Passage cells are thin walled cells found in (a) phloem elements that serve as entry points for substance for transport to other plant parts (b) testa of seeds to enable emergence of growing embryonic axis during seed germination (c) central region of style through which the pollen tube grows towards the ovary (d) endodermis of roots facilitating rapid transport of water from cortex to pericycle.
Option D 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.
