IFAB   27864
INSTITUTO DE INVESTIGACIONES FORESTALES Y AGROPECUARIAS BARILOCHE
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Differences among Nothofagus pumilio populations in tolerance to drought in a common garden experiment
Autor/es:
MATTERA MG; MARCHELLI P; AZPILICUETA, M. M.; DALLA SALDA, G.; SOLIANI C; ARANA ,MV
Lugar:
Bariloche
Reunión:
Conferencia; International Conference ?Adapting forests ecosystems and wood products to biotic and abiotic stress?; 2019
Institución organizadora:
INTA - INRA
Resumen:
Tolerance to stressing factors can be studied through the characterization of populations holding adapted genotypes, coming from different environmental origins. Accordingly, the ecophysiological response of Nothofagus pumilio to drought tolerance was evaluated on populations from a pluviometric gradient, in a common garden trial. We hypothesized that the population response has a genetic base determined by the selection pressure of its own native site. Therefore, we predict that the xeric populations will be less vulnerable to cavitation, i.e. the individuals from dryer origins will have minor loss of hydraulic conductivity under simulated conditions of water deficit. A split-plot experimental design with replicates (three blocks) was used, being the watering treatment the main factor (with two levels: regular irrigation, no irrigation) and the provenance of material the split factor (three contrasting origins: humid, intermediate and xeric). Individuals from each population were firstly characterized by measuring morphological (i.e. height, collar diameter) and anatomical (i.e. stomatal density and specific leaf area) traits and by performing curves of cavitation vulnerability. In addition, stomatal conductivity and volumetric water content of the pots were measured twice a week. At different moments along the experiment, pre-dawn and minimum water potential was measured and pressure-volume curves were performed. To evaluate signals of selection a comparison between PT obtained from neutral microsatellites (seven loci) and PST obtained from the measured phenotypical variables was done. Significant differences in pre-dawn water potential were found between irrigation treatments after 10 days of assay initiation and to its end, a point in which stomatal conductance significantly differed between treatments. Differences in physiological response were detected at population level. A significantly higher cavitation vulnerability (less negative P50) and narrower safety margin (lower water potential) were detected in the humid provenance. Within the stress plot, i.e. water deprivation, the xeric and the messic populations differed in the minimum water potential but not at it maximum. Signals of selection were detected for some of the traits (PST > PT). During early stages, the identification of differential adaptive capacity to water stress in native populations may be the key for successful domestication programs.