Premium
The apparent feed‐forward response to vapour pressure deficit of stomata in droughted, field‐grown Eucalyptus globulus Labill
Author(s) -
MACFARLANE C.,
WHITE D. A.,
ADAMS M. A.
Publication year - 2004
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/j.1365-3040.2004.01234.x
Subject(s) - vapour pressure deficit , transpiration , stomatal conductance , photosynthesis , eucalyptus globulus , guard cell , abscisic acid , botany , chemistry , horticulture , biology , eucalyptus , biochemistry , gene
This study tested a multiplicative model of stomatal response to environment for drought‐affected trees of Eucalyptus globulus Labill. growing in southern Australia. The model incorporates a feed‐forward response to vapour pressure deficit of ambient air ( δe a ) and performed well if evaluated using reduced major axis regression and log‐transformed data. There was strong evidence from gas‐exchange data, leaf water potentials and sapflow measurements of the feed‐forward response by stomata to leaf‐to‐air vapour pressure deficit ( δe l ). The response of stomata to δe l was irreversible. Stomatal conductance and the rate of net photosynthesis were highly correlated and declined, together with the rate of transpiration, throughout the afternoon as δe a increased despite increasing leaf water potentials. The concentration of CO 2 inside leaves ( c i ) increased as stomatal conductance declined indicating increasing non‐stomatal limitations to photosynthesis. The stomatal response to δe l of E. globulus in the field is best described as an ‘apparent feed‐forward response’ that probably results from both slowly reversible depression of net photosynthesis and abscisic acid accumulation in guard cells. We suggest that the stomatal response to c i may strengthen the link between photosynthetic capacity and stomatal conductance during leaf drying as a result of either drought or large δ e l .