It is widely assumed that seed mass, as a proxy of both dispersability and competitiveness, can affect community composition and diversity. Numerous studies have validated the influence of seed mass at the interspecific level. However, little is known about patterns of among-population variation in seed mass (APVSM), which may influence a species’ persistence under climate change. We characterized the naturally occurring variation in seed mass among populations across 190 Tibetan plant species (2,503 populations). We tested for relationships between APVSM and plant life-history traits (mean seed mass, seed dormancy type, seed dispersal mode, life form, and pollination system) and an environmental factor, elevation. We also tested patterns of phylogenetic signal in APVSM and identified the lineages (clades) with an exceptionally high or low APVSM. We found that APVSM varied > 5-fold among species, ranging from 0.085 in Bromus sinensis to 0.447 in Anaphalis flavescens. Furthermore, wind-dispersed species tended to have greater APVSM. Finally, we found that APVSM exhibited a significant phylogenetic signal (i.e., closely related species were more or less variable in their seed size than would be expected by chance) that was driven by a few major lineages. Clades with significantly less APVSM included Brassicaceae, Campanulaceae, Ranunculaceae (including Thalictrum, Trollius, Aconitum and Anemone), Roegneria, Rumex. Clades with significantly greater APVSM included Bignoniaceae, Lamiaceae, Orobanchaceae, Anaphalis, Cotoneaster and Sorbus. In summary, our study suggested that APVSM is partly due to trade-offs in evolutionary history and its associations with other life-history traits.

人们普遍认为，种子量作为分散性和竞争力的代名词，会影响社区的组成和多样性。许多研究已在种间水平上验证了种子质量的影响。但是，人们对种子量之间种群间变异的模式（APVSM）知之甚少，这可能会影响物种在气候变化下的持久性。我们表征了190种藏族植物物种（2,503种）的种群中种子质量的自然变化。我们测试了APVSM与植物生命历史特征（平均种子质量，种子休眠类型，种子传播模式，生命形式和授粉系统）之间的关系以及环境因子，海拔之间的关系。我们还测试了APVSM中的系统发生信号模式，并确定了具有异常高或低APVSM的谱系（进化枝）。中华凤（Braphamus flavescens）中中华（Bromus sinensis）至0.447 。此外，风散性物种倾向于具有更高的APVSM。最后，我们发现APVSM表现出由几个主要谱系驱动的重要系统发生信号（即，密切相关的物种的种子大小或多或少比偶然所预期的多）。APVSM显着降低的枝条包括十字花科，桔梗科，毛ace科（包括Thalictrum，金莲花，乌头和海葵），Roegneria，Rumex。APVSM明显较高的枝包括紫n科，唇形科，Orobanchaceae，Anaphalis，枸子和山梨。总而言之，我们的研究表明，APVSM的部分原因是进化史及其与其他生活史特征之间的联系。