Variation in photosynthetic performance and hydraulic architecture across European beech (Fagus sylvatica L.) populations supports the case for local adaptation to water stress

Abstract

The aim of this study was to provide new insights into how intraspecific variability in the response of key functional traits to drought dictates the interplay between gas-exchange parameters and the hydraulic architecture of European beech (Fagus sylvatica L.). Considering the relationships between hydraulic and leaf functional traits, we tested whether local adaptation to water stress occurs in this species. To address these objectives, we conducted a glasshouse experiment in which 2-year-old saplings from six beech populations were subjected to different watering treatments. These populations encompassed central and marginal areas of the range, with variation in macro- and microclimatic water availability. The results highlight subtle but significant differences among populations in their functional response to drought. Interpopulation differences in hydraulic traits suggest that vulnerability to cavitation is higher in populations with higher sensitivity to drought. However, there was no clear relationship between variables related to hydraulic efficiency, such as xylem-specific hydraulic conductivity or stomatal conductance, and those that reflect resistance to xylem cavitation (i.e., Ψ(12), the water potential corresponding to a 12% loss of stem hydraulic conductivity). The results suggest that while a trade-off between photosynthetic capacity at the leaf level and hydraulic function of xylem could be established across populations, it functions independently of the compromise between safety and efficiency of the hydraulic system with regard to water use at the interpopulation level.

Xylem embolism refilling and resilience against drought‐induced mortality in woody plants: processes and trade‐offs

“…This information would be very valuable for future research efforts aimed at breeding and selecting cultivars and genotypes of crops and forest species able to cope with projected increase in frequency/intensity of drought and heat waves. Current research is mainly focused on selecting traits conferring resistance or tolerance to drought stress, like embolism resistance (Cochard et al 2008;Aranda et al 2015;Fichot et al 2015). Evidence accumulating around the role of embolism refilling might indeed suggest shifting the focus to traits conferring resilience to drought.…”

Metabolic Responses of Steppe Forest Trees to Altirude-Associated Local Environmental Changes

“…It has been studied intensively during recent years. Thus, Aranda et al (2015) showed significant physiological differences among six Fagus sylvatica populations adapted to specific local water availability. Zadworny et al (2015) established a strong seasonal variation in nitrogen concentration among roots of oak trees growing in two contrasting soil types.…”

Role of street trees in mitigating effects of heat and drought at highly sealed urban sites

“…Plant water status, water loss, and water usage are strongly related to diurnal and seasonal climatic factors, e.g., irradiance, temperature, and air humidity (Aranda et al, 2014;Osone et al, 2014) as well as edaphic factors, e.g., soil water supply (Roberts, Strain, & Knoerr, 1980;Sperry, 2000). Species differ in their sensitivity to water deficits and mechanisms for regulating the water flux by stomatal conductance (Roberts et al, 1980).…”