ALGINATE-ENCAPSULATED TECHNOLOGY FOR THE PROPAGATION OF THE TROPICAL FOREST TREES - CEDRELA-ODORATA L., GUAZUMA-CRINITA MART., AND JACARANDA-MIMOSAEFOLIA DON,D

The possibility for encapsulation of shoot-tips or axillary buds in th e production of artificial seeds of Cedrela odor ata L., Guazuma crini ta MART., and Jacaranda mimosaefolia D. DON. was tested. High rate of bud emergence and shoot growth were achieved in vitro on substratum co ntaining nutrients but, on substratum containing water only, the bud e mergence from beads and later shoot growth were very poor. In an attem pt to improve the plant regeneration rate from artificial seeds on sub stratum without nutrients (to diminish the risk of contamination under non-aseptic conditions), 2 types of beads with a single or double lay er were tested. The best result was obtained with double layered beads containing medium at a concentration of 1,000% (w/v) supplemented wit h 0.5% (w/v) activated charcoal in the inner layer, and at concentrati on of 100% (w/v) in the outer layer. After 6 weeks of incubation on wa ter substratum solidified with 1% (w/v) agar under In vitro conditions , high rates of bud emergence and shoot growth were achieved: 60% and 60% for C. odorata, 100% and 80% for G. crinita, and, 100% and 100% fo r J. mimosaefolia, respectively. However, when artificial seeds were d irectly sowed on nutrient-free substratum under non-aseptic conditions , the percentage of beads converted into plants was 6.7%, 3.3%, and 31 .7% for C. odorata, G. crinita and J. mimosaefolia, respectively. But, when artificial seeds of C. odorata and G. crinita were incubated in vitro for about 1 week before sowing on non-sterilized substratum, the plant regeneration rate was increased to 28.6% and 100%, respectively .