Passage cells are thin-walled cells found in:

The innermost layer of the cortex is called endodermis. It comprises a single layer of barrel shaped cells without any intercellular spaces. Endodermis is a single layered structure which separates cortex from stele. There are both thick walled and thin-walled cells in the endodermis. The thin-walled cells are known as passage cells or transfusion cells which are opposite the protoxylem groups. These cells help in rapid transport of water from cortex to pericycle. Related Theory Apoplast includes the non-living components of a plant such as cell walls and the intracellular spaces. In contrast, in the symplast pathway, water moves by the osmosis since water moves across the cell membranes. (Ref. to Fig. 25.4)