is a microtubule
structure observed during cytokinesis
in members of the Chlorophyceae
, the largest class of green algae.
Cytokinesis in algae occurs via a diverse range of mechanisms, including cleavage furrows
in some algae and cell plates
in others. Some green algae use phragmoplasts
like higher plants to organize and guide the growing cell plate. In these algae, the microtubules of the telophase spindle give rise to the phragmoplast and are oriented perpendicular to the plane of cell division and the forming cell plate.
Another common form of cell division in green algae occurs via a phycoplast. In these algea, the spindle collapses and a new system of microtubules forms that is oriented in parallel to the plane of cell division. This phycoplast can be observed in green algae undergoing cytokinesis via cleavage furrow as well as algae utilizing a cell plate. The phycoplast may play a role in assuring that the plane of cell division will pass between the two daughter nuclei. Typically, these algae undergo "closed" mitosis
where the nuclear envelope
persists throughout mitosis.
- P.H. Raven, R.F. Evert, S.E. Eichhorn (2005): Biology of Plants, 7th Edition, W.H. Freeman and Company Publishers, New York, ISBN 0-7167-1007-2