Exploring novel and innovative storage strategies for recalcitrant seeds

Ex situ seed storage plays a critical role in conserving plant genetic resources threatened by climate change and habitat loss. Orthodox seeds, which comprise the majority of seed-producing plants, tolerate desiccation and freezing, allowing long-term storage. Their survival is attributed to metabolic quiescence and cellular stabilization during drying. In contrast, recalcitrant seeds are highly sensitive to drying and chilling, which limits their storage using conventional seed banking methods. Recent advances focus on overcoming these challenges through embryo excision, in vitro culture and cryopreservation including vitrification, and encapsulation-dehydration, although these techniques are labour-intensive and constrained in scale. Differences in desiccation sensitivity between tissues, such as embryonic axes and cotyledons, highlight the need for comprehensive preservation strategies. In recalcitrant seeds with epicotyl dormancy, the epicotyl elongates, sometimes forming a swollen tuber-like structure, then pauses growth while functioning independently of the seed, at which point it can be excised, dried and stored at about -20 °C or under cryogenic conditions. Integrating physiological, molecular and ecological knowledge is essential for developing innovative, tissue-specific protocols to improve seed longevity and conservation outcomes, thereby enhancing biodiversity preservation and agricultural resilience under rapidly changing environmental conditions.