High safety margins to drought-induced hydraulic failure found in five pasture grasses.
Plant Cell Environ
; 45(6): 1631-1646, 2022 06.
Article
em En
| MEDLINE
| ID: mdl-35319101
ABSTRACT
Determining the relationship between reductions in stomatal conductance (gs ) and leaf water transport during dehydration is key to understanding plant drought responses. While numerous studies have analysed the hydraulic function of woody species, minimal research has been conducted on grasses. Here, we sought to characterize hydraulic vulnerability in five widely-occurring pasture grasses (including both C3 and C4 grasses) and determine whether reductions in gs and leaf hydraulic conductance (Kleaf ) during dehydration could be attributed to xylem embolism. Using the optical vulnerability (OV) technique, we found that all species were highly resistant to xylem embolism when compared to other herbaceous angiosperms, with 50% xylem embolism (PX50 ) occurring at xylem pressures ranging from -4.4 to -6.1 MPa. We observed similar reductions in gs and Kleaf under mild water stress for all species, occurring well before PX50 . The onset of xylem embolism (PX12 ) occurred consistently after stomatal closure and 90% reduction of Kleaf . Our results suggest that factors other than xylem embolism are responsible for the majority of reductions in gs and Kleaf during drought and reductions in the productivity of pasture species under moderate drought may not be driven by embolism.
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01-internacional
Base de dados:
MEDLINE
Assunto principal:
Embolia
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Secas
Idioma:
En
Revista:
Plant Cell Environ
Assunto da revista:
BOTANICA
Ano de publicação:
2022
Tipo de documento:
Article
País de afiliação:
Austrália