Theperiplastis one of three types of cell-covering of three classes ofalgae.Thecryptomonadshave the periplast covering. TheDinophyceaehave a type called theamphiesma,and theEuglenacovering is thepellicle.
Structure
editThe periplast is a proteinaceous covering. It can be subdivided into an inner periplast and an outer periplast. Both of these components are variable in their composition.[1]
The inner periplast may be formed as a single sheet as in theChilomonas paramecium,[2]or as multiple plates of varying shape. The outer periplast surrounds the plasma membrane. The inner periplast below the plasma membrane may sometimes as inKomma caudatahave a hexagonal arrangement of superficial periplast plates, and these are made up of sub-units.[1]
The superficial plates are lined up exactly with the inner plate and are surrounded by crystalline borders with the occasional rosette scale on the surface of the plates. A number of different periplast arrangements have been described in cryptomonads. On the inner periplast part there may be seen intermembrane particles that penetrate the plasma membrane into the protoplasm. These intermembrane particles are larger around the plate boundaries.[1]
The Dinophyceae has a cell covering called the amphiesma–cisternae-like vesicles in athecalform structure. Many of the dinoflagellates have thicker thecal plates giving them the name ofarmoured dinoflagellates.The covering of theEuglenidsis called thepellicle.[1]
References
edit- ^abcdBerner, Tamar (1993).Ultrastructure of microalgae(11 ed.). CRC Press. pp. 74–78.ISBN978-0849363238.
- ^Grim, J. N.; Staehelin, L. A. (1984). "The ejectisomes of the flagellateChilomonas paramecium- Visualization by freeze-fracture and isolation techniques ".Journal of Protozoology.31(2): 259–267.doi:10.1111/j.1550-7408.1984.tb02957.x.PMID6470985.