FHL Marine Botany  :::::::::::::::::::::::::::   Taxonomy | Habitat | Morphology | Life History | Ecology | Pit Plugs

Pit Plugs




In Scagelia occidentale pit plugs are present and were enhanced for the visual to the left by making the cells hypotonic. Pit plugs are a unique structure found in red algae and are formed through an interesting process. The process begins with cytokinesis.  During this stage it has been observed that the plant fails to completely cleave the two cells and what is formed is a channel between them. Using an electron microscope it is possible to see that after the formation of this channel, the endoplasmic reticulum is packaged up in vesicles and transported to the channel to form a plug. (Ramus 1979)

The pit plug itself is made of two parts; the plug and the cap. The image to the left illustrates these features well.  What is visible are the two membranes that come together and form the two individual rings which are the caps. The material in-between the rings are the plugs and are not visible in this image. 

It has been suggested that pit plugs might allow some connection between cells, but at this point no observations have supported this hypothesis. In Scagelia little work has been done on the pit-plug and transport mechanism, but in Porphyra there has been a lot of work suggesting that the pit plug does not allow flow between cells and the cap, after complete formation, blocks transport of material. (Ueki et al. 2008)



Ramus, J. (1979) Dimorphic pit connections in the red alga Pseudogloiophloea. Journal of Cell Biology 41: 340-345

Ueki C., Nagasato C., Motomura T., and Saga N. (2008) Reexamination of the pit plugs and the characteristic membranous structures in Porphyra yezoenis, Phycologia Vol. 47: 5-11