Presented below is a photomicrograph of a thin section of plant tissue showing plasmodesmata cell structures. This digital image was captured with the DXM 1200 ACT-1 control software in single-image acquisition mode utilizing apodized phase contrast illumination.

Plasmodesmata (singular, plasmodesma) are small tubes that connect plant cells to each other, establishing living bridges between cells. Similar to the gap junction found in animal cells, the plasmodesmata penetrate both the primary and secondary cell walls, allowing certain molecules to pass directly from one cell to another.

These tubes, or channels, are lined with plasma membrane, uniting all connected cells with essentially one continuous cell membrane. Each plasmodesma contains a smaller tube that connects the endoplasmic reticula of the connected cells. Its mechanism isn't entirely understood yet, but the plasmodesma is thought to regulate the passage of small molecules such as salts, sugars, and amino acids by constricting or dilating the openings at each end of the channel.