title: Divergent climate response on hydraulic-related xylem anatomical traits of Picea abies along a 900-m altitudinal gradient.
abstract: Climate change can induce substantial modifications in xylem structure and water transport capacity of trees exposed to environmental constraints. To elucidate mechanisms of xylem plasticity in response to climate, we retrospectively analysed different cell anatomical parameters over tree-ring series in Norway spruce (Picea abies L. Karst.). We sampled 24 trees along an altitudinal gradient (1200, 1600 and 2100 m above sea level, a.s.l.) and processed 2335 ± 1809 cells per ring. Time series for median cell lumen area (MCA), cell number (CN), tree-ring width (RW) and tree-ring-specific hydraulic conductivity (Kr) were crossed with daily temperature and precipitation records (1926-2011) to identify climate influence on xylem anatomical traits. Higher Kr at the low elevation site was due to higher MCA and CN. These variables were related to different aspects of intra-seasonal climatic variability under different environmental conditions, with MCA being more sensitive to summer precipitation. Winter precipitation (snow) benefited most parameters in all the sites. Descending the gradient, sensitivity of xylem features to summer climate shifted mostly from temperature to precipitation. In the context of climate change, our results indicate that higher summer temperatures at high elevations will benefit cell production and xylem hydraulic efficiency, whereas reduced water availability at lower elevations could negatively affect tracheids enlargement and thus stem capacity to transport water.
authors.affiliation: Università degli Studi di Padova, Dept Territorio e Sistemi Agro-Forestali, Viale dell'Università 16, I-35020 Legnaro (PD), Italy daniele.castagneri@unipd.it.
authors.forename: Daniele
authors.initials: D
authors.lastname: Castagneri
authors.affiliation: Università degli Studi di Padova, Dept Territorio e Sistemi Agro-Forestali, Viale dell'Università 16, I-35020 Legnaro (PD), Italy.
authors.forename: Giai
authors.initials: G
authors.lastname: Petit
authors.affiliation: Università degli Studi di Padova, Dept Territorio e Sistemi Agro-Forestali, Viale dell'Università 16, I-35020 Legnaro (PD), Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Carrer
mesh_terms: D000531:Altitude; D002980:Climate; D057231:Climate Change; D007558:Italy; D028222:Picea / Q000033:anatomy & histology* / Q000502:physiology*; D052584:Xylem / Q000033:anatomy & histology / Q000502:physiology
keywords: Norway spruce; conductivity; lumen area; tracheid; tree ring