Sprouting by woody plants can increase species resilience to disturbance and foster regeneration during periods with little recruitment from seed. Though sprouting often plays a critical role in oak forest regeneration, there is little information available on sprouting capacity and sprout physiology at the seedling stage, particularly for new germinants. This study compared sprouting capacity and sprout photosynthesis of shoot-clipped germinants of two temperate oaks established in contrasting light environments. We studied the North American Quercus alba and the European Q. robur, both are in the section Quercus and appear to share similar biological and ecological requirements. Sprouting capacity for both species was enhanced under high light availability (29% more sprouts per plant), a response not previously noted for oak germinants. Seedling sprouts acclimated to high light with a 34% decrease in leaf area ratio, a 56% increase in leaf mass per area, and a 49% increase in the light-saturated maximum photosynthetic rate. Though both species appeared similarly adapted to shoot loss, a greater sprouting capacity (29% more sprouts per plant) and plant-level net photosynthesis (73% higher) was observed for Q. robur, regardless of light environment. As naturally regenerated oak seedlings in forest understories often experience disturbance or stress resulting in shoot loss or die-back, our results highlight the importance of the light environment during early plant development. Our comparison of temperate oaks from different continents should facilitate exchange of successful stand regeneration practices within the range of temperate oak forests.

中文翻译：

---

芽修剪的橡树（栎栎和Q. robur）的芽苗对不同的光照环境表现出形态和光合适应性

木本植物发芽可以增加物种对干扰的抵抗力，并在很少从种子中募集的时期促进再生。尽管发芽通常在橡树林再生中起关键作用，但很少有关于苗期发芽能力和发芽生理的信息，特别是对于新发芽剂。这项研究比较了在对比光照条件下建立的两种温带橡木的发芽生芽的发芽能力和发芽光合作用。我们研究了北美栎和欧洲栎，它们都在栎属部分中并且似乎具有相似的生物学和生态要求。在高光照条件下，这两种物种的发芽能力都得到增强（每株植物的新芽多出29％），这是橡树萌发剂以前没有注意到的反应。幼苗发芽适应高光，叶面积比减少34％，每面积叶质量增加56％，光饱和最大光合速率增加49％。尽管两种物种看起来都相似地适合于枝条损失，但是观察到罗伯Q. robur具有更高的发芽能力（每株植物多29％的芽）和植物水平的净光合作用（高73％）。，无论光线环境如何。由于森林地下的天然再生橡树幼苗经常受到干扰或胁迫，从而导致枝条损失或枯死，因此我们的结果突出了在植物早期发育过程中光环境的重要性。我们对来自不同大洲的温带橡木的比较应有助于在温带橡木林范围内交流成功的林分再生实践。