Root Tip Shape Governs Root Elongation Rate under Increased Soil Strength

Colombi, Tino; Kirchgeßner, Norbert; Walter, Achim; Keller, Thomas

doi:10.1104/pp.17.00357

Cited by 92 publications

(100 citation statements)

References 44 publications

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“…An interesting question is whether lateral roots in biopores premeditatedly grow toward the bulk soil to gain better access to water and nutrient resources. Such feedforward mechanisms, where plants are able to "sense" their physical environment, have been observed in several studies (e.g., Colombi et al, 2017;Passioura, 2002;Stirzaker et al, 1996).…”

Section: Modeling Root Growth In Soil With Bioporesmentioning

confidence: 76%

“…Legumes were shown to be more sensitive to soil compaction than cereals (Arvidsson and Håkansson, 2014), and soybean [ Glycine max (L.) Merr. ], maize, and barley roots were observed to colonize biopores more frequently than wheat roots when grown on the same field site (Colombi et al, 2017; Perkons et al, 2014). The significance of biopores as root growth pathways to greater soil depths may thus be even higher for plants other than wheat.…”

Section: Discussionmentioning

confidence: 99%

“…Laboratory experiments (e.g., Hirth et al, 2005; Stirzaker et al, 1996) can give valuable information on the influence of soil structure on both root growth and root water uptake but are limited to young plants, small pot sizes, and short measurement intervals. Field experiments (e.g., Colombi et al, 2017; Kautz et al, 2013; White and Kirkegaard, 2010) provide important insights on the dynamics of root growth in soils with biopores during entire cropping periods but do not allow direct investigation of the influence of soil structure on root water uptake. Simulation models can thereby help to explain the relations among experimental data (e.g., link water use efficiency with soil water content and bioporosity) and to test scenarios of different environmental and soil physical conditions.…”

mentioning

confidence: 99%

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Modeling the Impact of Biopores on Root Growth and Root Water Uptake

Landl

Schnepf

Uteau³

et al. 2019

Vadose Zone Journal

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Core Ideas A 3D soil–root model was used to investigate root–biopore interactions. Known effects of biopores on root growth, i.e., increased root length and depth were reproduced. Despite reducing root–soil contact, biopores led to increased water uptake in dry periods. Biopores had a larger impact on water uptake for more compact and less conductive soils. Roots are known to use biopores as preferential growth pathways to overcome hard soil layers and access subsoil water resources. This study evaluates root–biopore interactions at the root‐system scale under different soil physical and environmental conditions using a mechanistic simulation model and extensive experimental field data. In a field experiment, spring wheat (Triticum aestivum L.) was grown on silt loam with a large biopore density. X‐ray computed tomography scans of soil columns from the field site were used to provide a realistic biopore network as input for the three‐dimensional numerical R‐SWMS model, which was then applied to simulate root architecture as well as water flow in the root–biopore–soil continuum. The model was calibrated against observed root length densities in both the bulk soil and biopores by optimizing root growth model input parameters. By implementing known interactions between root growth and soil penetration resistance into our model, we could simulate root systems whose response to biopores in the soil corresponded well to experimental observations described in the literature, such as increased total root length and increased rooting depth. For all considered soil physical (soil texture and bulk density) and environmental conditions (years of varying dryness), we found biopores to substantially mitigate transpiration deficits in times of drought by allowing roots to take up water from wetter and deeper soil layers. This was even the case when assuming reduced root water uptake in biopores due to limited root–soil contact. The beneficial impact of biopores on root water uptake was larger for more compact and less conductive soils.

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Section: Modeling Root Growth In Soil With Bioporesmentioning

confidence: 76%

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

See 1 more Smart Citation

Modeling the Impact of Biopores on Root Growth and Root Water Uptake

Landl

Schnepf

Uteau³

et al. 2019

Vadose Zone Journal

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“…Based on previous studies (Vollsnes et al ., 2010; Ruiz et al ., 2016; Colombi et al ., 2017 b ), we hypothesized that root cap shape influenced root penetration ability and root response to medium strength by changing the distribution of mechanical stresses resulting from the axially-oriented external force. It has been suggested that a pointed root tip increased axial stresses at the tip forefront rather than around the tip, resulting in enhanced crack initiation and enhanced penetration ability (Colombi et al ., 2017 b ). In our experiments, contrary to this hypothesis, fez-2 roots, that showed acute tips, exhibited reduced penetration abilities whereas smb-3 roots, that showed dome-shaped tips, exhibited enhanced penetration abilities compared to wild-type roots.…”

Section: Discussionmentioning

confidence: 99%

“…In accordance with Euler’s law, species with a higher increase in root diameter in response to medium strength are more efficient in penetrating strong layers (Materechera et al ., 1992). Besides root diameter and growth zone length, it has been shown that root tip shape was also an important feature modulating root responses to medium strength (Ruiz et al ., 2016; Colombi et al ., 2017 b ). In compacted soils, root tips with an acute opening angle grow faster than root tips with a blunted geometry (Iijima et al ., 2003 a , b ; Colombi et al ., 2017 b ).…”

Section: Introductionmentioning

confidence: 99%

The cap size and shape of Arabidopsis thaliana primary roots impact the root responses to an increase in medium strength

Roue

Chauvet

Brunel-Michac

et al. 2018

Preprint

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During root progression in soil, root cap cells are the first to encounter obstacles. The root cap is known to sense environmental cues, making it a relevant candidate for a mechanosensing site. An original two-layer medium was developed in order to study root responses to growth medium strength and the importance of the root cap in the establishment of these responses. Root growth and trajectory of primary roots of Arabidopsis thaliana seedlings were investigated using in vivo image analysis. After contact with the harder layer, the root either penetrated it or underwent rapid curvature, enabling reorientation of the root primary growth. The role of the root cap in tip reorientation was investigated by analyzing the responses of Arabidopsis mutant roots with altered caps. The primary root of fez-2 mutant lines, which has fewer root cap cell layers than wild-type roots, showed impaired penetration ability. Conversely, smb-3 roots of mutant lines, which display a higher number of root cap cells, showed enhanced penetration abilities. This work highlights that alterations in root cap shape and size affect the root responses to medium strength.HighlightThe analysis of the growth and orientation of Arabidopsis thaliana mutant roots affected in root cap size and shape showed that properly formed root cap is required to trigger the root responses to medium strength.AbbreviationsCOLcolumella;LRCLateral Root Cap;SISharpness Index;SMBSOMBRERO.

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