Modeling Plant Roots Spectral Induced Polarization Signature

Abstract

Monitoring the growth, architecture, and function of plant roots is of great interest. One promising noninvasive geoelectrical monitoring approach is spectral induced polarization (SIP). However, the roots' SIP signature is underexplored, not well understood, and a mechanistic model has not been proposed. Here, we developed a mechanistic model for SIP's response of roots, which is based on the Poisson‐Nernst‐Planck equation. The modeling results suggest that the magnitude of root polarization is linearly related to the root's external surface area and that the polarization length scale is the root's diameter. We suggest that injecting a current to the plant's stem results in higher polarization associated with the root‐cells' total surface area. In this case, the polarization length scale is the cell diameter. Overall, we quantified the link between the root's dimensions and their electrical signature, which may inspire SIP application for root phenotyping.

Combining Models of Root-Zone Hydrology and Geoelectrical Measurements: Recent Advances and Future Prospects

“…This impact can be direct and indirect. The former derives from the direct rootcurrent iteration and depends on the large surface area and capacitance of roots, which, in turns, has been linked to root physiology and suberization (Weigand, 2017;Peruzzo et al, 2021;Tsukanov and Schwartz, 2021). The latter, indirect impact, is a combination of the root-induced changes in the physical, chemical, and biological properties of the rhizosphere, e.g., RWU, root exudation, solute uptake and rhizosphere microbiome changes (Landl et al, 2021).…”

High frequency soil polarization can phenotype crop roots noninvasively

“…EC is the amount of charge stored in a capacitor under a certain voltage. Generally, the electrical methods such as EC can be divided into stem-based (root EC (EC root ), one electrode is located on the stem and the other one is in the medium) measurement and medium-based (medium capacitance, both electrodes are located in the medium) measurement (Tsukanov and Schwartz, 2021).…”

“…in the medium) measurement and medium-based (medium capacitance, both electrodes are located in the medium) measurement (Tsukanov and Schwartz, 2021).…”

Pore-Scale Mechanisms for Spectral Induced Polarization of Calcite Precipitation Inferred from Geo-Electrical Millifluidics

“…Geophysical methods allow for noninvasive imaging of the subsurface with higher spatial and temporal resolution. Spectral induced polarization (SIP) has shown potential to detect biogeochemical processes, − including calcite precipitation, in laboratory − and field measurements. , SIP measures the voltage between selected positions in the geological material while injecting a sinusoidal current in the mHz to kHz frequency range. , Due to an external electric field, the charges in the material accumulate under geometric constraints (induced polarization). , The main purpose of an SIP measurement is to detect this process. For this, the measured voltage is processed to obtain the phase shift between the applied current and the measured voltage φ, the magnitude of the electrical conductivity |σ|, and finally the complex conductivity σ*: In the absence of a conductive solid phase, the real part of the conductivity (σ′) results from the electrolytic conduction in the water-filled pore space and along solid surfaces, whereas the imaginary part of the conductivity (σ″) corresponds to the induced polarization.…”

“…Geophysical methods allow for non-invasive imaging of the subsurface with higher spatial and temporal resolution. Spectral induced polarization (SIP) has shown potential to detect biogeochemical processes [10][11][12][13][14] , including calcite precipitation, in laboratory [15][16][17][18] and field measurements 19,20 . SIP measures the voltage between selected positions in the geological material while injecting a sinusoidal current in the mHz to kHz frequency range 21,22 .…”