Pear seeds retain viability after liquid nitrogen immersion
2001
Reed, B.M. | Schwanke, S. | Shala, R.
Cryopreservation in liquid nitrogen (LN) is relatively routine for many small, desiccation-tolerant (orthodox) seeds. Seeds of Pyrus species are considered orthodox but have not been evaluated for LN storage. Seeds of freshly collected P. communis L. ('Bosc') were evaluated for germinability and by TZ staining after exposure to four LN treatments: 1) direct immersion and direct removal; 2) direct immersion and 1 minute in LN vapor phase before removal; 3) 2 minutes in vapor phase before immersion and direct removal; and 4) 2 minutes in vapor phase before immersion and 1 minute in vapor phase before removal. Fresh 'Bosc' seed viability evaluated by TZ and greenhouse germination tests remained high (83% to 100%) following four types of LN treatments, compared to the controls (77% to 87%). Differences in 'Bosc' seed viability were small and TZ results showed no significant differences among the LN treatments. Direct LN immersion and removal resulted in significantly more greenhouse-germinated 'Bosc' seeds than the other treatments and fewer control seeds germinated than any LN treated seeds. Fresh 'Bosc' seed cryopreserved at 7.9% moisture exhibited high germinability by both TZ and germination tests. LN exposure caused no physical damage to the seeds.
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