Effect of abscisic acid, osmolarity and temperature onin vitro development of recalcitrant mango nucellar embryos

Development of cotyledonary-stage nucellar embryos of mango was arrestedin vitro by exposure to 750–1750 M ABA. The enlargement and germination of nucellar embryos was inhibited for as long as 4 weeks after subculture from ABA-containing medium. Mannitol at concentrations between 7.5 and 12.5% inhibited nucellar embryo development, presumably due to osmotic effects; however, there was no residual effect after subculture of somatic embryos onto medium without mannitol. Temperatures between 22.5 and 37.5°C stimulated embryo development, whereas lower temperatures (7.5 and 15°C) delayed germination. There was no germination 1 month after somatic embryos, pulsed for 8 weeks at 7.5°C, were transferred to 22.5°C; however, after 2 months, 86% of these somatic embryos germinated. These results indicate that it is possible to induce developmental arrest in recalcitrant mango embryos with high concentrations of ABA, mannitol or low temperature (7.5°C).Abbreviations ABA Abscisic acid - MM1 Mango maturation medium