Czech Phycology 2: 39-42, 2002
The cell wall of green alga Lagerheimia aff. subsalsa [in Czech]
Empty cell wall remnants of Lagerheimia aff. subsalsa were observed in phytoplankton sample taken in Baška reservoir near the town Frýdek-Místek (Ostrava region, Northern Moravia). The samples were collected using the plankton net (40x40 mm). Only the water passing through the net was used. Subsequently, 100 ml of the sample were filtered again, using the nitro-cellulose filter with 2.5 mm pores. The amorphous components of the cell wall remnants were naturally removed and no additional cleaning procedure was applied. The chromium shadowed tem preparation was made from diluted sediment.
in cell remnants, opposite poles of the cell bear a ring of at least 4 dense, homogenous bristles, which exceed the cell size. The cross-wise arrangement of microfibrils forms the main structural component of the cell wall. We can find similar arrangement of microfibrils in Oocystis solitaria (Trebouxiophyceae), Valonia sp. (Bryopsidophyceae), and in numerous green algae classified into Chlorophyta and Streptophyta. Some red algae exhibit similar cross-wise arrangement of microfibrils. So far, the chemical composition of microfibrils has been studied in only a few cases. In those cases, crystaline cellulose was always present and therefore considered as the main constituent of the microfibrils. In trebouxiophyceae, HEPERLE et al. (2000) considered the cross-wise arrangement of microfibrils as an important character, which confirms the classification of the alga into Trebouxiophyceae. Such idea can be correct, but only as an additional character to molecular taxonomy. Unfortunately, no species of Lagerheimia has been the subject of molecular taxonomy yet. In Kentrosphaera, WATANABE & FLOYD (1986) found the CCW orientation of basal bodies. It was the reason for the classification of that alga into Trebouxiophyceae. However GRAHAM & WILCOX (2000) considered the CCW orientation of basal bodies as a plesiomorph character, (i.e. It is similar in other groups of green algae). For this reason, the basal bodies orientation is not sufficient for a correct classification into Trebouxiophyceae. According to the original description of the class (FRIEDL 1995), the metacentric mitosis and the participation of centrioles on the formation of the phycoplast are the diacritic characters of the trebouxiophycean taxa (if the centrioles are present).
Published: March 1, 2002 Show citation
