info:eu-repo/semantics/article
Functional relationships between hydraulic traits and the timing of diurnal depression of photosynthesis
Fecha
2019-01-04Registro en:
Bucci, Sandra Janet; Carbonell Silletta, Luisina Marta; Garré, Analía; Cavallaro, Agustin; Efron, Samanta Thais; et al.; Functional relationships between hydraulic traits and the timing of diurnal depression of photosynthesis; Wiley Blackwell Publishing, Inc; Plant, Cell and Environment; 42; 5; 4-1-2019; 1603-1614
0140-7791
1365-3040
CONICET Digital
CONICET
Autor
Bucci, Sandra Janet
Carbonell Silletta, Luisina Marta
Garré, Analía
Cavallaro, Agustin
Efron, Samanta Thais
Arias, Nadia Soledad
Goldstein, Guillermo Hernan
Scholz, Fabian Gustavo
Resumen
The hydraulic coordination along the water transport pathway helps trees provide adequate water supply to the canopy, ensuring that water deficits are minimized and that stomata remain open for CO2 uptake. We evaluated the stem and leaf hydraulic coordination and the linkages between hydraulic traits and the timing of diurnal depression of photosynthesis across seven evergreen tree species in the southern Andes. There was a positive correlation between stem hydraulic conductivity (ks) and leaf hydraulic conductance (KLeaf) across species. All species had similar maximum photosynthetic rates (Amax). The species with higher ks and KLeaf attained Amax in the morning, whereas the species with lower ks and KLeaf exhibited their Amax in the early afternoon concurrently with turgor loss. These latter species had very negative leaf water potentials, but far from the pressure at which the 88% of leaf hydraulic conductance is lost. Our results suggest that diurnal gas exchange dynamics may be determined by leaf hydraulic vulnerability such that a species more vulnerable to drought restrict water loss and carbon assimilation earlier than species less vulnerable. However, under stronger drought, species with earlier CO2 uptake depression may increase the risk of hydraulic failure, as their safety margins are relatively narrow.