Plasmodesmata are intercellular connections that facilitate cellular communication. Plasmodesmata occupy the cytoplasm in the openings of the cell wall, including the desmotubules between the continuous cell membrane of plant cells.
Plasmodesmata are used to circulate materials across plant cells via symplastic transport. They are all incredibly tiny, being no more than 0.3 to 0.6 microns wide each; as a result, hundreds may be present and clustered together in a primary pit field.