Passage cells are thin-walled cells found in:
(a) endodermis of roots facilitating rapid transport of water from cortex to pericycle
(b) phloem elements that serve as entry points for substances for transport to other plant parts
(c) testa of seeds to enable emergence of growing embryonic axis during seed germination
(d) central region of style through which the pollen tube grows towards the ovary
(a) In roots, endodermis is the innermost layer of cortex. Some of the endodermal cells present opposite to the xylem patches are thin walled and are called passage cells or transfusion cells. Passage cells help in transfer of water and dissolved salts from cortex directly into the xylem and ultimately to the pericycle.