This is a peculiar aspects of some trophonts which remain uninucleate during the growth phase (described by Chatton). This large nucleus, which stops undergoing mitosis, progressively accumulates material which can later be used during the numerous nuclear divisions occuring during the sporogenesis. Observed in Dinophyceae such as Blastodinium and Caryotoma for example. Typical dinocaryon structure is lost at this stage.