Frozen storage stimulates the formation of embryo-like structures and elongating shoots in explants from mature Larix decidua and L. x eurolepsis trees

Branches were collected from a Larix decidua and a L. x eurolepis tree, both 36 years old, in mid-winter. These branches were placed in freezers at –5°C, –10°C, and –18°C. Primordial shoot explants were excised after 2 to 9 months of frozen storage. The material remained viable at all three temperatures for at least 9 months. The frozen storage stimulated formation of embryo-like structures that were capable of forming shoots with elongated stems.Abbreviations 1/2 LM half strength Litvay medium