Rights statement: This is the peer reviewed version of the following article:Brunn, M., Hafner, B.D., Zwetsloot, M.J., Weikl, F., Pritsch, K., Hikino, K., Ruehr, N.K., Sayer, E.J. and Bauerle, T.L. (2022), Carbon allocation to root exudates is maintained in mature temperate tree species under drought. New Phytol, 235: 965-977. doi: 10.1111/nph.18157 which has been published in final form at https://nph.onlinelibrary.wiley.com/doi/10.1111/nph.18157 This article may be used for non-commercial purposes in accordance With Wiley Terms and Conditions for self-archiving.
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Final published version
Licence: CC BY: Creative Commons Attribution 4.0 International License
Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
}
TY - JOUR
T1 - Carbon allocation to root exudates is maintained in mature temperate tree species under drought
AU - Brunn, Melanie
AU - Hafner, Benjamin D.
AU - Zwetsloot, Marie J.
AU - Weikl, Fabian
AU - Pritsch, Karin
AU - Hikino, Kyohsuke
AU - Ruehr, Nadine K.
AU - Sayer, Emma
AU - Bauerle, Taryn L.
N1 - This is the peer reviewed version of the following article:Brunn, M., Hafner, B.D., Zwetsloot, M.J., Weikl, F., Pritsch, K., Hikino, K., Ruehr, N.K., Sayer, E.J. and Bauerle, T.L. (2022), Carbon allocation to root exudates is maintained in mature temperate tree species under drought. New Phytol, 235: 965-977. doi: 10.1111/nph.18157 which has been published in final form at https://nph.onlinelibrary.wiley.com/doi/10.1111/nph.18157 This article may be used for non-commercial purposes in accordance With Wiley Terms and Conditions for self-archiving.
PY - 2022/8/31
Y1 - 2022/8/31
N2 - Carbon (C) exuded via roots is proposed to increase under drought and facilitate important ecosystem functions. However, it is unknown how exudate quantities relate to the total C budget of a drought-stressed tree, i.e. how much of net-C assimilation is allocated to exudation at the tree level.We calculated the proportion of daily C assimilation allocated to root exudation during early summer by collecting root exudates from mature Fagus sylvatica and Picea abies exposed to experimental drought, and combining above- and belowground C fluxes with leaf, stem, and fine-root surface area.Exudation from individual roots increased exponentially with decreasing soil moisture, with the highest increase at the wilting point. Despite ~50 % reduced C assimilation under drought, exudation from fine-root systems was maintained and trees exuded 1.0 % (F. sylvatica) to 2.5 % (P. abies) of net C into the rhizosphere, increasing the proportion of C allocation to exudates two- to threefold. Water-limited P. abies released two-thirds of its exudate-C into the surface soil, whereas it was only one-third in droughted F. sylvatica.Across the entire root system, droughted trees maintained exudation similar to controls, suggesting drought-imposed belowground C investment, which could be beneficial for ecosystem resilience.
AB - Carbon (C) exuded via roots is proposed to increase under drought and facilitate important ecosystem functions. However, it is unknown how exudate quantities relate to the total C budget of a drought-stressed tree, i.e. how much of net-C assimilation is allocated to exudation at the tree level.We calculated the proportion of daily C assimilation allocated to root exudation during early summer by collecting root exudates from mature Fagus sylvatica and Picea abies exposed to experimental drought, and combining above- and belowground C fluxes with leaf, stem, and fine-root surface area.Exudation from individual roots increased exponentially with decreasing soil moisture, with the highest increase at the wilting point. Despite ~50 % reduced C assimilation under drought, exudation from fine-root systems was maintained and trees exuded 1.0 % (F. sylvatica) to 2.5 % (P. abies) of net C into the rhizosphere, increasing the proportion of C allocation to exudates two- to threefold. Water-limited P. abies released two-thirds of its exudate-C into the surface soil, whereas it was only one-third in droughted F. sylvatica.Across the entire root system, droughted trees maintained exudation similar to controls, suggesting drought-imposed belowground C investment, which could be beneficial for ecosystem resilience.
KW - Belowground-carbon allocation
KW - carbon partitioning
KW - experimental drought
KW - Fagus sylvatica (European beech)
KW - fine-root exudation
KW - Picea abies (Norway spruce)
KW - rhizosphere
KW - temperate-forest C budget
U2 - 10.1111/nph.18157
DO - 10.1111/nph.18157
M3 - Journal article
VL - 235
SP - 965
EP - 977
JO - New Phytologist
JF - New Phytologist
SN - 0028-646X
IS - 3
ER -