Cryopreservation of Cosmos atrosanguineus shoot tips by a modified encapsulation/dehydration method

摘要

A new technique for shoot tip encapsulation in strips is described. Shoot tips of Cosmos atrosanguineus encapsulated in strips of 3% sodium alginate were pretreated on media of increasing sucrose concentration and subjected to dehydration followed by rapid cooling in LN. Optimal pretreatment of encapsulated shoot tips consisted of 72 h on 0.3M sucrose followed by 96 h on 0.75M sucrose. Dehydration for 7-9 h prior to rapid cooling in LN reduced water content to 0.15 - 0.16 g H2O g d.w.(-1) and gave 83-92% survival. Survival of frozen shoot tips was indicated by cellular growth and greening of the apical region after 14-21 days. Shoot regeneration occurred at 6-8 weeks. Plantlets regenerated from frozen shoot tips showed no phenotypic variation. [References: 22]