Phenotypic plasticity and genetic adaptation of functional traits influences intra-specific variation in hydraulic efficiency and safety
Understanding which hydraulic traits are under genetic control and/or are phenotypically plastic is essential in understanding how tree species will respond to rapid shifts in climate. We quantified hydraulic traits in Eucalyptus obliqua across a precipitation gradient in the field to describe: 1) trait variation in relation to long-term climate and 2) the short-term (seasonal) ability of traits to adjust (i.e., phenotypic plasticity). Seedlings from each field population were raised under controlled conditions to assess: 3) which traits are under strong genetic control. In the field, drier populations had smaller leaves with anatomically thicker xylem vessel walls, a lower leaf hydraulic vulnerability and a lower water potential at turgor loss point, which likely confers higher hydraulic safety. Traits such as the water potential at turgor loss point and ratio of sapwood to leaf area (Huber Value) showed significant adjustment from wet to dry conditions in the field, indicating phenotypic plasticity and importantly, the ability to increase hydraulic safety in the short-term. In the nursery, seedlings from drier populations had smaller leaves and a lower leaf hydraulic vulnerability, suggesting key traits associated with hydraulic safety are under strong genetic control. Overall, our study suggests that strong genetic control over traits associated with hydraulic safety, which may compromise the survival of wet-origin populations in drier future climates. However, phenotypic plasticity in physiological and morphological traits may confer sufficient hydraulic safety to facilitate genetic adaptation.
History
Publication title
Tree PhysiologyArticle number
tpz121Number
tpz121ISSN
0829-318XDepartment/School
School of Natural SciencesPublisher
Heron PublishingPlace of publication
202, 3994 Shelbourne St, Victoria, Canada, Bc, V8N 3E2Rights statement
Copyright 2019 The Authors. This is a pre-copyedited, author-produced version of an article accepted for publication in Tree Physiology following peer review. The version of record is available online at: http://dx.doi.org/10.1093/treephys/tpz121Repository Status
- Restricted