Cytological and taxonomic studies of the Euglenales. I. Ultrastructure and envelope elemental composition inTrachelomonas

Abstract

The ultrastructural cytology, envelope microarchitecture and elemental composition are described for species from three of Pringsheim's subgeneric categories of the euglenoid flagellate, Trachelomonas. Except for differences in chloroplast number and pyrenoid morphology, cellular organization in T. bulla, T. zorensis and T. lefevrei is similar; however, based on our finding that T. lefevrei has inner and outer paramylon caps over the pyrenoid, we propose that this species be moved from its present position in the subgroup with inner pyrenoids, to the subgroup with double-sheathed pyrenoids. Envelope microarchitecture, elemental composition and colour are correlated in each of the species. Elemental analyses indicate that envelopes or regions of envelopes with high iron content have a granular substructure, whereas those rich in manganese have a needle-like microcrystalline substructure. Envelopes of T. bulla never appear dark in the light microscope (L.M.) and have a granular microarchitecture with iron a...