1. Northward migration of trembling aspen will increase growth but reduce resistance to drought-induced xylem cavitation
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Inoue, Sahari, Dang, Qing-Lai, Man, Rongzhou, and Tedla, Binyam
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LI-COR Inc. -- Growth ,Scientific equipment and supplies industry -- Statistics -- Growth -- Physiological aspects -- Electric properties ,Hydrogeology -- Physiological aspects -- Electric properties ,Soil moisture -- Physiological aspects -- Electric properties ,Global temperature changes -- Physiological aspects -- Electric properties ,Carbon dioxide -- Statistics -- Physiological aspects -- Electric properties ,Company growth ,Biological sciences - Abstract
Tree migration to higher latitudes may occur in response to future changes in climate, exposing the trees to higher concentrations of carbon dioxide ([[CO.sub.2]]), new photoperiods, different levels of soil moisture, and other new conditions. These new conditions can influence the physiology, survival, and growth of trees. This study examined the interactive effects of [[CO.sub.2]], photoperiod, and soil moisture on the morphology and resistance to xylem cavitation in trembling aspen (Populus tremuloides Michx.). One-year-old seedlings, in greenhouses, were exposed to two [[CO.sub.2]] (ambient [[CO.sub.2]] 400 [micro]mol*[mol.sup.-1] or an elevated [[CO.sub.2]] 1000 [micro]mol*[mol.sup.-1]), four photoperiod regimes corresponding to latitudes 48[degrees]N (seed origin), 52[degrees]N, 55[degrees]N, and 58[degrees]N, and two levels of soil moisture (60%-75% and 13%-20% of field capacity) for one growing season. Seedling growth, leaf size, specific leaf area, biomass allocation, and xylem resistance to cavitation (water potentials for 20%, 50%, and 80% loss of hydraulic conductivity) were assessed. The seedlings under the longest photoperiod regime (58[degrees]N latitude) had greatest height and biomass but smallest specific leaf area. Under the elevated [[CO.sub.2]], however, the longest photoperiod regime significantly reduced xylem resistance to drought-induced cavitation compared with the photoperiod corresponding to 48[degrees]N. These results suggest that when migrating to higher latitudes, trembling aspen may grow faster but could become less resistant to drought and more prone to hydraulic failure during a drought spell. Keywords: climate change, tree migration, morphology, cavitation resistance. Un jour, les arbres pourraient migrer a des latitudes plus elevees en reponse aux changements clima-tiques, les exposant des concentrations plus elevees de [CO.sub.2] ([[CO.sub.2]]), a de nouvelles photoperiodes, a une humidite du sol differente et a d'autres conditions nouvelles. Les nouvelles conditions peuvent influencer la physiologie, la survie et la croissance des arbres. Cette etude s'est penchee sur les effets interactifs de la [[CO.sub.2]], de la photoperiode et de l'humidite du sol sur la morphologie et la resistance a la cavitation du peuplier faux-tremble aspen (Populus tremuloides Michx.). Des plants ages d'un an ont ete exposes a deux [[CO.sub.2]] ([[CO.sub.2]] ambiante de 400 [micro]mol*[mol.sup.-1] et [[CO.sub.2]] elevee de 1000 [micro]mol*[mol.sup.-1]), quatre regimes de photoperiodes correspondant a des latitudes de 48[degrees] (origine de la semence), 52[degrees]N, 55[degrees]N et 58[degrees]N, et deux conditions d'humidite du sol (60-75% et 13-20% de la capacite du champ) pendant une saison de croissance en serres. La croissance des plants, la taille des feuilles, la surface specifique des feuilles, les repartitions de la biomasse et la resistance du xyleme a la cavitation (potentiels hydriques pour 20, 50 et 80% de perte de conductivite hydraulique) ont ete evaluees. Les plants soumis a la plus longue photoperiode (latitude 58[degrees]N) presentaient la hauteur et la biomasse les plus elevees, mais la surface foliaire specifique la plus petite. À une [[CO.sub.2]] elevee, cependant, la photoperiode la plus longue reduisait significativement la resistance du xyleme a la cavitation induite par la secheresse comparativement a la photoperiode correspondant a une latitude de 48[degrees]N. Les resultats suggerent que lors de sa migration vers des latitudes plus elevees, le peuplier faux-tremble pourrait croître plus rapidement, mais devenir moins resistant a la secheresse et plus enclin a une insuffisance hydraulique durant un episode de secheresse. [Traduit par la Redaction] Mots-cles : changement climatique, migration des arbres, morphologie, resistance a la cavitation., Introduction The projected increases in global temperatures and changes in precipitation patterns will likely induce a northward migration of boreal trees by the end of this century (McKenney et al. [...]
- Published
- 2019
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