) pump genes lead to an increase in the storage of Na(+) in the vacuole (helping the cell to maintain water uptake under salt stress), with only a transient influence on the cytoplasmic Na(+) concentration. The model predicts effects of varying the expression of transporter genes (in idually or in combination) which have yet to be investigated in experiments. For ex le, our findings indicate that simultaneously overexpressing plasma membrane and tonoplast Na(+)/H(+) antiporter genes would lead to improvements in both ionic and osmotic stress tolerance. The results demonstrate the importance of simultaneously modelling the transport of Na(+) across both the tonoplast and plasma membrane, a task not undertaken previously.
Publisher: Elsevier BV
Date: 2014
DOI: 10.1016/J.JTBI.2013.09.004
Abstract: We simulate the competitive uptake and transport of a mixed salt system in the differentiated tissues of plant roots. The results are based on a physical model that includes both forced diffusion and convection by the transpiration stream. The influence of the Casparian strip on regulating apoplastic flow, the focus of the paper, is modelled by varying ion diffusive permeabilities, hydraulic reflection coefficients and water permeability for transport across the endodermis-pericycle interface. We find that reducing diffusive permeabilities leads to significantly altered ion concentration profiles in the pericycle and vascular cylinder regions, while increased convective reflectivities affect predominantly ion concentrations in the cortex and endodermis tissues. The self-consistent electric field arising from ion separation is a major influence on predicted ion fluxes and accumulation rates.
Publisher: Wiley
Date: 29-08-2020
DOI: 10.1111/NPH.15955
Abstract: Plants are inherently dynamic. Dynamics minimize stress while enabling plants to flexibly acquire resources. Three ex les are presented for plants tolerating saline soil: transport of sodium chloride (NaCl), water and macronutrients is nonuniform along a branched root water and NaCl redistribute between shoot and soil at night-time and ATP for salt exclusion is much lower in thinner branch roots than main roots, quantified using a biophysical model and geometry from anatomy. Noninvasive phenotyping and precision agriculture technologies can be used together to harness plant dynamics, but analytical methods are needed. A plant advancing in time through a soil and atmosphere space is proposed as a framework for dynamic data and their relationship to crop improvement.
Publisher: Frontiers Media SA
Date: 23-06-2016
Publisher: Frontiers Media SA
Date: 18-09-2019
Publisher: Wiley
Date: 11-07-2019
DOI: 10.1111/NPH.15864
Abstract: Agriculture is expanding into regions that are affected by salinity. This review considers the energetic costs of salinity tolerance in crop plants and provides a framework for a quantitative assessment of costs. Different sources of energy, and modifications of root system architecture that would maximize water vs ion uptake are addressed. Energy requirements for transport of salt (NaCl) to leaf vacuoles for osmotic adjustment could be small if there are no substantial leaks back across plasma membrane and tonoplast in root and leaf. The coupling ratio of the H
Publisher: Wiley
Date: 29-11-2019
DOI: 10.1111/NPH.15555
No related grants have been discovered for Kylie Foster.