Evaluation of Seed Germination of Six Rare Species following Low Temperature Stress (Cryopreservation).

Cryopreservation is one way to preserve rare, endangered species. However, during the cryopreservation process, plant cells undergo considerable stress, which may lead to cell death. In our work, orthodox seeds of six rare species were cryopreserved: , , , , , and . Short-term cryopreservation (14 days) stimulated germination of all species studied. Prolonged cryopreservation (70 days and more) decreased the germination of all seeds except . The decrease in germination progressed over time as a result of the cumulative stress of cryopreservation rather than the initial stress. To stimulate germination, seeds were stratified and treated with GA, KNO, NaOH, and HO. After four years of seed cryopreservation, it was possible to obtain seedlings of all the species studied with 30 days of stratification and 180 days of germination. After five years of cryopreservation and seed treatment with 30% NaOH for one hour, the best germination was obtained in and . After treatment with 5% HO for 20 min, the best germination was obtained in , , and . seeds germinated in all the aforementioned experiments. has a non-deep physiological dormancy and is the most widespread and drought-tolerant species studied. The best habitat adaptation and stress tolerance correlated with this species'cryotolerance. was recommended for further cryopreservation, while storage protocols for the other species studied need further improvements.