Solving Seed Germination Problems in Conservation Collections

Solving germination problems: careful excision of the pericarp above the embryo can overcome physiological dormancy in tropical grasses

Millennium Seed Bank (MSB) collections are tested for viability after 1 month of storage, using a germination test, and then retested every 5 or 10 years subsequently.  To advise potential users of the collections of the simplest possible protocol for turning seeds into plants, we strive to achieve maximum germination with the simplest set of germination conditions. A Germination Predictor which operates at the genus level and is linked to the Seed Bank Database (SBD) is used to assess the most likely conditions required for germination based on our own historical records. Information from other sources including the Seed Information Database (SID), climate data, the mainstream scientific literature and partners is also used to refine the selection of germination conditions especially for new species.

Approximately 50% of the MSB collections achieve a satisfactory result using the above approach but for the remaining, problematic collections, family-based or thematic approaches are used to solve germination problems. Successful approaches have included the application of factorial experiments where the combination of treatments applied is informed by various factors including seed structure, life form, ecology, climate of origin etc. Problematic families and genera that have received particular attention include: Rubiaceae, Rosaceae, Labiatae, Cucurbitaceae, Gentianceae, Guttiferae, Caryophyllaceae, Poaceae and Plantaginaceae.

Germination problems have been solved in > 2000 species and novel techniques for overcoming seed dormancy in certain groups have been identified including the application of a surgical incision to the pericarp to remove physiological dormancy in tropical grasses. In some families, for example Goodeniaceae, collaborative studies have been carried out with visiting international partners. Knowledge gained from these approaches has been disseminated via the Seed Information Database, papers at international conferences, scientific journals, Samara and training materials.

Future investigations of collection-based seed germination problems will be targeted wherever possible to validate and improve the predictive tool of germination requirements for MSB collections.