Sequential defoliation impacts on colonisation of roots of Lolium rigidum by arbuscular mycorrhizal fungi were primarily determined by root responses

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Abstract

Defoliation often has little effect on the percent plant root length colonised by arbuscular mycorrhizal (AM) fungi, and this has been interpreted as a lack of support for the carbon limitation hypothesis. We performed an experiment with three levels of repeated defoliation (none, every 3 weeks and weekly) of Lolium rigidum growing in pasture soil, and assessed colonisation of roots by naturally occurring AM fungi over 4 months in the glasshouse. Surprisingly, the percent root length colonised by AM fungi increased with defoliation. We also assessed root mass and the length of colonised root to obtain an estimate of the quantity of mycorrhizal root. As expected, both root mass and length of mycorrhizal root decreased with defoliation, as did soluble sugars in the roots. Thus, increasing the frequency of defoliation reduced mycorrhizas consistent with the carbon-limitation hypothesis. Such a decline in mass of mycorrhizal root could contribute to reducing soil biological fertility in pastures over time.

Original languageEnglish
JournalBiology and Fertility of Soils
DOIs
Publication statusE-pub ahead of print - 5 Aug 2019

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Lolium rigidum
Lolium
defoliation
mycorrhizal fungi
Fungi
colonization
fungus
Soil
Carbon
Plant Roots
Fertility
pastures
carbon
mycorrhizae
soil fertility
soil
pasture
sugars
greenhouses
fertility

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@article{a55384a2626448c9924bb5288a7c4b65,
title = "Sequential defoliation impacts on colonisation of roots of Lolium rigidum by arbuscular mycorrhizal fungi were primarily determined by root responses",
abstract = "Defoliation often has little effect on the percent plant root length colonised by arbuscular mycorrhizal (AM) fungi, and this has been interpreted as a lack of support for the carbon limitation hypothesis. We performed an experiment with three levels of repeated defoliation (none, every 3 weeks and weekly) of Lolium rigidum growing in pasture soil, and assessed colonisation of roots by naturally occurring AM fungi over 4 months in the glasshouse. Surprisingly, the percent root length colonised by AM fungi increased with defoliation. We also assessed root mass and the length of colonised root to obtain an estimate of the quantity of mycorrhizal root. As expected, both root mass and length of mycorrhizal root decreased with defoliation, as did soluble sugars in the roots. Thus, increasing the frequency of defoliation reduced mycorrhizas consistent with the carbon-limitation hypothesis. Such a decline in mass of mycorrhizal root could contribute to reducing soil biological fertility in pastures over time.",
keywords = "Arbuscular mycorrhiza, Carbon limitation hypothesis, Grazing, Pasture, Rhizosphere, Soluble carbon",
author = "Fan, {Jing Wei} and Solaiman, {Zakaria M.} and Mickan, {Bede S.} and Du, {Yan Lei} and Li, {Feng Min} and Abbott, {Lynette K.}",
year = "2019",
month = "8",
day = "5",
doi = "10.1007/s00374-019-01394-3",
language = "English",
journal = "Biology and Fertility of Soils",
issn = "0178-2762",
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T1 - Sequential defoliation impacts on colonisation of roots of Lolium rigidum by arbuscular mycorrhizal fungi were primarily determined by root responses

AU - Fan, Jing Wei

AU - Solaiman, Zakaria M.

AU - Mickan, Bede S.

AU - Du, Yan Lei

AU - Li, Feng Min

AU - Abbott, Lynette K.

PY - 2019/8/5

Y1 - 2019/8/5

N2 - Defoliation often has little effect on the percent plant root length colonised by arbuscular mycorrhizal (AM) fungi, and this has been interpreted as a lack of support for the carbon limitation hypothesis. We performed an experiment with three levels of repeated defoliation (none, every 3 weeks and weekly) of Lolium rigidum growing in pasture soil, and assessed colonisation of roots by naturally occurring AM fungi over 4 months in the glasshouse. Surprisingly, the percent root length colonised by AM fungi increased with defoliation. We also assessed root mass and the length of colonised root to obtain an estimate of the quantity of mycorrhizal root. As expected, both root mass and length of mycorrhizal root decreased with defoliation, as did soluble sugars in the roots. Thus, increasing the frequency of defoliation reduced mycorrhizas consistent with the carbon-limitation hypothesis. Such a decline in mass of mycorrhizal root could contribute to reducing soil biological fertility in pastures over time.

AB - Defoliation often has little effect on the percent plant root length colonised by arbuscular mycorrhizal (AM) fungi, and this has been interpreted as a lack of support for the carbon limitation hypothesis. We performed an experiment with three levels of repeated defoliation (none, every 3 weeks and weekly) of Lolium rigidum growing in pasture soil, and assessed colonisation of roots by naturally occurring AM fungi over 4 months in the glasshouse. Surprisingly, the percent root length colonised by AM fungi increased with defoliation. We also assessed root mass and the length of colonised root to obtain an estimate of the quantity of mycorrhizal root. As expected, both root mass and length of mycorrhizal root decreased with defoliation, as did soluble sugars in the roots. Thus, increasing the frequency of defoliation reduced mycorrhizas consistent with the carbon-limitation hypothesis. Such a decline in mass of mycorrhizal root could contribute to reducing soil biological fertility in pastures over time.

KW - Arbuscular mycorrhiza

KW - Carbon limitation hypothesis

KW - Grazing

KW - Pasture

KW - Rhizosphere

KW - Soluble carbon

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U2 - 10.1007/s00374-019-01394-3

DO - 10.1007/s00374-019-01394-3

M3 - Article

JO - Biology and Fertility of Soils

JF - Biology and Fertility of Soils

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