Summary
Published in Tree Physiology 35(8): 864–878. https://doi.org/10.1093/treephys/tpv054
Climate-related variations in functional traits of boreal tree species can result both from physiological acclimation and genetic adaptation of local populations to their biophysical environment. To improve our understanding and prediction of the physiological and growth responses of populations to climate change, we studied the role of climate of seed origin in determining variations in functional traits and its implications for tree improvement programs for a commonly reforested boreal conifer, white spruce (Picea glauca (Moench) Voss).
We evaluated growth, root-to-shoot ratio (R/S), specific leaf area (SLA), needle nitrogen (Nmass), total non-structural carbohydrates (NSC) and photosynthetic traits of 3-year-old seedlings in a greenhouse experiment using seed from six seed orchards (SO) representing the different regions where white spruce is reforested in Québec. Height and total dry mass (TDM) were positively correlated with photosynthetic capacity (Amax), stomatal conductance (gs) and mesophyll conductance (gm). Total dry mass, but not height growth, was strongly correlated with latitude of seed origin (SO) and associated climate variables. Amax, gs, gm and more marginally, photosynthetic nitrogen-use efficiency (PNUE) were positively associated with the mean July temperature of the SO, while water use efficiency (WUE) was negatively associated. Maximum rates of carboxylation (Vcmax), maximum rates of electron transport (Jmax), SLA, Nmass, NSC and R/S showed no pattern. Our results did not demonstrate a higher Amax for northern seed orchards, although this has been previously hypothesized as an adaptation mechanism for maintaining carbon uptake in northern regions. We suggest that gs, gm, WUE and PNUE are the functional traits most associated with fine-scale geographic clines and with the degree of local adaptation of white spruce populations to their biophysical environments. These geographic patterns may reflect in situ adaptive genetic differences in photosynthetic efficiency along the cline.
Sector(s):
Forests
Categorie(s):
Scientific Article
Theme(s):
Forestry Research, Forests, Seeds and Forest Seedlings Production
Departmental author(s):
Author(s)
BENOMAR, Lahcen, Mohammed S. LAMHAMEDI, Isabelle VILLENEUVE, André RAINVILLE, Jean BEAULIEU, Jean BOUSQUET and Hank A. MARGOLIS
Year of publication :
2015
Format :
PDF available upon request
How to get the publication :
Keywords :
épinette blanche, vergers à graines, adaptation, échanges gazeux, migration assistée, changements climatiques, production de semences et de plants, article scientifique de recherche forestière, Picea glauca, white spruce, seed orchard, adaptation, photosynthetic parameters, assisted migration, climate change, seeds and forest seedlings production