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Stomatal regulation in a changing climate: a field study using Free Air Temperature Increase (FATI) and Free Air CO 2 Enrichment (FACE)
Author(s) -
NIJS I.,
FERRIS R.,
BLUM H.,
HENDREY G.,
IMPENS I.
Publication year - 1997
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.1365-3040.1997.tb00680.x
Subject(s) - transpiration , stomatal conductance , microclimate , lolium perenne , canopy , atmospheric sciences , environmental science , vapour pressure of water , air temperature , chemistry , agronomy , water vapor , horticulture , botany , ecology , photosynthesis , perennial plant , biology , biochemistry , organic chemistry , geology
This study investigates effects of climate warming (+ 2.5°C ubove ambient) and elevated CO 2 concentration (600 μmol mol −1 ) on the stomatal functioning and the water relations of Lolium perenne , using Free Air Temperature Increase (FATI) and Free Air CO 2 Enrichment (FACE). Compared to growth at ambient temperature, whole‐season temperature increase reduced leaf stomatal conductance, but only at the top of the canopy (‐14.6 and ‐8.8% at ambient and elevated CO 2 , respectively). However, because higher canopy temperature raised the leaf‐to‐air vapour pressure difference, leaf transpiration rate increased (+28% at ambient and +48% at elevated CO 2 ) and instantaneous leaf water use efficiency, derived from short‐term measurements of assimilation and transpiration rate, declined (‐11% at ambient and ‐13% at elevated CO 2 ). Nevertheless, at the stand level, growth at + 2.5°C reduced transpiration due to fewer tillers per plant and a smaller leaf area per tiller. This sparser vegetation was also more closely coupled to the atmosphere and maintained a drier internal microclimate. To assess whether the stomatal behaviour observed in this experiment could be explained by prevailing concepts of stomatal functioning, three models were applied (Cowan 1977; Ball, Woodrow & Berry 1987; Leuning 1995). The latter model accounted for the highest proportion of variability in the data (58%) and was insensitive to CO 2 and temperature regime, which suggests that the principles of stomatal regulation are not affected by changes in CO 2 or climate.