Microspores can be reprogrammed by stress, e.g.high and/or low temperature treatment to shift from gametophytic development towards a sporophytic pathway, a process known as androgenesis.In conventional microspore culture system the first symmetric division of microspore was a key factor in the determination of subsequent development.Then following a series of random divison multicellular proembryo structures are formed, which is distinct from normal zygotic embryogenesis.Furthermore, susupensor development is absent in those microspore-derived embryos, although a rudimentary suspensor-like structure is occasionally occurred.This limits the application of the system in the investigation of the early developmental events of embryogenesis.In this work, the exine-dehised microspore culture system, a new microspore culture system,was used to analyze the spatial distribution of the first cell division in the exine-dehisced microspore.The results suggested that the orientation of the first cell division plane was determined by the broken exine.Sometimes mechanical role of the exine is followed to assay.