Ultrastructure of Euglena anabaena var. minor (Euglenophyceae)

Abstract

SUMMARY The freshwater green euglenoid Euglena anabaena var. minor has a pellicle with groove-ridge articulation, a chloroplast with pyrenoids doubly sheathed by two paramylon caps, and a nucleus with permanently condensed chromosomes and nucleolus. The flagellar apparatus basically resembles that of Euglena. The dorsal root (DR) originates at the dorsal basal body of the emergent flagellum, while both the intermediate root (IR) and ventral root (VR) originate at the ventral basal body of the non-emergent flagellum. The cytoplasmic pocket is associated with the ventral root/ reinforcing microtubular band. However, ultrastructural characterization of E. anabaena var. minor shows the pocket to consist of five to seven microtubules, and flagellar roots with microtubule configuration of 3–4–6 in the DR-IR-VR. The dorsal band microtubules pair at the reservoir-canal transition level. The doublet microtubules are formed into triplets and doublets at the lower canal level and then make pellicular microtubules at the upper canal level.