Seed size coupled with environmental effects on the level of physiological dormancy in <i>Acer mono</i> from different geographic provenances

BACKGROUND AND AIMS: The level of seed dormancy regulates germination timing, which is an adaptive differentiation that hedges risks against unpredictable and variable environments across a species's geographic range. The adaptive differentiation is significantly influenced by a combination of local environmental and intraspecific variation in seed traits. However, the relative importance of these influencing factors varies considerably among various geographic provenances of the same species. The objective of this study is to assess the association between level of dormancy and key environmental factors and intraspecific seed traits for the same species from different geographic provenances (climatic regions), and consequently, to predict how the species may react in the future climate change. METHODS: Seeds of widely distributed species Acer mono were collected from six geographic provenances along a latitudinal gradient in China. We employed a multi-factorial experimental design, treating seeds with gibberellin (multiple concentrations), cold/warm stratification (varying durations), dry after-ripening, and isolated embryo culture. Key morphometric (e.g., size, weight) and quality traits of seeds were measured. Germination responses were analyzed using Generalized linear models (binomial distribution) and Kruskal-Wallis. Multivariate relationships between seed traits and environmental factors were examined using Principal component analysis. KEY RESULTS: Seeds from higher-latitude geographic provenances (cold/dry) were larger and exhibited nondeep physiological dormancy (PD) broken by shortened stratification (40-120 days of cold (5 °C) or warm (15 °C) stratification), gibberellin, dry after-ripening, or embryo isolation, consistent with adaptive differentiation for rapid germination in the short growing season. Seeds from lower-latitude geographic provenances (warm/wet) displayed intermediate PD, requiring 150 days of cold stratification (5 °C) for release. CONCLUSIONS: This study provides empirical evidence that environmental gradients shape intraspecific variation in seed dormancy and traits in Acer mono, thereby enhancing our capacity to predict the species' regenerative potential via seeds under global climate change.