Trebouxiophyceae

The Trebouxiophyceae are a class of algae that belongs to the Chlorophyta, one of two major groups of green algae.

Features

The representatives are flagellated unicellular or unbegeißelte, as well as branched and unbranched filamentous forms.

The floating cells possess one or two pairs of flagella without mastigonema. The basal bodies have four microtubule roots in cruciform arrangement, including a multi-layered structure and a smaller root. The basal bodies have a distinct Rhizoplasten. The whole Flagellenapparat arranged counterclockwise. Mitosis is closed with a metacentric mitotic spindle, also semi-closed mitosis occurs. Cell division takes place by means Phycoplast.

The asexual reproduction is via spores or zoospores car. Sexual reproduction was observed. The food is made by autotrophy (photosynthesis ) or Osmotrophie. Prototheca, a coccal shape, secondarily lost the ability to photosynthesize.

Occurrence

The members of the group live free or form lichens. They occur both in freshwater and in seawater, some representatives also live terrestrial.

System

This class is likely to be monophyletic, but this is not yet enough coverage. The individual orders are likely to be monophyletic:

• Trebouxiales: these are primarily lichen -forming shapes that form zoospores. Representatives are Trebouxia, Myrmecia.
• Microthamniales: zoospore -forming unicellular to branched filaments. Microthamnion, Fusochloris
• Prasiolales: form zoospores; Unicellular organisms to sheet-like thalli. Widely used in freshwater, marine and terrestrial. Some species live in cold deserts as Pabia signiensis in Antarctica. Example: Prasiola, Stichococcus.
• Chlorellales: Car Make spores. Family Chlorellaceae: inter alia, Chlorella
• Family Oocystaceae