MATURATION AND DESICCATION OF SOMATIC EMBRYOS OF CYCLAMEN PERSICUM

With the aim of achieving storable somatic embryos of Cyclamen persicum, different desiccation conditions and two rehydration methods have been tested.
In addition, elevated sucrose concentration and polyethylene glycol (PEG 1500) have been applied during differentiation in order to find appropriate maturation conditions.
Somatic embryos were dried above saturated salt solutions adjusting different relative humidities (RH) in desiccators.
After drying a four-hour-prehydration-treatment in 98 % RH was performed.
The method used thereafter for rehydration was most important for subsequent germination.
Only after imbibition in liquid hormone-free medium tubers, cotyledons, and roots were formed.
Embryos dried slowly to moisture contents of 24 % and higher were able to germinate.
However, drying in decreasing RHs (91 – 57 – 18 %) resulted in very low water contents of about 12%, which is comparable to that found in seeds.
When applying decreasing RHs, somatic embryos with high dry matter content showed germination rates of up to 60 %. However, depending on the quality of somatic embryos strong differences were observed between experiments.
Germinating embryos formed bigger tubers than non-dried controls and developed cotyledons of better quality.
Treatment with 60 g/l sucrose during the three weeks of differentiation resulted in an increased number of single somatic embryos with higher dry matter content and improved desiccation tolerance.