Effect of morphological heterogeneity of somatic embryos of Melia azedarach on conversion into plants

Embryogenic cultures were initiated from immature Melia azedarach (Meliaceae) zigotic embryos. Explains were induced on Murashige and Skoog (1962) medium with 4.54 mu M thidiazuron or 0.45 mu M dichlorophenoxyacetic acid. After 6 weeks of culture on induction medium, somatic embryos were categorized in four morphological classes based on the presence of single or fused embryos and if they remained united or not to the original explain; that were evaluated histologically. The somatic embryos of every category were transferred, in groups or individually, on a 1/4 MS medium. Bipolar embryos, the more typically normal ones, had well defined shoot and root apical meristems and produced single plants; subcultured individually their conversion was 28%, and subcultured in groups the conversion declined to 6.8%. Fused embryos subcultured ill groups had only a 2.1% conversion and produced plants with fused stems. None conversion rate in the others classes was associated to poorly developed shoot and root meristematic areas or with their absence. The converted plants were acclimatized and transferred, in a mist, to soil, with an independent of the class 95% survival rate.