IMPROVEMENT OF Chrysanthemum x grandiflorum (Ramat.) Kitam. ENCAPSULATION-DEHYDRATION CRYOPRESERVATION PROTOCOL

To optimize the protocol, the shoot tips of Chrysanthemum x grandiflorum (Ramat.) Kitam. radiomutants have been cryopreserved using the encapsulation-dehydration technique, following different approaches. In the experiment the influence of abscisic acid - ABA (0; 10; 20 and 30 mu M), sucrose concentration (0.09; 0.25 and 0.5 M) and temperature (5 degrees C or 22 degrees C) during preculture were tested. Furthermore two dehydration methods, gradual and one-step, were considered. Since the best results were reported with 10 mu M ABA + 0.09 M sucrose at room temperature and gradual dehydration, only this combination was selected for the next desiccation-adjustment step. From the time of air desiccation under laminar air-flow applied (0; 1; 2; 3; 4 and 5 hours), 3 hours provided the best results. Due to the growth inhibition on the hormone-free medium, the addition of plant growth regulators during that phase was also tested, confirming the need to apply cytokinins into the medium.