Page 101 - Algae Anatomy, Biochemistry, and Biotechnology

84 Algae: Anatomy, Biochemistry, and Biotechnology

FIGURE 2.57 Root system of Chlorophyceae (Chlorophyta). 2SR, two-stranded roots; 4SR, four-stranded
roots; RHP, rhizoplasts; N, nucleus; USC, upper striated connective; and LSC, lower striated connectives.

rootlets, especially in the gametes, extend posteriorly nearly parallel to one another and to the basal
body from which they arise. Two of the rootlets (the four-membered rootlets in Trentepohlia sp.)
are associated with a complex columnar structure resembling the multilayered structure of the
Charophyceae.
Biflagellate cells of Klebsormidiophyceae such as Chaetosphaeridium sp. and Coleochaete sp.
are characterized by a unilateral construction, in which the two equal flagella emerge on one side
of the cell, below the apex. A transversely striated connective links the basal bodies. The system
anchoring the flagella in the cell consists of a single lateral root of about 60 microtubules, which
extend from the basal bodies along the cell side down to the posterior. At the level of the basal
bodies this broad root enters a multilayered structure in which the microtubules are located
between two laminate plates.
In the biflagellate male gametes of the Charophyceae the basal bodies are connected to each
other by a conspicuous fibrous linkage; the root system consists of a main broad band of micro-
tubules and a small secondary root.
Theroot system and the associated structures of the biflagellate motile cells of Dasycladophyceae
is scarcely distinguishable from those of the Cladophorophyceae. The X-2-X-2 pattern is present,
with the basal bodies and microtubular rootlets showing a flattened arrangement. A striated distal
fiber connects the proximal ends of the basal bodies, from which two prominent rhizoplasts depart.
A strongly suggested reading on this topic is the review by Moenstrup (1982).