Survival of Chlorophyllous and Nonchlorophyllous Fern Spores through Exposure to Liquid Nitrogen

Thirty-three species of ferns with nonchlorophyllous spores and five species with chlorophyllous spores were studied in regard to their ability to survive exposure to liquid nitrogen (LN).Air dried spores showed no inhibition of germination after LN exposure when planted on soil or growth medium.Spores of three species that were stored for 75 months either at 4°C, -20°C» or in LN showed no decrease in viability over that time, and spores of four other species were maintained successfully for 52 months in LN, Fresh chlorophyllous spores that were air dried, dried over silica gel, or prepared with the encapsulation dehydration procedure also showed good survival through desiccation and LN exposure.Spores of Osmunda regalis germinated well after 18 months of LN storage.These results indicate that both nonchlorophyllous and chlorophyllous spores are candidates for long-term germplasm storage at low temperatiires, including storage in LN.