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Night‐time transpiration can decrease hydraulic redistribution
Author(s) -
HOWARD AVA R.,
VAN IERSEL MARC W.,
RICHARDS JAMES H.,
DONOVAN LISA A.
Publication year - 2009
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.1365-3040.2009.01988.x
Subject(s) - transpiration , vapour pressure deficit , canopy , cycling , environmental science , soil water , nutrient , horticulture , nutrient cycle , agronomy , zoology , botany , biology , ecology , photosynthesis , forestry , soil science , geography
C 3 plants dominate many landscapes and are critically important for ecosystem water cycling. At night, plant water losses can include transpiration (E night ) from the canopy and hydraulic redistribution (HR) from roots. We tested whether E night limits the magnitude of HR in a greenhouse study using Artemisia tridentata , Helianthus anomalus and Quercus laevis . Plants were grown with their roots split between two compartments. HR was initiated by briefly withholding all water, followed by watering only one rooting compartment. Under study conditions, all species showed substantial E night and HR (highest minus lowest soil water potential [ Ψ s ] during a specified diel period). Suppressing E night by canopy bagging increased HR during the nightly bagging period (HR N ) for A. tridentata and H. anomalus by 73 and 33% respectively, but did not affect HR N by Q. laevis . Total daily HR (HR T ) was positively correlated with the Ψ s gradient between the rooting compartments, which was correlated with light and/or atmospheric vapour pressure deficit (VPDa) the prior day. For A. tridentata , HR T was negatively correlated with night‐time VPDa. Ecological implications of the impact of E night on HR may include decreased plant productivity during dry seasons, altered ecosystem water flux patterns and reduced nutrient cycling in drying soils.