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The phycoplast is a microtubule structure observed during cytokinesis in members of the Chlorophytina, the largest and most well known subphylum of chlorophyte green algae. Cytokinesis in green algae occurs via a diverse range of mechanisms, including cleavage furrows in some algae and cell plates in others.
Towards the right: Phragmoplast enlarges in a donut-shape towards the outside of the cell, leaving behind mature cell plate in the center. The cell plate will transform into the new cell wall once cytokinesis is complete. The phragmoplast is a plant cell specific structure that forms during late cytokinesis.
In 1835, the German botanist and physician Hugo von Mohl described plant cell division in much greater detail in his dissertation on freshwater and seawater algae for his PhD thesis in medicine and surgery: [54] "Among the most obscure phenomena of plant life is the manner in which the newly developing cells are formed.
Algae that can divide in two planes can form sheet-like thalli or bodies. Cells that can divide in a third plane potentially allow for the organism to develop a more complex body plan, and diversification of body plans into an erect thallus of some sort and a holdfast for attaching the upright portion to the substrate.
The Ulvophyceae or ulvophytes are a class of green algae, [3] distinguished mainly on the basis of ultrastructural morphology, life cycle and molecular phylogenetic data. [4] The sea lettuce, Ulva, belongs here. Other well-known members include Caulerpa, Codium, Acetabularia, Cladophora, Trentepohlia and Monostroma.
Gonium being evolutionarily related to Chlamydomonas has a life cycle that is derivative of that of Chlamydomonas. Gonium cells grow asexually as colonies of either 4, 8 or 16 colonial cells. Cell and colony growth of Gonium is uncoupled from cell division just like Chlamydomonas and each cell within the colony divides by multiple-fission.
The life cycle of Aphanizomenon flos-aquae depends on various environmental conditions such as water temperature, dissolved oxygen content, and pH.. During the winter, Aphanizomenon flos-aquae persists as akinetes deep in the layers of sediment. [7]
Most algae have dominant gametophyte generations, but in some species the gametophytes and sporophytes are morphologically similar . An independent sporophyte is the dominant form in all clubmosses , horsetails , ferns , gymnosperms, and angiosperms that have survived to the present day.