Night-time transpiration can decrease hydraulic redistribution.
Plant Cell Environ
; 32(8): 1060-70, 2009 Aug.
Article
em En
| MEDLINE
| ID: mdl-19422615
ABSTRACT
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 [Psi(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 Psi(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.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Água
/
Fotoperíodo
/
Transpiração Vegetal
/
Raízes de Plantas
Idioma:
En
Revista:
Plant Cell Environ
Assunto da revista:
BOTANICA
Ano de publicação:
2009
Tipo de documento:
Article
País de afiliação:
Estados Unidos