Classification of dormancy types and breakout conditions in Reynoutria sachalinensis exhibiting seed dormancy polymorphism

Reynoutria sachalinensis is an herbaceous plant that has gained attention as a promising functional ingredient in bio-health. However, information on the propagation of this plant remains limited, and information on the germination and dormancy characteristics of R. sachalinensis seeds native to Korea is yet to be established. This study aimed to determine the optimal method for breaking dormancy by classifying the dormancy types in R. sachalinensis seeds collected from Ulleungdo. Initial observations revealed that R. sachalinensis seeds exhibited water permeability and fully developed embryos. However, further investigation into seed dormancy was warranted due to the low germination percentage of less than 20%. To address this dormancy, a cold stratification treatment lasting four weeks was employed, which confirmed the presence of physiological dormancy (PD) in R. sachalinensis seeds. Additionally, prolonged after-ripening, without any special treatment, led to the loss of dormancy. Both treatments demonstrated that the dormancy of R. sachalinensis seeds could be overcome by alternative methods for non-germinated seeds. Accordingly, scarification was used to treat seeds whose dormancy was broken by after-ripening, and all viable seeds germinated. Therefore, it is assumed that R. sachalinensis seeds have two types of PD—non-deep and intermediate, exhibiting polymorphism as an adaptive strategy to thrive in challenging environments. Through this study, the scope of industrial use can be expanded based on stable and uniform seedling production by establishing conditions that efficiently break dormancy in R. sachalinensisseeds that exhibit polymorphism.