In Vitro propagation of enterolobium cyclocarpum (guanacaste) from nodal explants of axenic seedlings

Résumé 0

"Enterolobium cyclocarpum (Jacq.) Griseb. is a multipurpose leguminous tree, considered an endangered speciesbecause of overexploitation and the slow rates of natural propagation due to the intrinsic characteristics of the tree. An alternativeapproach to overcome this problem is the establishment of systems for its rapid, mass propagation. In this work, a protocol for invitro propagation of E. cyclocarpum using the axenic nodal segments obtained from in vitro germinated seedlings, wasinvestigated. The seeds collected from two Mexican communities were germinated both ex vitro and in vitro and the effect of apre-treatment of thermal scarification was evaluated. Seeds from only one community were selected for propagation experimentson the basis of lower genetic variability estimated by RAPD markers, due to the high variation in the responses observed inpooled seed lots, which probably reflects an effect of genotype. Nodal segments from seedlings were cultured on MS basalmedium supplemented with 30 g/L sucrose in the presence of different concentrations of 1-naphthaleneacetic acid (NAA) incombination with benzyladenine (BA) or kinetin (KIN). The highest multiplication rate (with an average of 4.75 shoots perexplant) was achieved when MS medium was supplemented with 2.2 µM BA and 10.7 µM NAA. Excised shoots were rooted onhalf-strength MS medium without growth regulators. The micropropagated plantlets were acclimatized and successfullytransferred to soil with a survival rate of 90%. These plantlets appeared morphologically similar to the mother plant and novariation was detected among them by the use of RAPD markers, which makes possible the use of this procedure for thepropagation clonal of this species"