Plasmodesma

Plasmodesma (plural is 'plasmodesmata') is a microscopic channel across the cell wall of a plant cell.^[2][3] It allows transport and communication between neighbouring cells. Plasmodesmata also evolved independently in some algae.

Plasmodesma allow molecules to travel between plant cells through the symplastic pathway

The structure of a primary plasmodesma. CW=Cell wall CA=Callose PM=Plasma membrane ER=Endoplasmic reticulum DM=Desmotubule Red circles=Actin Purple circles and spokes=Other unidentified proteins.^[1]

Unlike animal cells, every plant cell is surrounded by a polysaccharide cell wall. Neighbouring plant cells are therefore separated by a pair of cell walls. Although cell walls are permeable to small soluble molecules, plasmodesmata allow direct, regulated, intercellular transport of substances between cells.^[4]

Similar structures connect animal cells.^[5][6] Stromules form between plastids in plant cells.^[7]