Organogenic cultures were induced from zygotic embryo and megagametophyte explants of the Chiapas State (México) endangered cycad species, Dioon merolae De Luca Sabato & Vazquez Torres. The induction medium consisted of B5 major salts, Murashige and Skoog (1962) minor salts and organics, 400 mg/L glutamine, 100 mg/L arginine, 100 mg/L asparagine, 60 g/L, sucrose, 4 g gellan gum, and supplemented with 2,4- Dichlorophenoxyacetic acid (2,4-D) (0, 0.45, 2.26, 4.52, 9.05 ųM) and kinetin (0, 2.32, 4.60, 9.30, 13.90 ųM) arranged as a 5 x 5 factorial in a randomized block design. Cultures were maintained in darkness at 25°C, and callus was subcultured onto fresh medium at 4 week intervals. Callus initiation occurred on a wide range of plant growth regulators (PGR) combinations from megagametophyte explants. In comparison, callus initiation from explanted zygotic embryos occurred on few PGR combinations. Adventitious shoot induction occurred from callus on formulations with 4.60, 9.30, 13.90μM 2,4-D y con 9.05 µΜ K. Through the histological analysis of longitudinal sections of zygotic embryos were detected apical meristematic cells of the shoot and root and in megagametophytes the formation of elements similar to tracheids and coralloid roots. This technique has a great potential for preservation of the highly endangered cycads. Key words: Organogenesis/ Cycads/ Dioon merolae/ Danger Species / Histology/ ; A partir de explantes de embriones cigóticos y megagametofitos fueron inducidos cultivos organogénicos de Dioon merolae De Luca Sabato & Vázquez Torres, del estado de Chiapas (México) cícada en peligro de extinción. El medio de inducción Litz consistió en los macronutrientes del medio B5, los micronutrientes del medio MS (1962) y los compuestos orgánicos glutamina 400 mg/L, arginina 100 mg/L, asparagina 100 mg/L, sacarosa 60 g/L, gellan-gum 4 g, y suplementado con ácido 2,4-Diclorofenoxiacético (2,4-D) (0, 0.45, 2.26, 4.52 y 9.05 ųM) y kinetina (0, 2.32, 4.60, 9.30 y 13.90 ųM) con un arreglo de 5 x 5 con un ...