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Nocturnal stomatal conductance responses to rising [CO 2 ], temperature and drought
Author(s) -
Zeppel Melanie J. B.,
Lewis James D.,
Chaszar Brian,
Smith Renee A.,
Medlyn Belinda E.,
Huxman Travis E.,
Tissue David T.
Publication year - 2012
Publication title -
new phytologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.742
H-Index - 244
eISSN - 1469-8137
pISSN - 0028-646X
DOI - 10.1111/j.1469-8137.2011.03993.x
Subject(s) - stomatal conductance , nocturnal , water use efficiency , transpiration , conductance , chemistry , environmental science , zoology , botany , photosynthesis , biology , ecology , mathematics , combinatorics
Summary• The response of nocturnal stomatal conductance ( g s,n ) to rising atmospheric CO 2 concentration ([CO 2 ]) is currently unknown, and may differ from responses of daytime stomatal conductance ( g s,d ). Because night‐time water fluxes can have a significant impact on landscape water budgets, an understanding of the effects of [CO 2 ] and temperature on g s,n is crucial for predicting water fluxes under future climates. • Here, we examined the effects of [CO 2 ] (280, 400 and 640 μmol mol −1 ), temperature (ambient and ambient + 4°C) and drought on g s,n, and g s,d in Eucalyptus sideroxylon saplings. • gs,n was substantially higher than zero, averaging 34% of g s,d . Before the onset of drought, g s,n increased by 85% when [CO 2 ] increased from 280 to 640 μmol mol −1 , averaged across both temperature treatments. g s,n declined with drought, but an increase in [CO 2 ] slowed this decline. Consequently, the soil water potential at which g s,n was zero (Ψ 0 ) was significantly more negative in elevated [CO 2 ] and temperature treatments. g s,d showed inconsistent responses to [CO 2 ] and temperature. • gs,n may be higher in future climates, potentially increasing nocturnal water loss and susceptibility to drought, but cannot be predicted easily from g s,d . Therefore, predictive models using stomatal conductance must account for both g s,n and g s,d when estimating ecosystem water fluxes.