GC-MS-Based Metabolic Profiling Identifies Candidate Endogenous Inhibitors Associated with the Physiological Component of Morphophysiological Dormancy in Spuriopinella brachycarpa (Kom.) Kitag. Seeds

Seeds of Spuriopinella brachycarpa (Kom.) Kitag., an economically valuable wild vegetable of the Apiaceae family, exhibit morphophysiological dormancy (MPD), which is characterized by underdeveloped embryos at dispersal, together with a physiological dormancy component that requires specific environmental cues for release. However, the endogenous chemical basis of this physiological component remains unclear. In this study, compounds associated with inhibitory activity were extracted from freshly harvested seeds using organic solvents of graded polarity (methanol, diethyl ether, petroleum ether, and ethyl acetate), and the inhibitory activity of each fraction was evaluated in heterologous bioassays using Chinese cabbage (Brassica rapa subsp. pekinensis) seeds. The methanol-phase extract exhibited the strongest inhibitory effect, reducing the germination percentage by 83.40% relative to the water control, followed by the diethyl ether extract (45.34% reduction), whereas the petroleum ether and ethyl acetate extracts showed only weak effects. GC-MS profiling of the extracts identified 65 compounds, predominantly organic acids, ketones, phenols, esters, and monoterpenes. Based on their relative abundance and previously reported germination inhibitory activities, acetic acid, palmitic acid, benzaldehyde, and thymol were tentatively identified priority candidate compounds associated with inhibitory activity. All compound identities are putative assignments based on NIST library spectral matching (match score > 80%), and their associations with inhibitory activity are correlative rather than causal. These findings provide the first systematic chemical characterization of compounds associated with inhibitory activity in S. brachycarpa seeds and a biochemical basis for understanding the physiological component of MPD, while establishing practical candidate targets for developing seed priming formulations and dormancy-breaking techniques. Further verification using authentic standards and direct bioassays on S. brachycarpa embryos is required to confirm the causal roles of these compounds.