ALGINATE ENCAPSULATION TECHNIQUE AND CRYOGENIC PROCEDURES FOR LONG-TERM STORAGE OF THE TROPICAL FOREST TREE GUAZUMA-CRINITA MART. IN-VITRO CULTURES

Long-term storage of the tropical forest tree Guazuma crinita Mart. fo llowing alginate encapsulation technique and cryogenic procedures was attempted. Shoot tips excised from in vitro plantlets were encapsulate d in calcium alginate beads and stored on different substrates at 12, 20, and 25 degrees C. Viability was retained when encapsulated shoot t ips were stored on substrate containing only water solidified with 1% (w/v) agar. Percentage of viability 12 months after storage was 90% at 25 degrees C and 70% at 20 degrees C. For cryogenic experiments, shoo t tip, nodal segment, root tip, and adventitious bud cluster explants were stored in liquid nitrogen following 4 cryopreservation methods: ( 1) simple freezing, (2) rapid freezing, (3) slow pre-freezing, and (4) encapsulation/dehydration method. High survival rates (about 80%) wer e achieved when the adventitious bud cluster explants were exposed to a cryoprotectant mix solution containing w/v), 25% glycerol, 15% sucro se, 15% ethylene glycol, 13% dimethyl sulfoxide, and 2% polyethylene g lycol (4,000), at 25 degrees C for 15-60 min prior to storage in liqui d nitrogen.