Because the plasma membrane is not directly exposed to the plant cell’s environment, gaps are needed in the cell wall to allow larger molecules to move. These channels are called plasmodesmata.
Plant cells do not have gap junctions like animal cells. Instead, they have plasmodesmata (derived from the Greek word desmos ‘to bind’), which are porous connections from one plant cell to another through their cell walls. A cell’s cytosol may cross into adjacent cells through these channels.
Water and other smaller molecules–sometimes even proteins and RNA–can cross membranes through the plasmodesmata, thus facilitating the exchange of necessary nutrients and molecules throughout the plant.