Interactive effects of elevated CO 2 and drought on nocturnal water fluxes in Eucalyptus saligna

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dc.contributor.author Zeppel, MJB
dc.contributor.author Lewis, JD
dc.contributor.author Medlyn, B
dc.contributor.author Barton, CVM
dc.contributor.author Duursma, RA
dc.contributor.author Eamus, D
dc.contributor.author Adams, MA
dc.contributor.author Phillips, N
dc.contributor.author Ellsworth, DS
dc.contributor.author Forster, MA
dc.contributor.author Tissue, DT
dc.date.accessioned 2012-10-12T03:33:26Z
dc.date.issued 2011-09
dc.identifier.citation Tree Physiology, 2011, 31 (9), pp. 932 - 944
dc.identifier.issn 0829-318X
dc.identifier.other C1 en_US
dc.identifier.uri http://hdl.handle.net/10453/18144
dc.description.abstract Nocturnal water flux has been observed in trees under a variety of environmental conditions and can be a significant contributor to diel canopy water flux. Elevated atmospheric CO 2 (elevated [CO 2]) can have an important effect on day-time plant water fluxes, but it is not known whether it also affects nocturnal water fluxes. We examined the effects of elevated [CO 2] on nocturnal water flux of field-grown Eucalyptus saligna trees using sap flux through the tree stem expressed on a sapwood area (J s) and leaf area (E t) basis. After 19 months growth under well-watered conditions, drought was imposed by withholding water for 5 months in the summer, ending with a rain event that restored soil moisture. Reductions in J s and E t were observed during the severe drought period in the dry treatment under elevated [CO 2], but not during moderate- and post-drought periods. Elevated [CO 2] affected night-time sap flux density which included the stem recharge period, called 'total night flux' (19:00 to 05:00, J s,r), but not during the post-recharge period, which primarily consisted of canopy transpiration (23:00 to 05:00, J s,c). Elevated [CO 2] wet (EW) trees exhibited higher J s,r than ambient [CO 2] wet trees (AW) indicating greater water flux in elevated [CO 2] under well-watered conditions. However, under drought conditions, elevated [CO 2] dry (ED) trees exhibited significantly lower J s,r than ambient [CO 2] dry trees (AD), indicating less water flux during stem recharge under elevated [CO 2]. J s,c did not differ between ambient and elevated [CO 2]. Vapour pressure deficit (D) was clearly the major influence on night-time sap flux. D was positively correlated with J s,r and had its greatest impact on J s,r at high D in ambient [CO 2]. Our results suggest that elevated [CO 2] may reduce night-time water flux in E. saligna when soil water content is low and D is high. While elevated [CO 2] affected J s,r, it did not affect day-time water flux in wet soil, suggesting that the responses of J s,r to environmental factors cannot be directly inferred from day-time patterns. Changes in J s,r are likely to influence pre-dawn leaf water potential, and plant responses to water stress. Nocturnal fluxes are clearly important for predicting effects of climate change on forest physiology and hydrology. © 2011 The Author. Published by Oxford University Press. A ll rights reserved.
dc.language eng
dc.relation.hasversion Accepted manuscript version
dc.relation.isbasedon 10.1093/treephys/tpr024
dc.title Interactive effects of elevated CO 2 and drought on nocturnal water fluxes in Eucalyptus saligna
dc.type Journal Article
dc.parent Tree Physiology
dc.journal.volume 9
dc.journal.volume 31
dc.journal.number 9 en_US
dc.publocation UK en_US
dc.identifier.startpage 932 en_US
dc.identifier.endpage 944 en_US
dc.cauo.name SCI.Faculty of Science en_US
dc.conference Verified OK en_US
dc.for 060705 Plant Physiology
dc.personcode 000006
dc.personcode 034078
dc.percentage 100 en_US
dc.classification.name Plant Physiology en_US
dc.classification.type FOR-08 en_US
dc.edition en_US
dc.custom en_US
dc.date.activity en_US
dc.location.activity en_US
dc.description.keywords drought
dc.description.keywords elevated CO 2
dc.description.keywords nocturnal
dc.description.keywords sap flow
dc.description.keywords sap flux
dc.description.keywords transpiration
pubs.embargo.period Not known
pubs.organisational-group /University of Technology Sydney
pubs.organisational-group /University of Technology Sydney/Faculty of Science
utslib.copyright.status Open Access
utslib.copyright.date 2015-04-15 12:23:47.074767+10
pubs.consider-herdc true
utslib.collection.history General (ID: 2)
utslib.collection.history School of the Environment (ID: 344)


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