Symplast

The symplast of a plant is the region enclosed by the cell membranes, within which water and solutes can diffuse freely.

Larger molecules, including transcription factors and plant viruses, can also be transported through with the help of actin structures.

The symplast allows direct cytoplasm-to-cytoplasm flow of water and other nutrients along concentration gradients.

Once solutes in the soil water reach the endodermal cells through apoplastic flow, they are forced into the symplastic pathway due to the presence of the Casparian strip.

Once the solutes are passively filtered[clarification needed], they eventually reach the pericycle, where they can be moved into the xylem for long-distance transport.