Passage cells are thin walled cells found in

(1) central region of style through which the pollen tube grows towards the
ovary
(2) phloem elements that serve as entry points for substance for transport ot
other plant parts
(3) endodermis of roots facilitating rapid transport of water from cortex to
pericycle.
(4) testa of seeds to enable emergence of growing embryonic axis during seed
germination