Chlorarachniophyta

The single flagellum of the ovoid zoospores of Chlorarachmon reptans possesses a root system that consists of a microtubular component appearing as a 3þ1 structure near the level of emergence of the flagellum, soon increasing to 8 þ 1, and a second root with a homogeneous substructure that occupies a distinct concavity in the nuclear envelope.



In contrast to C. reptans, cells of Bigelowiella natans are basically biflagellate. The second flagellum, however, is exceptionally short and represented only by a barren basal body inserted at approximately right angle to the emergent flagellum. In this alga the four flagellar roots are represented by microtubular structures only with no cross-banded roots. A microtubular root is present on either sides of long flagellum basal body; the largest and most conspicuous root, which attaches to the outside of the long flagellum basal body, is five-stranded and forms an “L” in the area between the nucleous and the plasma membrane. Just before terminating, this root became two-stranded. The second microtubular root associated with the long flagellum basal body emerges from the corner between the two basal bodies and is one-stranded. The third flagellar root emerges on the outside of the short basal body and it is three-stranded. The fourth microtubular root is the most unusual; it is one-stranded and it seems to emerge within the lumen of the short basal body next to the cartwheel structure (Figure 2.56).