Seed Germination of Lilium ledebourii (Baker) Boiss. after Cryopreservation

Seeds or plant organs are usually used as the materials for the long-term cryopreservation. The aim of this study is to investigate the possibility of seed cryopreservation of Lilium ledebourii (Baker) Boiss. as an endemic and endangered species because of genetic erosion. To evaluate seed potentials for the cryopreservation, four treatments including vitrification, 30% glycerol, desiccation and encapsulation-dehydration were applied on seeds before immerging in the liquid nitrogen (-196˚C) for a week. Then, seeds were removed from liquid nitrogen and exposed to heat shock (42˚C water bath), washed with the distilled water and eventually, sown in petri-dishes containing tissue papers. Some criteria including seed germination percent, root and shoot length values, root/shoot length ratio and seed vigor index were recorded and statistically analyzed after four weeks. Data of germination was converted to an arc-sine transformation prior to the analysis of variance. Results showed that germination percentages were 97.50, 97.43, 94.86 and 69.47% for 30%-glycerol, vitrification, desiccation, and encapsulation-dehydration treatments, respectively. They were not significantly different from control seeds (89.33%). On the other hand, other germination attributes of seeds almost showed no significant differences in comparison with control treatment in most treatments. In addition, 30%-glycerol, vitrification and desiccation experienced the highest amounts of germination attributes whereas they showed no significant differences with the control treatment in most qualities. In contrast, the encapsulated seeds showed the lowest amounts in germination indices though they had no significant differences with control treatment (except germination rate). Most of germination attributes of encapsulated seeds were significantly lower than the other cryogenic treatments. Both 30% glycerol and desiccation treatments showed some advantages over vitrification method. However, desiccation was the best treatment because it does not need any chemical substances. It was concluded that the cryopreservation technique is an important approach for the long-term preservation of the seeds of this endangered species.