Dry after-ripening affects seed dormancy and germination of Silene takeshimensis , an endemic plant of the Korean Peninsula

Silene takeshimensis (Caryophyllaceae) is endemic to the Korean Peninsula; however, information on its seed dormancy is scarce. Understanding the seed dormancy and germination characteristics of this endemic species is essential for elucidating its reproductive ecology and establishing effective seed propagation and conservation protocols. We investigated the germination responses of S. takeshimensis to temperature regimes (4/4–30/20°C), cold stratification (CS; 0–12 weeks at 4°C), GA ₃ treatment (0–1,000 mg L ^-1 for 24 hours), dry after-ripening (DAR; 0–12 weeks at room temperature) and seed storage at 1°C (5 or 20 months) to determine its dormancy status. The seeds have fully developed embryos and a permeable seed coat, ruling out morphological and physical dormancy. Final germination (FG) was significantly reduced at 4/4°C (< 5%), whereas mean germination time (MGT) decreased at relatively warm alternating temperatures (20/10–30/20°C). Although CS did not increase FG, it reduced MGT to within approximately one week. DAR for four and eight weeks significantly increased FG at 15/6°C, reaching 100 and 82%, respectively, and reduced MGT at 15/6°C (approximately 23 days), indicating the presence of non-deep PD in a portion of the seed population. However, germination remained lower at 15/6°C than 25/15°C, suggesting that some seeds may have been conditionally dormant under suboptimal thermal conditions. Furthermore, compared with freshly harvested seeds from the same seed collection, seeds stored dry at 1°C for eight months exhibited higher germination percentages at 15/6°C, indicating conditional dormancy in freshly harvested seeds. Freshly harvested S. takeshimensis seeds exhibited conditional dormancy under cooler incubation conditions, which was alleviated by short-term DAR or cold dry-storage.