PLASMODESMA

plural plasmodesmata microscopic cytoplasmic canals that pass through plant-cell walls and allow direct communication of molecules between adjacent plant cells. Plasmodesmata are formed during cell division, when traces of the endoplasmic reticulum (an organelle that synthesizes constituents of the outer cell membrane) become caught in the new wall that divides the parent cell. The two progeny cells may be connected by thousands of plasmodesmata, which contain rings of membrane at each end that are thought to regulate the passage of molecules. By overcoming the cell-wall barrier, plasmodesmata unite plant cells into functioning tissues.