This research work evaluated the morphology of nucellar embryos of 'Valencia' sweet orange (Citrus sinensis (L.) Osbeck), in an effort to provide this information as a reference in somatic embryo induction experiments, for in vitro breeding of this cultivar. Embryos were collected from mature fruits (13 months after blooming), and were fixed, dehydrated and prepared for serial histological cuts. Among the embryos, only one presented similar morphology to a zygotic embryo, whereas the others showed different shapes and angles in the cotyledons. Not well formed embryos were also observed, mainly due to the lack of the differentiation of the shoot apex and/or root apex, undevelopment of one of the cotyledons, or sometimes due to the collapsed embryo. The results may contribute to a better understanding of different embryo morphologies of somatic embryos and their capacity to convert in plants.
Citrus; anatomy; nucellar embryos
