Cryopreservation of orthodox seeds of Alnus glutinosa

We evaluated the sensitivity of orthodox seeds of black alder (Alnus glutinosa (L.) Gaertn.) to extreme desiccation and/or to the ultra-low temperature of liquid nitrogen (LN; -196 degrees C). The critical water content (WC) of desiccated seeds and the high-moisture freezing limit of seeds desiccated or imbibed to various WCs and frozen for 24 h or up to two years in LN was determined. Germination tests revealed that desiccation to 0.03 g H20.g(-1) dry mass was not detrimental to these seeds. Seeds tolerated LN freezing when the WC was 0.03-0.18 g H2O g(-1) dm (nuts). Seeds desiccated to this WC and stored in LN for two years showed similar germination as seeds stored at -3 degrees C for two years. Therefore, long-term cryopreservation of A. glutinosa seeds in genebanks is feasible.