Question

Passage cells are thin-walled cells found in

• A. in between xylem vessels for conduction of water
• B. testa of seed to enable the emergence of growing embryonic axis during seed germination
• C. endodermis of roots to facilitate rapid transport of water from cortex to pericycle
• D. phloem elements that serve as an entry point for substances and transportation to other parts

Answer 1

The correct option is C endodermis of roots to facilitate rapid transport of water from cortex to pericycle

Passage cells are the unthickened cells in the root endodermis lying just opposite to the protoxylem. Unlike other endodermal cells, these passage cells do not have suberin deposition. This allows them to conduct water. Since all other cells of the endodermis have suberin deposition, the passage cells serve as areas of low resistance for movement of water.

Xylem vessels have perforations in their common walls for movement of water and ions between xylem vessels. Water adsorbs (surface attraction of water molecules) on testa and helps in germination seed.

Phloem elements called sieve tubes have sieve plates which facilitate the movement of food materials from one element to another.