Measuring Root Hydraulic Parameters of Container-grown Herbaceous and Woody Plants Using the Hydraulic Conductance Flow Meter

Abstract

<jats:p>Root hydraulic conductance and conductivity are physiological traits describing the ease with which water can move through the belowground vascular system of a plant, and are used as indicators of plant performance and adaptability to a given environment. The ability to measure hydraulic conductance of container-grown herbaceous and semiwoody plants with soft conductive tissue was tested using a hydraulic conductance flow meter (HCFM). Although the HCFM is a hydraulic apparatus that has been used on woody plants to measure hydraulic conductance of intact roots, it has never been reportedly used on container-grown horticultural plants. Two herbaceous species, <jats:italic>Chrysanthemum</jats:italic> L. and <jats:italic>Solenstemon scutellarioides</jats:italic> Thonn., were grown in containers and hydraulic parameters were measured, including root conductance and root conductivity, as well as physical traits such as stem diameter and dry root mass. The HCFM was easily connected to intact roots even on herbaceous stems and was used to determine hydraulic conductance and conductivity directly on container-grown plants with minimal disturbance on the root system. Chrysanthemums, <jats:italic>Buddleja davidii</jats:italic> Franch., and <jats:italic>Hibiscus moscheutos</jats:italic> L. were grown in three different substrates, and both root mass and root hydraulic parameters were determined. Chrysanthemums showed a positive response with increasing root hydraulic conductance with increasing root mass. The substrates used in these studies only had an effect on root biomass of chrysanthemums, but substrates had no differential effect on root hydraulic conductivity.</jats:p>

Root hydraulic phenotypes impacting water uptake in drying soils

“…The maximum root hydraulic conductance, K root_max , is defined as the slope of E ( ψ leaf_x ) in wet soils. K root_max was soil texture independent and hence was positively related to root length across species and textures (Figure 3a ), which was in line with Maurel et al ( 2010 ) and Judd et al ( 2016 ). For cereals, K root_max of maize in sand and loam, barley in sandy loam, and millet was similar.…”

Parameterization of Root Water Uptake Models Considering Dynamic Root Distributions and Water Uptake Compensation

“…The root system hydraulic conductance, K rs , can also be measured directly in the laboratory or in field experiments by a high‐pressure flow meter (Judd et al, 2016; Tyree et al, 1995) or a pressure chamber (Miyamoto et al, 2001). However, these measurements were restricted to extracted root systems and, for crops, the measurements were mostly performed on young roots of seedlings.…”

Aquaporin regulation in roots controls plant hydraulic conductance, stomatal conductance, and leaf water potential in Pinus radiata under water stress

“…The applied pressure was increased gradually from 0 to approximately 300 KPa over the course of approximately 1 min and the flow rate logged every 2 s using the Dynamax software. Flow rates measured at increasing pressure are less vulnerable to flow rate reductions caused by the plant's wound response than flow rates measured at constant pressure (Judd, Jackson, Fonteno, & Domec, ; Li & Liu, ; Tyree et al, ). Once the transient curve was constructed, hydraulic conductance ( K ) was calculated using the formula: K = Q v / P ; where Q v is the volumetric flow rate (kg s −1 ) and P is the applied pressure (MPa).…”