Root Electrical Capacitance Can Be a Promising Plant Phenotyping Parameter in Wheat

Abstract

As root electrical capacitance (CR*) was assumed to depend on the stem properties, the efficiency of measuring CR* at flowering for whole-plant phenotyping was assessed in five wheat cultivars in three replicate plots over two years. Linear regression analysis was used to correlate CR* with plant-size parameters and flag-leaf traits (extension and SPAD chlorophyll content) at flowering, and with yield components at maturity. The plot-mean CR* was correlated with the plot leaf area index (LAI), the chlorophyll quantity (LAI×SPAD), and the grain yield across years. At plant scale, CR* was found to show the strongest positive regression with total chlorophyll in the flag leaf (flag leaf area × SPAD; R2: 0.65–0.74) and with grain mass (R2: 0.55–0.70) for each cultivar and year (p < 0.001). Likewise, at plot scale, the regression was strongest between CR* and the LAI×SPAD value (R2: 0.86–0.99; p < 0.01) for the cultivars. Consequently, CR* indicated the total plant nutrient and photosynthate supply at flowering, which depended on root uptake capacity, and strongly influenced the final yield. Our results suggested that the polarization of the active root membrane surfaces was the main contributor to CR*, and that the measurement could be suitable for evaluating root size and functional intensity. In conclusion, the capacitance method can be applied for nondestructive whole-plant phenotyping, with potential to estimate root and shoot traits linked to the nutrient supply, and to predict grain yield. CR* can be incorporated into allometric models of cereal development, contributing to optimal crop management and genetic improvement.

Plant impedance spectroscopy: a review of modeling approaches and applications

“…Ozier-Lafontaine and Bajazet (2005) established strong correlations between the capacitance of root tissue and the (wet and dry) weight of the root system. The EIS method has demonstrated its potential to indirectly assess and monitor the root biomass, morphological indices (Cao et al, 2011), and environmental stressors, including cadmium pollution, (Mancuso, 2000) quick, easy and nondestructive non-robust capacitance measurements water uptake (Afzal et al, 2017;Cseresnyeś et al, 2022), biomass (Dietrich et al, 2013;Cseresnyeś et al, 2018) in situ, fast, non-invasive environment-sensitive resistivity tomography biomass (Paglis, 2013) (Repo et al, 2014), and weed competition. Liu et al (2021a) recently conducted an in-depth review of progress and developments in applying EIS to plant roots.…”