Limited Phenotypic Variation in Vulnerability to Cavitation and Stomatal Sensitivity to Vapor Pressure Deficit among Clones of Aristotelia chilensis from Different Climatic Origins.

ABSTRACT

Aristotelia chilensis (Molina) Stuntz is a promising species in the food industry as it provides 'super fruits' with remarkable antioxidant activity. However, under the predicted climate change scenario, the ongoing domestication of the species must consider selecting the most productive genotypes and be based on traits conferring drought tolerance. We assessed the vulnerability to cavitation and stomatal sensitivity to vapor pressure deficit (VPD) in A. chilensis clones originated from provenances with contrasting climates. A nursery experiment was carried out for one growing season on 2-year-old potted plants. Measurements of stomatal conductance (gs) responses to VPD were taken in spring, summer, and autumn, whereas vulnerability to cavitation was evaluated at the end of spring. Overall, the vulnerability to cavitation of the species was moderate (mean P50 of -2.2 MPa). Parameters of the vulnerability curves (Kmax, P50, P88, and S50) showed no differences among clones or when northern and southern clones were compared. Moreover, there were no differences in stomatal sensitivity to VPD at the provenance or the clonal level. However, compared with other studies, the stomatal sensitivity was considered moderately low, especially in the range of 1 to 3 kPa of VPD. The comparable performance of genotypes from contrasting provenance origins suggests low genetic variation for these traits. Further research must consider testing on diverse environmental conditions to assess the phenotypic plasticity of these types of traits.