Limited plasticity of anatomical and hydraulic traits in aspen trees under elevated CO2 and seasonal drought

Abstract

The timing of abiotic stress elicitors on wood formation largely affects xylem traits that determine xylem efficiency and vulnerability. Nonetheless, seasonal variability of elevated CO2 (eCO2) effects on tree functioning under drought remains largely unknown. To address this knowledge gap, 1-year-old aspen (Populus tremula L.) trees were grown under ambient (±445 ppm) and elevated (±700 ppm) CO2 and exposed to an early (spring/summer 2019) or late (summer/autumn 2018) season drought event. Stomatal conductance and stem shrinkage were monitored in vivo as xylem water potential decreased. Additional trees were harvested for characterization of wood anatomical traits and to determine vulnerability and desorption curves via bench dehydration. The abundance of narrow vessels decreased under eCO2 only during the early season. At this time, xylem vulnerability to embolism formation and hydraulic capacitance during severe drought increased under eCO2. Contrastingly, stomatal closure was delayed during the late season, while hydraulic vulnerability and capacitance remained unaffected under eCO2. Independently of the CO2 treatment, elastic, and inelastic water pools depleted simultaneously after 50% of complete stomatal closure. Our results suggest that the effect of eCO2 on drought physiology and wood traits are small and variable during the growing season and question a sequential capacitive water release from elastic and inelastic pools as drought proceeds.

Hydrological and climate intensification induces conservative behavior in the Hydrochorea corymbosa xylem production in a Central Amazon floodplain forest

“…The Dh of H. corymbosa was larger than that found for other diffuse-porous species (Zimmermann et al, 2021;Lauriks et al, 2022). However, trees in this species could have other strategies for protecting their hydraulic tissues, like multiple vessels, which provide greater embolism safety, because the increase in hydraulic integration is associated with drier sites (von Arx et al, 2013;Rodrıǵuez-Ramıŕez et al, 2023).…”

Comparative Analysis of the Wood Metabolites of Three Poplar Clones Using UPLC-Triple-TOF-MS

“…Molecules 2023, 28, 7024 2 of 16 and ecosystem maintenance [19]. However, numerous internal and external factors influence the yield and quality of poplar wood, including genetic origin, a variety of biotic (e.g., pathogen infection and insect attack) and abiotic (e.g., cold, heat, flooding, drought and salinity) stresses [5,9,[20][21][22][23][24][25][26]. Therefore, based on the study of the molecular and biochemical mechanisms that control wood formation, various genetically modified poplar clones with the particular traits (e.g., adapted to specific environmental stresses, improved wood properties) are bred that will undoubtedly play a critical role in the economics and ecology in woody species.…”