Accounting for sap flow from different parts of the root system improves the prediction of xylem ABA concentration in plants grown with heterogeneous soil moisture.

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ABA, deficit irrigation, grafting, irrigation scheduling, modelling, partial rootzone drying, sap flow, soil moisture heterogeneity

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Accounting for sap flow from different parts of the root system improves the prediction of xylem ABA concentration in plants grown with heterogeneous soil moisture. / Dodd, Ian C.; Egea, Gregorio; Davies, William J.
In: Journal of Experimental Botany, Vol. 59, No. 15, 11.2008, p. 4083-4093.

Research output: Contribution to Journal/Magazine › Journal article › peer-review

Bibtex

@article{2ab00416123f4362b030e725da80591f,

title = "Accounting for sap flow from different parts of the root system improves the prediction of xylem ABA concentration in plants grown with heterogeneous soil moisture.",

abstract = "When soil moisture is heterogeneous, sap flow from, and ABA status of, different parts of the root system impact on leaf xylem ABA concentration ([X-ABA]leaf). The robustness of a model for predicting [X-ABA]leaf was assessed. {\textquoteleft}Two root-one shoot{\textquoteright} grafted sunflower (Helianthus annuus L.) plants received either deficit irrigation (DI, each root system received the same irrigation volumes) or partial rootzone drying (PRD, only one root system was watered and the other dried the soil). Irrespective of whether relative sap flow was assessed using sap flow sensors in vivo or by pressurization of de-topped roots, each root system contributed similarly to total sap flow during DI, while sap flow from roots in drying soil declined linearly with soil water potential (soil) during PRD. Although soil of the irrigated pot determined the threshold soil at which sap flow from roots in drying soil decreased, the slope of this decrease was independent of the wet pot soil. Irrespective of whether sap was collected from the wet or dry root system of PRD plants, or a DI plant, root xylem ABA concentration increased as soil declined. The model, which weighted ABA contributions of each root system according to the sap flow from each, almost perfectly explained [X-ABA] immediately above the graft union. That the model overestimated measured [X-ABA]leaf may result from changes in [X-ABA] along the transport pathway or an artefact of collecting xylem sap from detached leaves. The implications of declining sap flow through partially dry roots during PRD for the control of stomatal behaviour and irrigation scheduling are discussed.",

keywords = "ABA, deficit irrigation, grafting, irrigation scheduling, modelling, partial rootzone drying, sap flow, soil moisture heterogeneity",

author = "Dodd, {Ian C.} and Gregorio Egea and Davies, {William J.}",

note = "This is an electronic version of an article published in Journal of Experimental Botany, 59 (15), 2008, p. 4083-4093.",

year = "2008",

month = nov,

doi = "10.1093/jxb/ern246",

language = "English",

volume = "59",

pages = "4083--4093",

journal = "Journal of Experimental Botany",

issn = "1460-2431",

publisher = "OXFORD UNIV PRESS",

number = "15",

}

RIS

TY - JOUR

T1 - Accounting for sap flow from different parts of the root system improves the prediction of xylem ABA concentration in plants grown with heterogeneous soil moisture.

AU - Dodd, Ian C.

AU - Egea, Gregorio

AU - Davies, William J.

N1 - This is an electronic version of an article published in Journal of Experimental Botany, 59 (15), 2008, p. 4083-4093.

PY - 2008/11

Y1 - 2008/11

N2 - When soil moisture is heterogeneous, sap flow from, and ABA status of, different parts of the root system impact on leaf xylem ABA concentration ([X-ABA]leaf). The robustness of a model for predicting [X-ABA]leaf was assessed. ‘Two root-one shoot’ grafted sunflower (Helianthus annuus L.) plants received either deficit irrigation (DI, each root system received the same irrigation volumes) or partial rootzone drying (PRD, only one root system was watered and the other dried the soil). Irrespective of whether relative sap flow was assessed using sap flow sensors in vivo or by pressurization of de-topped roots, each root system contributed similarly to total sap flow during DI, while sap flow from roots in drying soil declined linearly with soil water potential (soil) during PRD. Although soil of the irrigated pot determined the threshold soil at which sap flow from roots in drying soil decreased, the slope of this decrease was independent of the wet pot soil. Irrespective of whether sap was collected from the wet or dry root system of PRD plants, or a DI plant, root xylem ABA concentration increased as soil declined. The model, which weighted ABA contributions of each root system according to the sap flow from each, almost perfectly explained [X-ABA] immediately above the graft union. That the model overestimated measured [X-ABA]leaf may result from changes in [X-ABA] along the transport pathway or an artefact of collecting xylem sap from detached leaves. The implications of declining sap flow through partially dry roots during PRD for the control of stomatal behaviour and irrigation scheduling are discussed.

AB - When soil moisture is heterogeneous, sap flow from, and ABA status of, different parts of the root system impact on leaf xylem ABA concentration ([X-ABA]leaf). The robustness of a model for predicting [X-ABA]leaf was assessed. ‘Two root-one shoot’ grafted sunflower (Helianthus annuus L.) plants received either deficit irrigation (DI, each root system received the same irrigation volumes) or partial rootzone drying (PRD, only one root system was watered and the other dried the soil). Irrespective of whether relative sap flow was assessed using sap flow sensors in vivo or by pressurization of de-topped roots, each root system contributed similarly to total sap flow during DI, while sap flow from roots in drying soil declined linearly with soil water potential (soil) during PRD. Although soil of the irrigated pot determined the threshold soil at which sap flow from roots in drying soil decreased, the slope of this decrease was independent of the wet pot soil. Irrespective of whether sap was collected from the wet or dry root system of PRD plants, or a DI plant, root xylem ABA concentration increased as soil declined. The model, which weighted ABA contributions of each root system according to the sap flow from each, almost perfectly explained [X-ABA] immediately above the graft union. That the model overestimated measured [X-ABA]leaf may result from changes in [X-ABA] along the transport pathway or an artefact of collecting xylem sap from detached leaves. The implications of declining sap flow through partially dry roots during PRD for the control of stomatal behaviour and irrigation scheduling are discussed.

KW - ABA

KW - deficit irrigation

KW - grafting

KW - irrigation scheduling

KW - modelling

KW - partial rootzone drying

KW - sap flow

KW - soil moisture heterogeneity

UR - http://www.scopus.com/inward/record.url?scp=57149086648&partnerID=8YFLogxK

U2 - 10.1093/jxb/ern246

DO - 10.1093/jxb/ern246

M3 - Journal article

VL - 59

SP - 4083

EP - 4093

JO - Journal of Experimental Botany

JF - Journal of Experimental Botany

SN - 1460-2431

IS - 15

ER -

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