Intraspecific variability in vulnerability to xylem cavitation as the basis for drought resistance selection

DALLA SALDA G; SERGENT AS; FERNÁNDEZ M.E.; ROZENBERG P; MARTÍNEZ MEIER A

Corrientes

Congreso; XXXI Reunión Argentina de Fisiología Vegetal; 2016

Soc. Arg. de Fisiología Vegetal

Vulnerabilityto cavitation curves describe how much the hydraulic conductivity of a givenstem segment decreases when exposed to a gradual increase in xylem tension.Vulnerability to cavitation therefore offers a quantitative assessment of theability of the conduits of a given plant to sustain the tensions experienced inthe face of water deficit. The xylem pressure causing 50% loss of conductivity(P50) is of ecological significance and is widely used to characterize thedrought tolerance of plant species. It varies widely among species (from −1.5to −14 MPa) and has been shown to correlate with the drought-responsestrategies of plants and with the water potential thresholds at which plantsfail to recover from drought. However, intraspecific studies are much lessnumerous probably because of practical issues. In some species likeDouglas-Fir, Norway spruce or Cordilleran cypress, show that genetic variationwas found for the parameters of the vulnerability to cavitation curve. Theseresults are important and can be considered the basis for natural selection incases of response to climate change in natural forests, or artificial selectionin a breeding program.