Axial and Radial Hydraulic Resistance to Roots of Maize (<i>Zea mays</i> L.)

Frensch, Jürgen; Steudle, Ernst

doi:10.1104/pp.91.2.719

Cited by 287 publications

(283 citation statements)

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“…For most species, hydraulic conductivity is higher in the younger, distal region of the root than in the proximal region, despite the immaturity of the xylem near the root apex (Frensch & Steudle, 1989 ;North & Nobel, 1992). Thus, a capacity for rapid root growth upon the cessation of drought due to the elongation of existing roots and\or the production of new lateral roots can enhance water uptake (Nobel & Sanderson, 1984).…”

Section: mentioning

confidence: 99%

Root growth, developmental changes in the apex, and hydraulic conductivity for Opuntia ficus‐indica during drought

Dubrovsky¹,

North

Nobel

1998

New Phytologist

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Developmental changes in the root apex and accompanying changes in lateral root growth and root hydraulic conductivity were examined for Opuntia ficus-indica (L.) Miller during rapid drying, as occurs for roots near the soil surface, and more gradual drying, as occurs in deeper soil layers. During 7 d of rapid drying (in containers with a 3-cm depth of vermiculite), the rate of root growth decreased sharply and most root apices died ; such a determinate pattern of root growth was not due to meristem exhaustion but rather to meristem mortality after 3 d of drying. The length of the meristem, the duration of the cell division cycle, and the length of the elongation zone were unchanged during rapid drying. During 14 d of gradual drying (in containers with a 6-cm depth of vermiculite), root mortality was relatively low ; the length of the elongation zone decreased by 70 %, the number of meristematic cells decreased 30 %, and the duration of the cell cycle increased by 36 %. Root hydraulic conductivity (L P ) decreased to one half during both drying treatments ; L P was restored by 2 d of rewetting owing to the emergence of lateral roots following rapid drying and to renewed apical elongation following gradual drying. Thus, in response to drought, the apical meristems of roots of O. ficus-indica near the surface die, whereas deeper in the substrate cell division and elongation in root apices continue. Water uptake in response to rainfall in the field can be enhanced by lateral root proliferation near the soil surface and additionally by resumption of apical growth for deeper roots.

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Section: mentioning

confidence: 99%

Root growth, developmental changes in the apex, and hydraulic conductivity for Opuntia ficus‐indica during drought

Dubrovsky¹,

North

Nobel

1998

New Phytologist

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“…The model for the composite root derived by Chen (2016) assumes the existence of a hydraulic dead zone close to the tip of the root. As explained in the work of Chen (2016), this is based on the findings of Frensch & Steudle (1989), who experimentally found that the axial conductivity of the xylem decreases from a constant value to zero within a short distance to the tip. The cone-shaped tip region requires the radius of all xylem vessels to shrink to zero in the region.…”

Section: Physical Justification Of the Cylindrical Area Approximationmentioning

confidence: 99%

Minimizing hydraulic resistance of a plant root by shape optimization

Chandrashekar

Chen

2016

Mechanics Research Communications

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Analytical solution of the pressure field for water uptake through a composite root, coupled with fully saturated soil is derived by using the slender body approximation. It is shown that in general, the resistance of the root and soil are not additive. This result can play a very important role in modelling water uptake through plant roots and determination of hydraulic resistances of plant roots. Optimum plant root structure that minimizes a single root's hydraulic resistance is also studied in this work with the constraint of prescribed root volume. Hydraulic resistances under the slender body approximation and without such a limitation are considered. It is found that for large stele-to-cortex permeability ratio, there exists an optimum root length-to-base-radius ratio that minimizes the hydraulic resistance.A remarkable feature of the optimum root structure is that the optimum dimensionless stele conductivity depends only on a single geometrical parameter, the stele-to-root base-radius ratio. Once the stele-to-root base-radius ratio and the stele-to-cortex permeability ratio are given, the optimum root length-to-radius ratio can be found. While these findings remain to be verified by experiments for real plant roots, they offer theoretical guidance for the design of bio-inspired structures that minimizes hydraulic resistance for fluid production from porous media.ii ACKNOWLEDGMENTS I would like to sincerely thank Dr. Chen, my thesis advisor, for the encouragement and support that he has provided at every step and for being a great teacher.

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“…It is generally accepted that the axial flow along the xylem is governed by Poiseuille's law (Frensch & Steudle, 1989) such that the dimensional axial flux (m 3 s 1 ) is given bŷ…”

Section: Water Transport In the Xylemmentioning

confidence: 99%

A Mathematical Model of Water and Nutrient Transport in Xylem Vessels of a Wheat Plant

et al. 2014

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At a time of increasing global demand for food, dwindling land and resources, and escalating pressures from climate change, the farming industry is undergoing financial strain, with a need to improve e ciency and crop yields. In order to improve e ciencies in farming, and in fertiliser usage in particular, understanding must be gained of the fertiliser-to-crop-yield pathway. We model one aspect of this pathway; the transport of nutrients within the vascular tissues of a crop plant from roots to leaves. We present a mathematical model of the transport of nutrients within the xylem vessels in response to the evapotranspiration of water. We determine 7 di↵erent classes of flow, including positive unidirectional flow, which is optimal for nutrient transport from the roots to the leaves; and root multidirectional flow, which is similar to the hydraulic lift process observed in plants. We also investigate the e↵ect of di↵usion on nutrient transport and find that di↵usion can be significant at the vessel termini especially if there is an axial e✏ux of nutrient, and at night when transpiration is minimal. Models such as these can then be coupled to whole-plant models to be used for optimisation of nutrient delivery scenarios.

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Axial and Radial Hydraulic Resistance to Roots of Maize (Zea mays L.)

Cited by 287 publications

References 20 publications

Root growth, developmental changes in the apex, and hydraulic conductivity for Opuntia ficus‐indica during drought

Root growth, developmental changes in the apex, and hydraulic conductivity for Opuntia ficus‐indica during drought

Minimizing hydraulic resistance of a plant root by shape optimization

A Mathematical Model of Water and Nutrient Transport in Xylem Vessels of a Wheat Plant

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