Canada Research Chair in Forest Genomics, Institute for Systems and Integrative Biology, Université Laval, Québec, QC G1V 0A6, Canada; Forest Research Centre, Département des sciences du bois et de la forêt, Université Laval, Québec, QC G1V 0A6, Canada; Natural Ressources Canada, Canadian Forest Service, Laurentian Forestry Centre, 1055 rue du P.E.P.S., P.O. Box 10380, Stn. Sainte-Foy, Québec, QC G1V 4C7, Canada.
Canada Research Chair in Forest Genomics, Institute for Systems and Integrative Biology, Université Laval, Québec, QC G1V 0A6, Canada; Natural Resources Canada, Canadian Forest Service, Canadian Wood Fibre Centre, 1055 rue du P.E.P.S., P.O. Box 10380, Stn. Sainte-Foy, Québec, QC G1V 4C7, Canada.
Sci Total Environ. 2024 May 1;923:171174. doi: 10.1016/j.scitotenv.2024.171174. Epub 2024 Feb 23.
Understanding how trees prioritize carbon gain at the cost of drought vulnerability under severe drought conditions is crucial for predicting which genetic groups and individuals will be resilient to future climate conditions. In this study, we investigated variations in growth, tree-ring anatomy as well as carbon and oxygen isotope ratios to assess the sensitivity and the xylem formation process in response to an episode of severe drought in 29 mature white spruce (Picea glauca [Moench] Voss) families grown in a common garden trial. During the drought episode, the majority of families displayed decreased growth and exhibited either sustained or increased intrinsic water-use efficiency (iWUE), which was largely influenced by reduced stomatal conductance as revealed by the dual carbon‑oxygen isotope approach. Different water-use strategies were detected within white spruce populations in response to drought conditions. Our results revealed intraspecific variation in the prevailing physiological mechanisms underlying drought response within and among populations of Picea glauca. The presence of different genetic groups reflecting diverse water-use strategies within this largely-distributed conifer is likely to lessen the negative effects of drought and decrease the overall forest ecosystems' sensitivity to it.
了解树木在严重干旱条件下如何优先考虑碳增益，而牺牲对干旱脆弱性的影响，对于预测哪些遗传群体和个体将对未来的气候条件具有弹性至关重要。在这项研究中，我们研究了生长、树木年轮解剖结构以及碳和氧同位素比值的变化，以评估 29 个成熟的白云杉（Picea glauca [Moench] Voss）家系在一个共同花园试验中对严重干旱事件的敏感性和木质部形成过程。在干旱期间，大多数家系的生长都有所减少，表现出持续或增加的内在水分利用效率（iWUE），这主要是由于双碳-氧同位素方法揭示的气孔导度降低所致。在对干旱条件的响应中，在白云杉种群中检测到不同的水分利用策略。我们的研究结果揭示了在 Picea glauca 种群内和种群间干旱响应的普遍生理机制存在种内变异。在这种广泛分布的针叶树中，存在反映不同水分利用策略的不同遗传群体，这可能会减轻干旱的负面影响，并降低整个森林生态系统对干旱的敏感性。
