Ultrastructure of male gametogenesis in Chara contraria var. nitelloides (Charales, Charophyta) revisited: a model for a better characterization of the process in Charales

Abstract

Spermatogenesis in Chara contraria var. nitelloides was studied in depth. The following features were analysed: the development of cytosol, nucleus, plastids, vacuoles and dictyosomes, the coiling of the cell body, and the alignment of the organelles with the multimicrotubular roots. All of them were correlated with the dynamics of the absolute configuration of the flagellar apparatus, i.e. basal bodies and flagella. This integrating study in C. contraria var. nitelloides gives a complete portrayal of the process of spermatogenesis for the first time in the order Charales by recognizing the synchronies between the overall stages of spermatogenesis and all the developmental stages of the flagellar apparatus.