Functional traits related to regeneration responses to the environment are highly determinants of distribution patterns of plant communities. A large body of studies on seed traits suggests that regional climate may act as a strong filter of plant recruitment; however, few studies have evaluated the relative importance of seed traits and environmental filters for seed persistence at the population level. We tested the role of seed mass, water content and desiccation tolerance, as well as the germination time as proxies for seed tolerance to environmental filters (water deficit, heat shock and high temperatures) by comparing the response of tree species co-occurring in savannas located in different regions: Cerrado biome of Central Brazil and the Rio Branco savannas of northern Brazil. Seeds collected in savannas of Rio Branco showed a higher tolerance to environmental filters than those collected in savannas of the Cerrado. While the germination percentages largely varied in response to the treatments, the germination times were virtually unaffected by them, irrespective of seed origin, seed mass and water content. At the population level, the regional environment was a key determinant of seed tolerance to stress, irrespective of seed traits. Germination time was shown to represent a conservative seed trait and more linked to a species-specific germination strategy than to regional characteristics. Our results suggest that recruitment patterns of Cerrado savannas may be more impacted than Rio Branco savannas by the climate scenarios predicted for the future.

中文翻译：

---

区域气候和种子性状如何在塑造稀树草原种子的压力耐受性方面相互作用？

与环境再生反应相关的功能性状是植物群落分布模式的高度决定因素。大量关于种子性状的研究表明，区域气候可能是植物补充的强大过滤器；然而，很少有研究评估种子性状和环境过滤器在种群水平上对种子持久性的相对重要性。我们通过比较稀树草原中同时出现的树种的反应，测试了种子质量、水分含量和耐干燥性以及发芽时间作为种子对环境过滤器（缺水、热休克和高温）耐受性的代理作用。分布在不同的地区：巴西中部的塞拉多生物群落和巴西北部的里约布兰科稀树草原。在里约布兰科稀树草原采集的种子对环境过滤器的耐受性比在塞拉多稀树草原采集的种子更高。虽然发芽率因处理而有很大差异，但发芽时间几乎不受它们的影响，与种子来源、种子质量和含水量无关。在种群水平上，区域环境是种子耐受压力的关键决定因素，与种子性状无关。发芽时间被证明代表了一种保守的种子性状，并且与特定物种的发芽策略比与区域特征更相关。我们的研究结果表明，未来气候情景对塞拉多稀树草原的补充模式可能比里约布兰科稀树草原的影响更大。