Plant exudates may stabilize or weaken soil depending on species, origin and time

Effect of plant exudates on rhizosphere formation

M. Naveed, L.K. Brown, A.C. Raffan, T.S. George, A.G. Bengough, T. Roose, I. Sinclair, N. Koebernick, L. Cooper, C.A. Hackett

Research output: Contribution to journalArticle

Abstract

We hypothesized that plant exudates could either gel or disperse soil depending on their chemical characteristics. Barley (Hordeum vulgare L. cv. Optic) and maize (Zea mays L. cv. Freya) root exudates were collected using an aerated hydroponic method and compared with chia (Salvia hispanica L.) seed exudate, a commonly used root exudate analogue. Sandy loam soil was passed through a 500-μm mesh and treated with each exudate at a concentration of 4.6 mg exudate g⁻¹ dry soil. Two sets of soil samples were prepared. One set of treated soil samples was maintained at 4°C to suppress microbial processes. To characterize the effect of decomposition, the second set of samples was incubated at 16°C for 2 weeks at −30 kPa matric potential. Gas chromatography–mass spectrometry (GC–MS) analysis of the exudates showed that barley had the largest organic acid content and chia the largest content of sugars (polysaccharide-derived or free), and maize was in between barley and chia. Yield stress of amended soil samples was measured by an oscillatory strain sweep test with a cone plate rheometer. When microbial decomposition was suppressed at 4°C, yield stress increased 20-fold for chia seed exudate and twofold for maize root exudate compared with the control, whereas for barley root exudate decreased to half. The yield stress after 2 weeks of incubation compared with soil with suppressed microbial decomposition increased by 85% for barley root exudate, but for chia and maize it decreased by 87 and 54%, respectively. Barley root exudation might therefore disperse soil and this could facilitate nutrient release. The maize root and chia seed exudates gelled soil, which could create a more stable soil structure around roots or seeds.
Original languageEnglish
Pages (from-to)806-816
Number of pages11
JournalEuropean Journal of Soil Science
Volume68
Issue number6
Early online date27 Oct 2017
DOIs
Publication statusPublished - 1 Nov 2017
Externally publishedYes

Fingerprint

plant exudates
root exudates
rhizosphere
barley
corn
maize
soil
soil sampling
seeds
seed
degradation
Salvia hispanica
decomposition
seed cones
exudation
sandy loam soils
optics
soil structure
hydroponics
sugar content

Cite this

Naveed, M. ; Brown, L.K. ; Raffan, A.C. ; George, T.S. ; Bengough, A.G. ; Roose, T. ; Sinclair, I. ; Koebernick, N. ; Cooper, L. ; Hackett, C.A. . / Plant exudates may stabilize or weaken soil depending on species, origin and time : Effect of plant exudates on rhizosphere formation. In: European Journal of Soil Science. 2017 ; Vol. 68, No. 6. pp. 806-816.
@article{cc8ce15da95c4ba9a38df3bfb424e78d,
title = "Plant exudates may stabilize or weaken soil depending on species, origin and time: Effect of plant exudates on rhizosphere formation",
abstract = "We hypothesized that plant exudates could either gel or disperse soil depending on their chemical characteristics. Barley (Hordeum vulgare L. cv. Optic) and maize (Zea mays L. cv. Freya) root exudates were collected using an aerated hydroponic method and compared with chia (Salvia hispanica L.) seed exudate, a commonly used root exudate analogue. Sandy loam soil was passed through a 500-μm mesh and treated with each exudate at a concentration of 4.6 mg exudate g⁻¹ dry soil. Two sets of soil samples were prepared. One set of treated soil samples was maintained at 4°C to suppress microbial processes. To characterize the effect of decomposition, the second set of samples was incubated at 16°C for 2 weeks at −30 kPa matric potential. Gas chromatography–mass spectrometry (GC–MS) analysis of the exudates showed that barley had the largest organic acid content and chia the largest content of sugars (polysaccharide-derived or free), and maize was in between barley and chia. Yield stress of amended soil samples was measured by an oscillatory strain sweep test with a cone plate rheometer. When microbial decomposition was suppressed at 4°C, yield stress increased 20-fold for chia seed exudate and twofold for maize root exudate compared with the control, whereas for barley root exudate decreased to half. The yield stress after 2 weeks of incubation compared with soil with suppressed microbial decomposition increased by 85{\%} for barley root exudate, but for chia and maize it decreased by 87 and 54{\%}, respectively. Barley root exudation might therefore disperse soil and this could facilitate nutrient release. The maize root and chia seed exudates gelled soil, which could create a more stable soil structure around roots or seeds.",
author = "M. Naveed and L.K. Brown and A.C. Raffan and T.S. George and A.G. Bengough and T. Roose and I. Sinclair and N. Koebernick and L. Cooper and C.A. Hackett",
year = "2017",
month = "11",
day = "1",
doi = "10.1111/ejss.12487",
language = "English",
volume = "68",
pages = "806--816",
journal = "European Journal of Soil Science",
issn = "1365-2389",
publisher = "John Wiley & Sons, Inc.",
number = "6",

}

Naveed, M, Brown, LK, Raffan, AC, George, TS, Bengough, AG, Roose, T, Sinclair, I, Koebernick, N, Cooper, L & Hackett, CA 2017, 'Plant exudates may stabilize or weaken soil depending on species, origin and time: Effect of plant exudates on rhizosphere formation', European Journal of Soil Science, vol. 68, no. 6, pp. 806-816. https://doi.org/10.1111/ejss.12487

Plant exudates may stabilize or weaken soil depending on species, origin and time : Effect of plant exudates on rhizosphere formation. / Naveed, M.; Brown, L.K.; Raffan, A.C. ; George, T.S. ; Bengough, A.G. ; Roose, T.; Sinclair, I.; Koebernick, N. ; Cooper, L.; Hackett, C.A. .

In: European Journal of Soil Science, Vol. 68, No. 6, 01.11.2017, p. 806-816.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Plant exudates may stabilize or weaken soil depending on species, origin and time

T2 - Effect of plant exudates on rhizosphere formation

AU - Naveed, M.

AU - Brown, L.K.

AU - Raffan, A.C.

AU - George, T.S.

AU - Bengough, A.G.

AU - Roose, T.

AU - Sinclair, I.

AU - Koebernick, N.

AU - Cooper, L.

AU - Hackett, C.A.

PY - 2017/11/1

Y1 - 2017/11/1

N2 - We hypothesized that plant exudates could either gel or disperse soil depending on their chemical characteristics. Barley (Hordeum vulgare L. cv. Optic) and maize (Zea mays L. cv. Freya) root exudates were collected using an aerated hydroponic method and compared with chia (Salvia hispanica L.) seed exudate, a commonly used root exudate analogue. Sandy loam soil was passed through a 500-μm mesh and treated with each exudate at a concentration of 4.6 mg exudate g⁻¹ dry soil. Two sets of soil samples were prepared. One set of treated soil samples was maintained at 4°C to suppress microbial processes. To characterize the effect of decomposition, the second set of samples was incubated at 16°C for 2 weeks at −30 kPa matric potential. Gas chromatography–mass spectrometry (GC–MS) analysis of the exudates showed that barley had the largest organic acid content and chia the largest content of sugars (polysaccharide-derived or free), and maize was in between barley and chia. Yield stress of amended soil samples was measured by an oscillatory strain sweep test with a cone plate rheometer. When microbial decomposition was suppressed at 4°C, yield stress increased 20-fold for chia seed exudate and twofold for maize root exudate compared with the control, whereas for barley root exudate decreased to half. The yield stress after 2 weeks of incubation compared with soil with suppressed microbial decomposition increased by 85% for barley root exudate, but for chia and maize it decreased by 87 and 54%, respectively. Barley root exudation might therefore disperse soil and this could facilitate nutrient release. The maize root and chia seed exudates gelled soil, which could create a more stable soil structure around roots or seeds.

AB - We hypothesized that plant exudates could either gel or disperse soil depending on their chemical characteristics. Barley (Hordeum vulgare L. cv. Optic) and maize (Zea mays L. cv. Freya) root exudates were collected using an aerated hydroponic method and compared with chia (Salvia hispanica L.) seed exudate, a commonly used root exudate analogue. Sandy loam soil was passed through a 500-μm mesh and treated with each exudate at a concentration of 4.6 mg exudate g⁻¹ dry soil. Two sets of soil samples were prepared. One set of treated soil samples was maintained at 4°C to suppress microbial processes. To characterize the effect of decomposition, the second set of samples was incubated at 16°C for 2 weeks at −30 kPa matric potential. Gas chromatography–mass spectrometry (GC–MS) analysis of the exudates showed that barley had the largest organic acid content and chia the largest content of sugars (polysaccharide-derived or free), and maize was in between barley and chia. Yield stress of amended soil samples was measured by an oscillatory strain sweep test with a cone plate rheometer. When microbial decomposition was suppressed at 4°C, yield stress increased 20-fold for chia seed exudate and twofold for maize root exudate compared with the control, whereas for barley root exudate decreased to half. The yield stress after 2 weeks of incubation compared with soil with suppressed microbial decomposition increased by 85% for barley root exudate, but for chia and maize it decreased by 87 and 54%, respectively. Barley root exudation might therefore disperse soil and this could facilitate nutrient release. The maize root and chia seed exudates gelled soil, which could create a more stable soil structure around roots or seeds.

U2 - 10.1111/ejss.12487

DO - 10.1111/ejss.12487

M3 - Article

VL - 68

SP - 806

EP - 816

JO - European Journal of Soil Science

JF - European Journal of Soil Science

SN - 1365-2389

IS - 6

ER -