Embryogenesis of Atriplex halimus L. (Amaranthaceae)

Abstract Atriplex halimus L. is a highly polymorphic species that is widespread, perennial, monoecious and polygamous. We have shown an intra—and interindividual polymorphism for several floral morphological characters including styles, ovule types and radicle orientation. A careful analysis of the female flowers with two bracteoles is performed in one plant population from Tadjerouine (Tunisia). It shows that the ovules of different flowers of individual plants are either amphitropous or campylotropous. An anatomical and histological study of pollinated ovules is done in order to search for putative variation in the embryogenesis process correlated with the ovule type. We also found unique features, both a suspensor consisting in two cellular rows and the lack of a typical torpedo stage. Moreover, this study provides evidence for some abnormal development of the embryos and for polyembryony in the amphitropous ovules.