The effects of preculture on plant regeneration from cryopreserved shoot tips of redwood (Sequoia sempervirens (D. Don.) Endl.)

The aim of the present study was to investigate the importance of the preculture conditions on the survival of redwood (Sequoia sempervirens (D. Don.) Endl.) shoot tips cryopreserved using a combined droplet-vitrification procedure. In vitro grown Sequoia plants were used for cryopreservation. Preculture was critical for the survival of shoot tips after cryopreservation. Among the different tested sugars and sugar alcohols (glucose, sucrose, mannitol and sorbitol), treatment with 0.5 M sucrose for 24 h was the most efficient one. One-step vitrification protocol with PVS2 for 30 minutes was efficient for shoot regeneration following cryopreservation. After rapid thawing and transfer of shoot tips on recovery medium, 67% growth recovery was observed. Plants produced from control and cryopreserved shoot tips were phenotypically similar.