INRA, UMR1202 Biodiversité Gènes et Communautés, Cestas, France.
J Evol Biol. 2011 Jul;24(7):1442-54. doi: 10.1111/j.1420-9101.2011.02277.x. Epub 2011 Apr 21.
We assessed the adaptive potential of seed and leaf phenology in 10 natural populations of sessile oak (Quercus petraea) sampled along two altitudinal transects using common garden experiments. Population differentiation for both phenological traits was observed with high-altitude populations germinating and flushing later than low altitude ones. However, high genetic variation and heritability values were also maintained within populations, despite slightly decreasing for dates of leaf unfolding with increasing altitude. We suggest that biotic and abiotic fluctuating selection pressures within populations and high gene flow are the main mechanisms maintaining high genetic variation for these fitness related traits. Moreover, changes in selection intensity and/or selection pressures along the altitudinal gradient can explain the reduction in genetic variation observed for leaf phenology. We anticipate that the maintenance of high genetic variation will be a valuable resource for future adaptation of sessile oak populations undergoing an upslope shift caused by climate change.
我们使用了田间实验的方法，在沿着两条海拔梯度的 10 个自然栎种群中评估了栎树（Quercus petraea）种子和叶片物候的适应潜力。我们观察到，在这两个物候特征上，高海拔种群的萌发和展叶时间都晚于低海拔种群。然而，尽管随着海拔的升高，叶片展开的日期略有推迟，但种群内仍然保持着较高的遗传变异和遗传力值。我们认为，种群内的生物和非生物波动选择压力以及高基因流是维持与适应相关性状高遗传变异的主要机制。此外，在海拔梯度上选择强度和/或选择压力的变化可以解释在叶片物候方面观察到的遗传变异的减少。我们预计，在气候变化导致栎树种群向上迁移的情况下，维持高遗传变异将是栎树种群未来适应的宝贵资源。
