Root elongation, water stress, and mechanical impedance: a review of limiting stresses and beneficial root tip traits

A. Glyn Bengough, B. M. McKenzie, P. D. Hallett, T. A. Valentine

    Research output: Contribution to journalReview article

    330 Citations (Scopus)

    Abstract

    Root elongation in drying soil is generally limited by a combination of mechanical impedance and water stress. Relationships between root elongation rate, water stress (matric potential), and mechanical impedance (penetration resistance) are reviewed, detailing the interactions between these closely related stresses. Root elongation is typically halved in repacked soils with penetrometer resistances > 0.8-2 MPa, in the absence of water stress. Root elongation is halved by matric potentials drier than about -0.5 MPa in the absence of mechanical impedance. The likelihood of each stress limiting root elongation is discussed in relation to the soil strength characteristics of arable soils. A survey of 19 soils, with textures ranging from loamy sand to silty clay loam, found that similar to 10% of penetration resistances were > 2 MPa at a matric potential of -10 kPa, rising to nearly 50% > 2 MPa at - 200 kPa. This suggests that mechanical impedance is often a major limitation to root elongation in these soils even under moderately wet conditions, and is important to consider in breeding programmes for drought-resistant crops. Root tip traits that may improve root penetration are considered with respect to overcoming the external (soil) and internal (cell wall) pressures resisting elongation. The potential role of root hairs in mechanically anchoring root tips is considered theoretically, and is judged particularly relevant to roots growing in biopores or from a loose seed bed into a compacted layer of soil.

    Original languageEnglish
    Pages (from-to)59-68
    Number of pages10
    JournalJournal of Experimental Botany
    Volume62
    Issue number1
    DOIs
    Publication statusPublished - Jan 2011

    Keywords

    • Root growth
    • soil compaction
    • soil strength
    • water potential
    • MAIZE ZEA-MAYS
    • SOIL STRENGTH
    • PENETRATION RESISTANCE
    • SEEDLING ROOTS
    • PLANT-ROOTS
    • PENETROMETER RESISTANCE
    • FRICTIONAL RESISTANCE
    • ARABIDOPSIS-THALIANA
    • GROWTH PRESSURE
    • SEMINAL ROOTS

    Cite this

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    title = "Root elongation, water stress, and mechanical impedance: a review of limiting stresses and beneficial root tip traits",
    abstract = "Root elongation in drying soil is generally limited by a combination of mechanical impedance and water stress. Relationships between root elongation rate, water stress (matric potential), and mechanical impedance (penetration resistance) are reviewed, detailing the interactions between these closely related stresses. Root elongation is typically halved in repacked soils with penetrometer resistances > 0.8-2 MPa, in the absence of water stress. Root elongation is halved by matric potentials drier than about -0.5 MPa in the absence of mechanical impedance. The likelihood of each stress limiting root elongation is discussed in relation to the soil strength characteristics of arable soils. A survey of 19 soils, with textures ranging from loamy sand to silty clay loam, found that similar to 10{\%} of penetration resistances were > 2 MPa at a matric potential of -10 kPa, rising to nearly 50{\%} > 2 MPa at - 200 kPa. This suggests that mechanical impedance is often a major limitation to root elongation in these soils even under moderately wet conditions, and is important to consider in breeding programmes for drought-resistant crops. Root tip traits that may improve root penetration are considered with respect to overcoming the external (soil) and internal (cell wall) pressures resisting elongation. The potential role of root hairs in mechanically anchoring root tips is considered theoretically, and is judged particularly relevant to roots growing in biopores or from a loose seed bed into a compacted layer of soil.",
    keywords = "Root growth, soil compaction, soil strength, water potential, MAIZE ZEA-MAYS, SOIL STRENGTH, PENETRATION RESISTANCE, SEEDLING ROOTS, PLANT-ROOTS, PENETROMETER RESISTANCE, FRICTIONAL RESISTANCE, ARABIDOPSIS-THALIANA, GROWTH PRESSURE, SEMINAL ROOTS",
    author = "Bengough, {A. Glyn} and McKenzie, {B. M.} and Hallett, {P. D.} and Valentine, {T. A.}",
    year = "2011",
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    doi = "10.1093/jxb/erq350",
    language = "English",
    volume = "62",
    pages = "59--68",
    journal = "Journal of Experimental Botany",
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    publisher = "Oxford University Press",
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    }

    Root elongation, water stress, and mechanical impedance: a review of limiting stresses and beneficial root tip traits. / Bengough, A. Glyn; McKenzie, B. M.; Hallett, P. D.; Valentine, T. A.

    In: Journal of Experimental Botany, Vol. 62, No. 1, 01.2011, p. 59-68.

    Research output: Contribution to journalReview article

    TY - JOUR

    T1 - Root elongation, water stress, and mechanical impedance: a review of limiting stresses and beneficial root tip traits

    AU - Bengough, A. Glyn

    AU - McKenzie, B. M.

    AU - Hallett, P. D.

    AU - Valentine, T. A.

    PY - 2011/1

    Y1 - 2011/1

    N2 - Root elongation in drying soil is generally limited by a combination of mechanical impedance and water stress. Relationships between root elongation rate, water stress (matric potential), and mechanical impedance (penetration resistance) are reviewed, detailing the interactions between these closely related stresses. Root elongation is typically halved in repacked soils with penetrometer resistances > 0.8-2 MPa, in the absence of water stress. Root elongation is halved by matric potentials drier than about -0.5 MPa in the absence of mechanical impedance. The likelihood of each stress limiting root elongation is discussed in relation to the soil strength characteristics of arable soils. A survey of 19 soils, with textures ranging from loamy sand to silty clay loam, found that similar to 10% of penetration resistances were > 2 MPa at a matric potential of -10 kPa, rising to nearly 50% > 2 MPa at - 200 kPa. This suggests that mechanical impedance is often a major limitation to root elongation in these soils even under moderately wet conditions, and is important to consider in breeding programmes for drought-resistant crops. Root tip traits that may improve root penetration are considered with respect to overcoming the external (soil) and internal (cell wall) pressures resisting elongation. The potential role of root hairs in mechanically anchoring root tips is considered theoretically, and is judged particularly relevant to roots growing in biopores or from a loose seed bed into a compacted layer of soil.

    AB - Root elongation in drying soil is generally limited by a combination of mechanical impedance and water stress. Relationships between root elongation rate, water stress (matric potential), and mechanical impedance (penetration resistance) are reviewed, detailing the interactions between these closely related stresses. Root elongation is typically halved in repacked soils with penetrometer resistances > 0.8-2 MPa, in the absence of water stress. Root elongation is halved by matric potentials drier than about -0.5 MPa in the absence of mechanical impedance. The likelihood of each stress limiting root elongation is discussed in relation to the soil strength characteristics of arable soils. A survey of 19 soils, with textures ranging from loamy sand to silty clay loam, found that similar to 10% of penetration resistances were > 2 MPa at a matric potential of -10 kPa, rising to nearly 50% > 2 MPa at - 200 kPa. This suggests that mechanical impedance is often a major limitation to root elongation in these soils even under moderately wet conditions, and is important to consider in breeding programmes for drought-resistant crops. Root tip traits that may improve root penetration are considered with respect to overcoming the external (soil) and internal (cell wall) pressures resisting elongation. The potential role of root hairs in mechanically anchoring root tips is considered theoretically, and is judged particularly relevant to roots growing in biopores or from a loose seed bed into a compacted layer of soil.

    KW - Root growth

    KW - soil compaction

    KW - soil strength

    KW - water potential

    KW - MAIZE ZEA-MAYS

    KW - SOIL STRENGTH

    KW - PENETRATION RESISTANCE

    KW - SEEDLING ROOTS

    KW - PLANT-ROOTS

    KW - PENETROMETER RESISTANCE

    KW - FRICTIONAL RESISTANCE

    KW - ARABIDOPSIS-THALIANA

    KW - GROWTH PRESSURE

    KW - SEMINAL ROOTS

    U2 - 10.1093/jxb/erq350

    DO - 10.1093/jxb/erq350

    M3 - Review article

    VL - 62

    SP - 59

    EP - 68

    JO - Journal of Experimental Botany

    JF - Journal of Experimental Botany

    SN - 0022-0957

    IS - 1

    ER -