Characterization of the Second Generation Cryopreserved Dendrobium Bobby Messina Using Histological and RAPD Analyses

摘要

This study was conducted to detect the morphological, histological and moleculardiff erences in the second generation of the PVS2 cryopreserved DendrobiumBobby Messina [DBM] (18 months old culture) plantlets. Morphological analysesindicated that similarities and diff erences in cryopreserved DBM plantlets comparingto control stock culture based on selected morphological criteria. Morphologicalcriteria, such as root length, number of shoot per explant and shoot length displayeddiff erences, while the other three criteria, leaf diameter, leaf length and PLBs sizewere similar in cryopreserved compared to the control stock culture plant. Higheramount of homogenous cell population and denser cytoplasm were observed incryopreserved PLBs compared to control stock culture PLBs based on histologicalanalysis. This suggests the existance of somatic embryogenesis developmentmechanism taking place during the recovery and regeneration of the cryopreservedPLBs. However, RAPD analyses based on 10 primers indicated that cryopreservedDBM regenerated from vitrifi cation method generated a total of 20 to 39.9%polymorphic bands as compared to stock culture indicating potential somaclonalvariation. Hence, an increase percentage of polymorphics bands in cryopreservedplantlets 18 months post cryopreservation as compared to previous report of 10%polymorphic bands in cryopreserved DBM 3 months post cryopreservation.