Intra-Relations of Biochemical Profiles Defining the Germination Potential of Medium-Term Cold-Stored Maize (Zea mays L.) Seeds

Understanding the biochemical networks governing seed longevity is essential for germplasm conservation. Integrating germination potential with biochemical profiling elucidates metabolic transitions during decadal cold storage. As phenotypic evidence of ageing, extended cold storage induces a uniform decline in germination energy, reaching a terminal “floor effect” characterised by the complete exhaustion of repair-and-defence strategies, whilst residual germination capacity averages 21%. Metabolic profiling reveals that prolonged storage causes systemic decoupling of the protein–sugar axis, leading to the loss of protein-dependent vigour. The structural collapse of the proteomic architecture—manifested by the decoupling of embryo albumin-led coordination and endosperm α-zein dynamics—induces a transition to a low-vigour state, paralleled by carbohydrate shifts consistent with glassy matrix destabilisation, implicitly linking the displacement of sucrose-dominated stability to the molecular crowding of reducing sugars. Re-anchoring germination potential from primary metabolic drivers to soluble-free phenolics prompts a compensatory antioxidant reorganisation; under conditions of phenolic matrix degradation and carotenoid exhaustion, the observed stability of total antioxidant capacity likely reflects scavenging sustained by phenolic degradation products rather than native, intact protective mechanisms. Ultimately, seed ageing manifests as a genotype-specific systemic reconfiguration of biochemical coordination, where the physiological state of the cytoplasmic matrix and the maintenance of redox homeostasis determine residual viability, thereby defining the critical benchmarks for germplasm longevity.