In Vitro Megagametophyte Development via Unfertilized Ovule Culture in Doritis pulcherrima

Abstract: The ovule of Doritis pulcherrima Lindl. is anatropous, tenuinucellate and bitegmic. The mature megagametophyte is composed of seven cells with eight nuclei and its formation belongs to Allium type. Its embryo sac matures about 45 d after pollination. The megasporogenesis in vitro by ovule culture can be induced on all media whether with exogenous hormones or not 3 d after inoculation, but the later megagametogenesis will stop on the medium without hormone or only with auxin or cytokinin. Mature embryo sac can form from megaspore mother cell on the modified VW medium supplemented with 0.5 mg/L BA and 0.1 mg/L NAA. Key words: Doritis pulcherrima; ovule; embryo sac; in vitro; embryology Haploids of 21 angiosperm species have been obtained from in vitro culture of unfertilized ovules and ovaries since 1976, and most of the species are using explants at stages of uninucleate to mature embryo sac (Wu, 2003). This method is not only a viable approach of inducing haploids (Mukhambetzhanov, 1997), but also opening a new way to genetic research and regulating on the development o