Cryopreservation of conditionally dormant orthodox seeds of Betula pendula.

摘要

To evaluate the feasibility of long-term cryopreservation of Polish provenances of silver birch (Betula pendula), the sensitivity of conditionally dormant seeds to extreme desiccation and/or the ultra-low temperature of liquid nitrogen (LN; -196 degrees C) was evaluated. The critical water content (WC) of desiccated seeds and the high-moisture freezing limit of seeds desiccated or moistened to various WCs and frozen for 24 h or for 2 years in LN was also determined. Germination tests revealed no critical WC for seeds [to 0.02 g H₂O g-1 dry mass (g g-1)]. Seeds tolerated freezing in LN within specific safe range of WC 0.02-0.23 g g-1 (nuts). Seeds desiccated to the safe WC and stored in LN for 2 years had similar or higher germination as seeds stored at -3 degrees C for 2 years, depending on provenance. Therefore, long-term cryopreservation of B. pendula seeds in gene banks is feasible.